part ii

. completing the work in May 1823. Constable, thinking it not wise to reprint so large a book year after year without correction, in 1820 selected Mr Charles Maclaren (1782-1866), as editor. "His attention was chiefly directed to the historical and geographical articles. He was to keep the press going, and have the whole completed in three years." He wrote "America," "Greece," "Troy," &c. Many of the large articles as "Agriculture," "Chemistry," "Conchology," were new or nearly so; and references were given to the supplement. A new edition in 25 vols. was contemplated, not to be announced till a certain time after the supplement was finished; but Constable's house stopped payment on the 19th of January 1826, and his copyrights were sold by auction. Those of the _Encyclopaedia_ were bought by contract, on the 16th of July 1828, for L6150, by Thomas Allan, proprietor of the _Caledonian Mercury_, Adam Black, Abram Thomson, bookbinder, and Alexander Wight, banker, who, with the trustee of Constable's estate, had previously begun the seventh edition. Not many years later Mr Black purchased all the shares and became sole proprietor.

The seventh edition, 21 vols. 4to (with an index of 187 pages, compiled by Robert Cox), containing 17,101 pages and 506 plates, edited by Macvey Napier, assisted by James Browne, LL.D., was begun in 1827, and published from March 1830 to January 1842. It was reset throughout and stereotyped. Mathematical diagrams were printed in the text from woodcuts. The first half of the preface was nearly that of the supplement. The list of signatures, containing 167 names, consists of four alphabets with additions, and differs altogether from that in the supplement: many names are omitted, the order is changed and 103 are added. A list follows of over 300 articles, without signatures, by 87 writers. The dissertations--1st, Stewart's, 289 pages; 2nd, "Ethics" (136 pages), by Sir James Mackintosh, whose death prevented the addition of "Political Philosophy"; 3rd, Playfair's, 139 pages; 4th, its continuation by Sir John Leslie, 100 pages--and their index of 30 pages, fill vol. i. As they did not include Greek philosophy, "Aristotle," "Plato" and "Socrates" were supplied by Dr Hampden, afterwards bishop of Hereford. Among the numerous contributors of eminence, mention may be made of Sir David Brewster, Prof. Phillips, Prof. Spalding, John Hill Burton, Thomas De Quincey, Patrick Fraser Tytler, Capt. Basil Hall, Sir Thomas Dick Lauder, Antonio Panizzi, John Scott Russell and Robert Stephenson. Zoology was divided into 11 chief articles, "Mammalia," "Ornithology," "Reptilia," "Ichthyology," "Mollusca," "Crustacea," "Arachnides," "Entomology," "Helminthology," "Zoophytes," and "Animalcule"--all by James Wilson.

The eighth edition, 1853-1860, 4to, 21 vols. (and index of 239 pages, 1861), containing 17,957 pages and 402 plates, with many woodcuts, was edited by Dr Thomas Stewart Traill, professor of medical jurisprudence in Edinburgh University. The dissertations were reprinted, with one on the "Rise, Progress and Corruptions of Christianity" (97 pages), by Archbishop Whately, and a continuation of Leslie's to 1850, by Professor James David Forbes, 198 pages, the work of nearly three years, called by himself his "magnum opus" (Life, pp. 361, 366). Lord Macaulay, Charles Kingsley, Isaac Taylor, Hepworth Dixon, Robert Chambers, Rev. Charles Merivale, Rev. F.W. Farrar, Sir John Richardson, Dr Scoresby, Dr Hooker, Henry Austin Layard, Edw. B. Eastwick, John Crawfurd, Augustus Petermann, Baron Bunsen, Sir John Herschel, Dr Lankester, Professors Owen, Rankine, William Thomson, Aytoun, Blackie, Daniel Wilson and Jukes, were some of the many eminent new contributors found among the 344 authors, of whom an alphabetical list is given, with a key to the signatures. In the preface a list of 279 articles by 189 writers, classed under 15 heads, is given. This edition was not wholly reset like the seventh, but many long articles were retained almost or entirely intact.

The publication of the ninth edition (A. & C. Black) was commenced in January 1875, under the editorship of Thomas Spencer Baynes until 1880, and subsequently of W. Robertson Smith, and completed in 1889, 24 vols., with index. This great edition retained a certain amount of the valuable material in the eighth, but was substantially a new work; and it was universally acknowledged to stand in the forefront of the scholarship of its time. Its contributors included the most distinguished men of letters and of science. In 1898 a reprint, sold at about half the original price, and on the plan of payment by instalments, was issued by _The Times_ of London; and in 1902, under the joint editorship of Sir Donald Mackenzie Wallace, President Arthur T. Hadley of Yale University, and Hugh Chisholm, eleven supplementary volumes were published, forming, with the 24 vols. of the ninth edition, a tenth edition of 35 volumes. These included a volume of maps, and an elaborate index (vol. 35) to the whole edition, comprising some 600,000 entries. In May 1903 a start was made with the preparation of the 11th edition, under the general editorship of Hugh Chisholm, with W. Alison Phillips as chief assistant-editor, and a staff of editorial assistants, the whole work of organization being conducted up to December 1909 from _The Times_ office. Arrangements were then made by which the copyright and control of the _Encyclopaedia Britannica_ passed to Cambridge University, for the publication at the University Press in 1910-1911 of the 29 volumes (one being Index) of the 11th edition, a distinctive feature of this issue being the appearance of the whole series of volumes practically at the same time.

A new and enlarged edition of the _Encyclopedie_ arranged as a system of separate dictionaries, and entitled _Encyclopedie methodique ou par ordre de matieres_, was undertaken by Charles Joseph Panckoucke, a publisher of Paris (born at Lille on the 26th of November 1736, died on the 19th of December 1798). His privilege was dated the 20th of June 1780. The articles belonging to different subjects would readily form distinct dictionaries, although, having been constructed for an alphabetical plan, they seemed unsuited for any system wholly methodical. Two copies of the book and its supplement were cut up into articles, which were sorted into subjects. The division adopted was: 1, mathematics; 2 physics; 3, medicine; 4, anatomy and physiology; 5, surgery; 6, chemistry, metallurgy and pharmacy; 7, agriculture; 8, natural history of animals, in six parts; 9, botany; 10, minerals; 11, physical geography; 12, ancient and modern geography; 13, antiquities; 14, history; 15, theology; 16, philosophy; 17, metaphysics, logic and morality; 18, grammar and literature; 19, law; 20, finance; 21, political economy; 22, commerce; 23, marine; 24, art militaire; 25, beaux arts; 26, arts et metiers--all forming distinct dictionaries entrusted to different editors. The first object of each editor was to exclude all articles belonging to other subjects, and to take care that those of a doubtful nature should not be omitted by all. In some words (such as air, which belonged equally to chemistry, physics and medicine) the methodical arrangement has the unexpected effect of breaking up the single article into several widely separated. Each dictionary was to have an introduction and a classified table of the principal articles. History and its minor parts, as inscriptions, fables, medals, were to be included. Theology, which was neither complete, exact nor orthodox, was to be by the abbe Bergier, confessor to Monsieur. The whole work was to be completed and connected together by a Vocabulaire Universel, 1 vol. 4to, with references to all the places where each word occurred, and a very exact history of the _Encyclopedie_ and its editions by Panckoucke. The prospectus, issued early in 1782, proposed three editions--84 vols. 8vo, 43 vols. 4to with 3 columns to a page, and 53 vols. 4to of about 100 sheets with 2 columns to a page, each edition having 7 vols. 4to of 250 to 300 plates each. The subscription was to be 672 livres from the 15th of March to July 1782, then 751, and 888 after April 1783. It was to be issued in livraisons of 2 vols. each, the first (jurisprudence, vol. i., literature, vol. i.) to appear in July 1782, and the whole to be finished in 1787. The number of subscribers, 4072, was so great that the subscription list of 672 livres was closed on the 30th of April. Twenty-five printing offices were employed, and in November 1782 the 1st livraison (jurisprudence, vol. i., and half vol. each of arts et metiers and histoire naturelle) was issued. A Spanish prospectus was sent out, and obtained 330 Spanish subscribers, with the inquisitor-general at their head. The complaints of the subscribers and his own heavy advances, over 150,000 livres, induced Panckoucke, in November 1788, to appeal to the authors to finish the work. Those _en retard_ made new contracts, giving their word of honour to put their parts to press in 1788, and to continue them without interruption, so that Panckoucke hoped to finish the whole, including the vocabulary (4 or 5 vols.), in 1792. Whole sciences, as architecture, engineering, hunting, police, games, &c., had been overlooked in the prospectus; a new division was made in 44 parts, to contain 51 dictionaries and about 124 vols. Permission was obtained on the 27th of February 1789, to receive subscriptions for the separate dictionaries. Two thousand subscribers were lost by the Revolution. The 50th livraison appeared on the 23rd of July 1792, when all the dictionaries eventually published had been begun except seven--jeux familiers and mathematiques, physics, art oratoire, physical geography, chasses and peches; and 18 were finished,--mathematics, games, surgery, ancient and modern geography, history, theology, logic, grammar, jurisprudence, finance, political economy, commerce, marine, arts militaires, arts academiques, arts et metiers, encyclopediana. Supplements were added to military art in 1797, and to history in 1807, but not to any of the other 16, though required for most long before 1832. The publication was continued by Henri Agasse, Panckoucke's son-in-law, from 1794 to 1813, and then by Mme Agasse, his widow, to 1832, when it was completed in 102 livraisons or 337 parts, forming 166-1/2 vols. of text, and 51 parts containing 6439 plates. The letterpress issued with the plates amounts to 5458 pages, making with the text 124,210 pages. To save expense the plates belonging to architecture were not published. Pharmacy (separated from chemistry), minerals, education, ponts et chaussees had been announced but were not published, neither was the Vocabulaire Universel, the key and index to the whole work, so that it is difficult to carry out any research or to find all the articles on any subject. The original parts have been so often subdivided, and have been so added to by other dictionaries, supplements and appendices, that, without going into great detail, an exact account cannot be given of the work, which contains 88 alphabets, with 83 indexes, and 166 introductions, discourses, prefaces, &c. Many dictionaries have a classed index of articles; that of economie politique is very excellent, giving the contents of each article, so that any passage can be found easily. The largest dictionaries are medicine, 13 vols., 10,330 pages; zoology, 7 dictionaries, 13,645 pages, 1206 plates; botany, 12,002 pages, 1000 plates (34 only of cryptogamic plants); geography, 3 dictionaries and 2 atlases, 9090 pages, 193 maps and plates; jurisprudence (with police and municipalities), 10 vols., 7607 pages. Anatomy, 4 vols., 2866 pages, is not a dictionary but a series of systematic treatises. Assemblee Nationale was to be in three parts,--(1) the history of the Revolution, (2) debates, and (3) laws and decrees. Only vol. ii., debates, appeared, 1792, 804 pages, Absens to Aurillac. Ten volumes of a Spanish translation with a vol. of plates were published at Madrid to 1806--viz. historia natural, i. ii.; grammatica, i.; arte militar, i., ii.; geografia, i.-iii.; fabricas, i., ii., plates, vol. i. A French edition was printed at Padua, with the plates, says Peignot, very carefully engraved. Probably no more unmanageable body of dictionaries has ever been published except Migne's _Encyclopedie theologique_, Paris, 1844-1875, 4to, 168 vols., 101 dictionaries, 119,059 pages.

No work of reference has been more useful and successful, or more frequently copied, imitated and translated, than that known as the _Conversations Lexikon_ of Brockhaus. It was begun as _Conversations Lexikon mit vorzuglicher Rucksicht auf die gegenwartigen Zeiten_, Leipzig, 1796 to 1808, 8vo, 6 vols., 2762 pages, by Dr Gotthelf Renatus Lobel (born on the 1st of April 1767 at Thalwitz near Wurzen in Saxony, died on the 14th of February 1799), who intended to supersede Hubner, and included geography, history, and in part biography, besides mythology, philosophy, natural history, &c. Vols. i.-iv. (A to R) appeared 1796 to 1800, vol. v. in 1806. Friedrich Arnold Brockhaus (q.v.) bought the work with its copyright on the 25th of October 1808, for 1800 thalers from the printer, who seems to have got it in payment of his bill. The editor, Christian Wilhelm Franke, by contract dated the 16th of November, was to finish vol. vi. by the 5th of December, and the already projected supplement, 2 vols., by Michaelmas 1809, for 8 thalers a printed sheet. No penalty was specified, but, says his grandson, Brockhaus was to learn that such contracts, whether under penalty or not, are not kept, for the supplement was finished only in 1811. Brockhaus issued a new impression as _Conversations Lexikon oder kurzgefasstes Handworterbuch_, &c, 1809-1811, and on removing to Altenburg in 1811 began himself to edit the 2nd edition (1812-1819, 10 vols.), and, when vol. iv. was published, the 3rd (1814-1819). He carried on both editions together until 1817, when he removed to Leipzig, and began the 4th edition as _Allgemeine deutsche Realencyclopadie fur die gebildeten Stande. Conversations Lexikon_. This title was, in the 14th edition, changed to that of _Brockhaus' Konversations Lexicon_. The 5th edition was at once begun, and was finished in eighteen months. Dr Ludwig Hain assisted in editing the 4th and 5th editions until he left Leipzig in April 1820, when Professor F.C. Hasse took his place. The 12,000 copies of the 5th edition being exhausted while vol. x. was at press, a 2nd unaltered impression of 10,000 was required in 1820 and a 3rd of 10,000 in 1822. The 6th edition, 10 vols., was begun in September 1822. Brockhaus died in 1823, and his two eldest sons, Friedrich and Heinrich, who carried on the business for the heirs and became sole possessors in 1829, finished the edition with Hasse's assistance in September 1823. The 7th edition (1827-1829, 12 vols., 10,489 pages, 13,000 copies, 2nd impression 14,000) was edited by Hasse. The 8th edition (1833-1836, 12 vols., 10,689 pages, 31,000 copies to 1842), begun in the autumn of 1832, ended May 1837, was edited by Dr Karl August Espe (born February 1804, died in the Irrenanstalt at Stotteritz near Leipzig on the 24th of November 1850) with the aid of many learned and distinguished writers. A general index, Universal Register, 242 pages, was added in 1839. The 9th edition (1843-1847, 15 vols., 11,470 pages, over 30,000 copies) was edited by Dr Espe. The 10th edition (1851-1855, 12,564 pages) was also in 15 vols., for convenience in reference, and was edited by Dr August Kurtzel aided by Oskar Pilz. Friedrich Brockhaus had retired in 1849; Dr Heinrich Edward, the elder son of Heinrich, made partner in 1854, assisted in this edition, and Heinrich Rudolf, the younger son, partner since 1863, in the 11th (1864-1868, 15 vols. of 60 sheets, 13,366 pages).

Kurtzel died on the 24th of April 1871, and Pilz was sole editor until March 1872, when Dr Gustav Stockmann joined, who was alone from April until joined by Dr Karl Wippermann in October. Besides the Universal Register of 136 pages and about 50,000 articles, each volume has an index. The supplement, 2 vols, 1764 pages, was begun in February 1871, and finished in April 1873. The 12th edition, begun in 1875, was completed in 1879 in 15 vols., the 13th edition (1882-1887), in 16 vols., and the 14th (1901-1903) in 16 vols. with a supplementary volume in 1904. The _Conversations Lexicon_ is intended, not for scientific use, but to promote general mental improvement by giving the results of research and discovery in a simple and popular form without extended details. The articles, often too brief, are very excellent and trustworthy, especially on German subjects, give references to the best books, and include biographies of living men.

One of the best German encyclopaedias is that of Meyer, _Neues Konversations-Lexicon_. The first edition, in 37 vols., was published in 1839-1852. The later editions, following closely the arrangement of Brockhaus, are the 4th (1885-1890, 17 vols.), the 5th (1894-1898, 18 vols.), and the 6th (begun in 1902).

The most copious German encyclopaedia is Ersch and Gruber's _Allgemeine Encyklopadie der Wissenschaften und Kunste_, Leipzig. It was designed and begun in 1813 by Professor Johann Samuel Ersch (born at Gross Glogau on the 23rd of June 1766, chief librarian at Halle, died on the 16th of January 1828) to satisfy the wants of Germans, only in part supplied by foreign works. It was stopped by the war until 1816, when Professor Hufeland (born at Danzig on the 19th of October 1760) joined, but he died on the 25th of November 1817 while the specimen part was at press. The editors of the different sections at various times have been some of the best-known men of learning in Germany, including J.G. Gruber, M.H.E. Meier, Hermann Brockhaus, W. Muller and A.G. Hoffmann of Jena.

The work is divided into three sections (1) A-G, of which 99 vols. had appeared by 1905, (2) H-N, 43 vols., (3) O-Z, 25 vols. All articles bear the authors' names, and those not ready in time were placed at the end of their letter. The longest in the work is Griechenland, vols. 80-87, 3668 pages, with a table of contents. It began to appear after vol. 73 (Gotze to Gondouin), and hence does not come in its proper place, which is in vol. 91. Gross Britannien contains 700 pages, and Indien by Benfey 356.

The _Encyclopaedia Metropolitana_ (London, 1845, 4to, 28 vols., issued in 59 parts in 1817-1845, 22,426 pages, 565 plates) professed to give sciences and systematic arts entire and in their natural sequence, as shown in the introductory treatise on method by S.T. Coleridge. "The plan was the proposal of the poet Coleridge, and it had at least enough of a poetical character to be eminently unpractical" (_Quarterly Review_, cxiii., 379). However defective the plan, the excellence of many of the treatises by Archbishop Whately, Sir John Herschel, Professors Barlow, Peacock, de Morgan, &c., is undoubted. It is in four divisions, the last only being alphabetical:--I. _Pure Sciences_, 2 vols., 1813 pages, 16 plates, 28 treatises, includes grammar, law and theology; II. _Mixed and Applied Sciences_, 8 vols., 5391 pages, 437 plates, 42 treatises, including fine arts, useful arts, natural history and its "application," the medical sciences; III. _History and Biography_, 5 vols., 4458 pages, 7 maps, containing biography (135 essays) chronologically arranged (to Thomas Aquinas in vol. 3), and interspersed with (210) chapters on history (to 1815), as the most philosophical, interesting and natural form (but modern lives were so many that the plan broke down, and a division of biography, to be in 2 vols., was announced but not published); IV. _Miscellaneous_, 12 vols., 10,338 pages, 105 plates, including geography, a dictionary of English (the first form of Richardson's) and descriptive natural history. The index, 364 pages, contains about 9000 articles. A re-issue in 38 vols. 4to, was announced in 1849. Of a second edition 42 vols. 8vo, 14,744 pages, belonging to divisions i. to iii., were published in 1849-1858.

The very excellent and useful _English Cyclopaedia_ (London, 1854-1862, 4to, 23 vols., 12,117 pages; supplements, 1869-1873, 4 vols., 2858 pages), conducted by Charles Knight, based on the _Penny Cyclopaedia_ (London, 1833-1846, 4to, 29 vols., 15,625 pages), of which he had the copyright, is in four divisions all alphabetical, and evidently very unequal as classes:--1, geography; 2, natural history; 3, biography (with 703 lives of living persons); 4, arts and sciences. The synoptical index, 168 pages, has four columns on a page, one for each division, so that the order is alphabetical and yet the words are classed.

_Chambers's Encyclopaedia_ (Edinburgh, W. & R. Chambers), 1860-1868, 8vo, 10 vols., 8283 pages, edited in part by the publishers, but under the charge of Dr Andrew Findlater as "acting editor" throughout, was founded on the 10th edition of _Brockhaus_. A revised edition appeared in 1874, 8320 pages. In the list of 126 contributors were J.H. Burton, Emmanuel Deutsch, Professor Goldstucker, &c. The index of matters not having special articles contained about 1500 headings. The articles were generally excellent, more especially on Jewish literature, folk-lore and practical science; but, as in _Brockhaus_, the scope of the work did not allow extended treatment. A further revision took place, and in 1888-1892 an entirely new edition was published, in 10 vols., still further new editions being issued in 1895 and in 1901.

An excellent brief compilation, the _Harmsworth Encyclopaedia_ (1905), was published in 40 fortnightly parts (sevenpence each) in England, and as _Nelson's Encyclopaedia_ (revised) in 12 vols. (1906) in America. It was originally prepared for Messrs Nelson of Edinburgh and for the Carmelite Press, London.

In the United States various encyclopaedias have been published, but without rivalling there the _Encyclopaedia Britannica_, the 9th edition of which was extensively pirated. Several American Supplements were also issued.

The _New American Cyclopaedia_, New York (Appleton & Co.), 1858-1863, 16 vols., 12,752 pages, was the work of the editors, George Ripley and Charles Anderson Dana, and 364 contributors, chiefly American. A supplementary work, the _American Annual Cyclopaedia_, a yearly 8vo vol. of about 800 pages and 250 articles, was started in 1861, but ceased in 1902. In a new edition, the _American Cyclopaedia_, 1873-1876, 8vo, 16 vols., 13,484 pages, by the same editors, 4 associate editors, 31 revisers and a librarian, each article passed through the hands of 6 or 8 revisers.

Other American encyclopaedias are Alvin J. Johnson's _New Universal Cyclopaedia_, 1875-1877, in 4 vols., a new edition of which (excellently planned) was published in 8 vols., 1893-1895, under the name of _Johnson's Universal Cyclopaedia_; the _Encyclopaedia Americana_, edited by Francis Lieber, which appeared in 1839-1847 in 14 vols.; a new work under the same title, published in 1903-1904 in 16 vols.; the _International Cyclopaedia_, first published in 1884 (revised in 1891, 1894 and 1898), and superseded in 1902 (revised, 1906) by the _New International Encyclopaedia_ in 17 vols.

In Europe a great impetus was given to the compilation of encyclopaedias by the appearance of Brockhaus' _Conversations-Lexicon_ (see above), which, as a begetter of these works, must rank, in the 19th century, with the _Cyclopaedia_ of Ephraim Chambers in the 18th. The following, although in no sense an exhaustive list, may be here mentioned. In France, _Le Grand Dictionnaire universel du XIX^e siecle_, of Pierre Larousse (15 vols., 1866-1876), with supplementary volumes in 1877, 1887 and 1890; the _Nouveau Larousse illustre, dictionnaire universel encyclopedique_ (7 vols., 1901-1904), (this is in no way a re-issue or an abridgment of _Le Grand Dictionnaire_ of Pierre Larousse); _La Grande Encyclopedie, inventaire raisonne des sciences, des lettres, et des arts_, in 31 vols. (1886-1903). In Italy, the _Nuova Enciclopedia Italiana_ (14 vols., 1841-1851, and in 25 vols., 1875-1888). In Spain, the _Diccionario enciclopedico Hispano-Americano de litteratura, ciencias y artes_, published at Barcelona (25 vols., 1877-1899). The Russian encyclopaedia, _Russkiy Entsiklopedicheskiy Slovar_ (41 vols., 1905, 2 supplementary vols., 1908) was begun in 1890 as a Russian version of Brockhaus' _Conversations-Lexicon_, but has become a monumental encyclopaedia, to which all the best Russian men of science and letters have contributed. Elaborate encyclopaedias have also appeared in the Polish, Hungarian, Bohemian and Rumanian languages. Of Scandinavian encyclopaedias there have been re-issues of the _Nordesk Conversations-Lexicon_, first published in 1858-1863, and of the _Svenskt Conversations-Lexicon_, first published in 1845-1851.

ENDECOTT, JOHN (c. 1588-1665), English colonial governor in America, was born probably at Dorchester, Dorsetshire, England, about 1588. Little is known of him before 1628, when he was one of the six "joint adventurers" who purchased from the Plymouth Company a strip of land about 60 m. wide along the Massachusetts coast and extending westward to the Pacific Ocean. By his associates Endecott was entrusted with the responsibility of leading the first colonists to the region, and with some sixty persons proceeded to Naumkeag (later Salem) where Roger Conant, a seceder from the colony at Plymouth, had begun a settlement two years earlier. Endecott experienced some trouble with the previous settlers and with Thomas Morton's settlement at "Merry Mount" (Mount Wollaston, now Quincy), where, in accordance with his strict Puritanical tenets, he cut down the maypole and dispersed the merrymakers. He was the local governor of the Massachusetts Bay Colony from the 30th of April 1629 to the 12th of June 1630, when John Winthrop, who had succeeded Matthew Cradock as governor of the company on the 20th of October 1629, brought the charter to Salem and became governor of the colony as well as of the company. In the years immediately following he continued to take a prominent part in the affairs of the colony, serving as an assistant and as a military commissioner, and commanding, although with little success, an expedition against the Pequots in 1636. At Salem he was a member of the congregation of Roger Williams, whom he resolutely defended in his trouble with the New England clerical hierarchy, and excited by Williams's teachings, cut the cross of St George from the English flag in token of his hatred of all symbols of Romanism. He was deputy-governor in 1641-1644, and governor in 1644-1645, and served also as sergeant-major-general (commander-in-chief) of the militia and as one of the commissioners of the United Colonies of New England, of which in 1658 he was president. On the death of John Winthrop in 1649 he became governor, and by annual re-elections served continuously until his death, with the exception of two years (1650-1651 and 1654-1655), when he was deputy-governor. Under his authority the colony of Massachusetts Bay made rapid progress, and except in the matter of religious intolerance--he showed great bigotry and harshness, particularly towards the Quakers--his rule was just and praiseworthy. Of him Edward Eggleston says: "A strange mixture of rashness, pious zeal, genial manners, hot temper, and harsh bigotry, his extravagances supply the condiment of humour to a very serious history--it is perhaps the principal debt posterity owes him." He died on the 15th of March 1665.

See C.M. Endicott, _Memoirs of John Endecott_ (Salem, 1847), and a "Memoir of John Endecott" in _Antiquarian Papers_ of the American Antiquarian Society (Worcester, Mass., 1879).

A lineal descendant, WILLIAM CROWNINSHIELD ENDICOTT (1826-1900), graduated at Harvard in 1847, was a justice of the Massachusetts supreme court in 1873-1882, and was secretary of war in President Cleveland's cabinet from 1885 to 1889. His daughter, Mary Crowninshield Endicott, was married to the English statesman Mr Joseph Chamberlain in 1888.

ENDIVE, _Cichorium Endivia_, an annual esculent plant of the natural order Compositae, commonly reputed to have been introduced into Europe from the East Indies, but, according to some authorities, more probably indigenous to Egypt. It has been cultivated in England for more than three hundred years, and is mentioned by John Gerarde in his _Herbal_ (1597). There are numerous varieties of the endive, forming two groups, namely, the curled or narrow-leaved (var. _crispa_), and the Batavian or broad-leaved (var. _latifolia_), the leaves of which are not curled. The former varieties are those most used for salads, the latter being grown chiefly for culinary purposes. The plant requires a light, rich and dry soil, in an unshaded situation. In the climate of England sowing for the main crop should begin about the second or third week in June; but for plants required to be used young it may be as early as the latter half of April, and for winter crops up to the middle of August. The seed should be finely spread in drills 4 in. asunder, and then lightly covered. After reaching an inch in height the young plants are thinned; and when about a month old they may be placed out at distances of 12 or 15 in., in drills 3 in. in depth, care being taken in removing them from the seed-bed to disturb their roots as little as possible. The Batavian require more room than the curled-leaved varieties. Transplantation, where early crops are required, has been found inadvisable. Rapidity of growth is promoted by the application of liquid manures. The bleaching of endive, in order to prevent the development of the natural bitter taste of the leaves, and to improve their appearance, is begun about three months after the sowing, and is best effected either by tying the outer leaves around the inner, or, as in damp seasons, by the use of the bleaching-pot. The bleaching may be completed in ten days or so in summer, but in winter it takes three or four weeks. For late crops, protection from frost is requisite; and to secure fine winter endive, it has been recommended to take up the full-grown plants in November, and to place them under shelter, in a soil of moderately dry sand or of half-decayed peat earth. Where forcing-houses are employed, endive may be sown in January, so as to procure by the end of the following month plants ready for use.

ENDOEUS, an early sculptor, who worked at Athens in the middle of the 6th century B.C. We are told that he made an image of Athena dedicated by Callias the contemporary of Pisistratus at Athens about 564 B.C. An inscription bearing his name has been found at Athens, written in Ionian dialect. The tradition which made him a pupil of Daedalus is apparently misleading, since Daedalus had no connexion with Ionic art.

ENDOGAMY (Gr. [Greek: endon], within, and [Greek: gamos], marriage), marriage within the tribe or community, the term adopted to express the custom compelling those of a tribe to marry among themselves. Endogamy was probably characteristic of the very early stages of social organization (see FAMILY), and is to-day found only among races low in the scale of civilization. As a custom it is believed to have been preceded in most lands by the far more general rule of Exogamy (q.v.). Lord Avebury (_Origin of Civilisation_, p. 154) points out that "there is not the opposition between exogamy and endogamy which Mr McLennan supposed." Some races which are endogamous as regards the tribe are exogamous as regards the gens. Thus the Abors, Kochs, Hos and other peoples of India, are forbidden to marry out of the tribe; but the tribe itself is divided into "keelis" or clans, and no man is allowed to take as wife a girl of his own "keeli". Endogamy must have in most cases arisen from racial pride, and a contempt, either well or ill founded, for the surrounding peoples.

Among the Ahtena of Alaska, though the tribes are extremely militant and constantly at war, the captured women are never made wives, but are used as slaves. Endogamy also prevails among tribes of Central America. With the Yerkalas of southern India a custom prevails by which the first two daughters of a family may be claimed by the maternal uncle as wives for his sons. The value of a wife is fixed at twenty pagodas (a 16th-century Indian coin equivalent to about five shillings), and should the uncle forgo his claim he is entitled to share in the price paid for his nieces. Among some of the Karen tribes marriages between near relatives are usual. The Douignaks, a branch of the Chukmas, seem to have practised endogamy; and they "abandoned the parent stem during the chiefship of Janubrix Khan about 1782. The reason of this split was a disagreement on the subject of marriages. The chief passed an order that the Douignaks should intermarry with the tribe in general. This was contrary to an ancient custom and caused discontent and eventually a break in the tribe" (Lewin's _Hill Tracts of Chittagong_, p. 65). This is interesting as being one of the few cases in which evidence of a change in this respect is available. The Kalangs of Java are endogamous, and every man must first prove his common descent before he can enter a family. The Manchu Tatars prohibit those who have the same family names from marrying. Among the Bedouins "a man has an exclusive right to the hand of his cousin." Hottentots seldom marry out of their own kraal, and David Livingstone quotes other examples. Endogamy seems to have existed in the Sandwich Islands and in New Zealand. A community of Javans near Surabaya, on the Teugger Hills, numbering about 1200 persons, distributed in about forty villages, and still following the ancient Hindu religion, is endogamous. Good examples of what biologists call "in-and-in breeding" are to be found in various fishing villages in Great Britain, such as Itchinferry, near Southampton, Portland Island, Bentham in Yorkshire, Mousehole and Newlyn in Mountsbay, Cornwall, Boulmer near Alnwick (where almost all the inhabitants are called Stephenson, Stanton or Stewart), Burnmouth, Ross and (to some extent) Eyemouth in Berwickshire, Boyndie in Banffshire, Rathen in Aberdeenshire, Buckhaven in Fifeshire, Portmahomack and Balnabruach in Eastern Ross. In France may be mentioned the commune of Batz, near Le Broisic in Loire-Inferieur, many of the central cantons of Bretagne, and the singular society called Foreatines--supposed to be of Irish descent--living between St Arnaud and Bourges. Many other European examples might be mentioned, such as the Marans of Auvergne, a race of Spanish converted Jews accused of introducing syphilis into France; the Burins and Sermoyers, chiefly cattle-breeders, scattered over the department of Ain and especially in the arrondissement of Bourg-en-Bresse; the Vaqueros, shepherds in the Asturias Mountains; and the Jewish Chuetas of Majorca.

See Gilbert Malcolm Sproat's _Scenes and Studies of Savage Life_; Westermarck's _History of Human Marriage_ (1894); Lord Avebury's _Origin of Civilisation_ (1902); J.F. McLennan's _Primitive Marriage_ (1865).

ENDOR, an ancient town of Palestine, chiefly memorable as the abode of the sorceress whom Saul consulted on the eve of the battle of Gilboa, in which he perished (1 Sam. xxviii. 5-25). According to a psalmist (Ps. lxxxiii. 9) it was the scene of the rout of Jabin and Sisera. Although situated in the territory of the tribe of Issachar, it was assigned to Manasseh. In the time of Eusebius and Jerome Endor existed as a large village 5 m. south of Mount Tabor; there is still a poor village of the same name on the slope of Jebel Dahi, near which are numerous caves.

For a description of the locality see Stanley, _Sinai and Palestine_, p. 337.

ENDOSPORA, a natural group or class of the Sporozoa, consisting of the orders Myxosporidia, Actinomyxidia, Sarcosporidia and Haplosporidia, together with various insufficiently-known forms (Sero- and Exosporidia), regarded at present as Sporozoa _incertae sedis_. The distinguishing feature of the group is that the spore-mother-cells (pansporoblasts) arise in the interior of the body of the parent-individual; in other words, sporulation is endogenous. Another very general character--though not so universal--is that the adult trophozoite possesses more than one nucleus, usually many (i.e. it is multinucleate). In the majority of forms, though apparently not in all (e.g. certain Microsporidia), sporulation goes on coincidently with growth and trophic life. With regard to the origin of the group, the probability is greatly in favour of a Rhizopod ancestry. The entire absence, at any known period, of a flagellate or even gregariniform phase; on the other hand, the amoeboid nature of the trophozoites in very many cases together with the formation of pseudopodia; and, lastly, the simple endogenous spore-formation characteristic of the primitive forms,--are all points which support this view, and exclude any hypothesis of a Flagellate origin, such as, on the contrary, is probably the case in the Ectospora (q.v.).

1. Order Myxosporidia. The Myxosporidia, or, more correctly, the dense masses formed by their spores, were well known to the earlier zoological observers. The parasites in fishes were called by Muller "fish-psorosperms," a name which has stuck to them ever since, although, as is evident from the meaning of the term ("mange-seed"), Muller had little idea of the true nature of the bodies. Other examples, infesting silkworms, have also long been known as "Pebrine-corpuscles," from the ravaging disease which they produce in those caterpillars in France, in connexion with which Pasteur did such valuable work. The foundation of our present morphological and biological knowledge of the order was well laid by the admirable researches of Thelohan in 1895. In spite, however, of the contributions of numerous workers since then (e.g. Doflein, Cohn, Stempell and others), there are still one or two very important points, such as the occurrence of sexual conjugation, upon which light is required.

Occurrence and habitat.

Although pre-eminently parasites of fishes, Myxosporidia also occur, in a few cases, in other Vertebrates (frogs and reptiles); no instance of their presence in a warm-blooded Vertebrate has, however, yet been described. One suborder (the Microsporidia or Cryptocystes) is pretty equally distributed between fishes on the one hand and Invertebrates--chiefly, but not exclusively, Arthropods--on the other. The parasites are frequently the cause of severe and fatal illness in their hosts, and devastating epidemics of myxosporidiosis have often been reported (e.g. among carp and barbel in continental rivers, due to a _Myxobolus_, and among crayfish in France, to _Thelohania_).

The seat of the invasion and the mode of parasitism are extremely varied. Practically any organ or tissue may be attacked, excepting, apparently, the testis and cartilage and bone. In one instance at least (that of _Nosema bombycis_ of the silkworm) the parasites penetrate into the ova, so that true hereditary infection occurs, the progeny being born with the disease. The parasites may be either free in some lumen, such as that of the gall bladder or urinary bladder (not of the alimentary canal, or the body-cavity itself), when they are known as _coelozoic_ forms; or in intimate relation with some tissue, intracellular while young but becoming intercellular in the adult phase (_histozoic_ forms); or entirely intracellular (_cytozoic_ forms). Among the histozoic and cytozoic types, moreover, two well-defined conditions, _concentration_ and _diffuse infiltration_, occur. In the former, the parasitic zone is strictly limited, and well-marked cysts are formed; in the latter, the infection spreads throughout the neighbouring tissue, and the parasitic development becomes inextricably commingled with the host's cells. Sometimes, as shown by Woodcock (45), there may be an attempt on the part of the host's tissue to circumscribe and check the growth of these parasitic areas, which results in the formation of _pseudocysts_, quite different in character from true cysts.

[Illustration: From Lankester's _Treatise on Zoology_, vol. Protozoa, from Wasielewski, after Thelohan.

FIG. 1.--Transverse section of a stickle-back (_Gasterosteus aculeatus_), showing two cysts of _Glugea anomala_, Moniez (kk), in the body musculature on the right side.]

[Illustration: From Lankester's _Treatise on Zoology_, vol. Protozoa.

FIG. 2.--Portion of a section through a muscle fibre of _Cottus scorpius_ invaded by _Pleistophora typicalis_, Gurley. m, f, Muscle fibrils, retaining their striation. myx, Cysts of the parasite, lying between the fibrils.]

Morphology.

The most noticeable feature about the Myxosporidian trophozoite is its amoeboid and Rhizopod-like character. Pseudopodia of various kinds, from long slender ones (fig. 3, B) to short blunt lobose ones, are of general occurrence, being most easily observed, of course, in the free-living forms. The pseudopodia serve chiefly for movement and attachment, and never, it should be noted, for the injection of solid food-particles, as in the case of _Amoebae_. The general protoplasm is divisible into ectoplasm and endoplasm. The former is a clear, finely-granular layer, of which the pseudopodia are mainly constituted (fig. 3, A). In one or two instances (e.g. _Myxidium lieberkuhnii_) the ectoplasm shows a vertical striation, and in the older trophozoites breaks down partially, appearing like a fur of delicate, non-motile filaments. A somewhat similar modification is found in _Myxocystis_. The endoplasm is more fluid, and contains numerous inclusions of a granular nature, as well as vacuoles of varying size. In the endoplasm are lodged the nuclei, of which in an adult trophozoite there may be very many; they are all derived by multiplication from the single nucleus with which the young individuals begin life, the number increasing as growth proceeds.

[Illustration: From Wasielewski, _Sporozoenkunde_.

FIG. 3.--A. Trophozoite of _Sphaerospora divergens_, Thel. (par. _Blennius_ and _Crenilabrus_), X 750. ec, Ectoplasm; en, endoplasm; sp, spores, each with four pole capsules.

From Lankester's _Treatise on Zoology_, vol. Protozoa.

B. Spore-bearing trophozoite of Leptotheca agilis, Thel. (par. Trygon and Scorpaena), X 750. _ps_, Pseudopodia localized at the anterior end; f.gr, fatty granules similarly localized; r.gr, refringent granules; sp, spores, two in number.]

Spore-formation; multiplicative processes.

Spore-formation goes on entirely in the endoplasm. The number of spores formed is very variable. It may be as low as two (as in free-living forms, _e.g._ _Leptotheca_), in which case a large amount of trophic protoplasm is unconverted into spores; or, on the other hand, the number of spores may be very great (as in tissue-parasites), practically the whole of the parent-body being thus used up. The sporont may or may not encyst at the commencement of sporulation. In the free-living forms there is no cyst-membrane secreted; but in certain _Glugeidae_, on the other hand, the ectoplasm becomes altered into a firm, enclosing layer, the _ectorind_, which forms a thick cyst-wall (fig. 5). The process of sporulation begins by the segregation of small quantities of endoplasm around certain of the nuclei, to form little, rounded bodies, the _pansporoblasts_. There may be either very many or only few pansporoblasts developed; in some cases, indeed, there is only one, the sporont either itself becoming a pansporoblast (certain _Microsporidia_), or giving rise to a solitary one (_Ceratomyxidae_). The pansporoblast constituted, nuclear multiplication goes on preparatory to the formation of sporoblasts, which in their turn become spores (see figs. 4 and 5). Not all the nuclei thus formed, however, are made use of. In the _Phaenocystes_ there are always two sporoblasts developed in each pansporoblast; in the _Cryptocystes_ there may be from one to several. Around each sporoblast a spore-membrane is secreted, which usually has the form of two valves. It has recently been shown by Leger and Hesse (29b) that, in many Phaenocystes at any rate, each of these valves is formed by a definite nucleated portion of the sporoblast.

The spores themselves vary greatly in size and shape (figs. 7 and 8). They may be as small as 1.5 [mu] by 1 [mu] (as in a species of _Nosema_), or as large as 100 [mu] by 12 [mu] (as in _Ceratomyxa_). A conspicuous feature in the structure of a fully-developed spore is the polar-capsules, of which there may be either 1, 2, or 4 to each. In the Phaenocystes the polar-capsules are visible in the fresh condition, but not in the Cryptocystes. The polar-capsule is an organella which recalls the nematocyst of a Hydrozoan, containing a spirally-coiled filament, often of great length, which is shot out on the application of a suitable stimulus. Normally, as was ingeniously shown by Thelohan (43), the digestive juices of the fresh host serve this purpose, but various artificial means may suffice. The function of the everted filament is probably to secure the attachment of the spore to the epithelium of the new host. In the Phaenocystes, in connexion with each polar-capsule, a small nuclear body can be generally made out; these two little nuclei are those of the two "capsulogenous" areas of the protoplasm of the pansporoblast, which formed the capsules. The sporoplasm, representing the sporozoite, is always single. Nevertheless, in the Phaenocystes it is invariably binuclear; and, in the Microsporidia, the nucleus, at first single, gives rise later to four nuclei, two of which are regarded by Stempell (42) as corresponding to those of two polar-capsules (of which only one is developed in the spore), the remaining two representing germ-nuclei. Hence it is possible that the Myxosporidian sporoplasm really consists of two, incompletely-divided (sister) germs. Moreover, it is supposed by some that these two nuclei fuse together later, this act representing a sexual conjugation; since the earliest known phases of young trophozoites (amoebulae) have been described as uninuclear.

[Illustration: From Lankester's _Treatise on Zoology_, vol. Protozoa, after Thelohan.

FIG. 4.--Stages in spore-formation. All the figures are from _Myxobolus ellipsoides_, except a and f, which are from _M. pfeifferi_.

a, Differentiation of the pansporoblast (p.sp). b, Pansporoblast with two nuclei. c and d, Pansporoblasts with six and ten nuclei respectively; in d, four of the nuclei are degenerating. e, Pansporoblast segmented into two definitive sporoblasts, each with three nuclei. In the next four figures the definitive sporoblast, or the spore produced from it, is alone figured. f, Definitive sporoblast segmented into three masses, the capsulogenous cells (c.g.c) and the sporoplasm (sp.p), within an envelope, the spore membrane (sp.m). g, More advanced stage. h, Spore completely developed, with two polar capsules and sporoplasm containing an iodinophilous vacuole. i, Abnormal spore containing six polar capsules. n, Nuclei. sp.bl, Definitive sporoblast. r.n, Residuary nuclei. vac, Vacuole. r.p.c, Rudiment of p.c, polar capsule. n.p.c, Nuclei of polar capsules. iod.vac, Iodinophilous vacuole. n.sp, Nuclei of sporoplasm.]

[Illustration: From Woodcock, _Proc. and Trans. of the Liverpool Biological Society_, 1904.

FIG. 5.--Part of the periphery of a cyst of _Glugea stephani_, in the intestinal wall of the plaice, showing sporoblast and spore-formation.

ect, Ectorind. end, Endoplasm. endoth, Fold of the mucous membrane, normal in character. p.sp.bl, Various stages in the development of the pansporoblasts. sp, Ripe spores, filling the greater part of the cyst. n, Large (vegetative) nuclei.]

[Illustration: From Lankester's _Treatise on Zoology_, vol. Protozoa.

FIG. 6.--Formation of buds by multiple plasmotomy in _Myxidium lieberkuhnii_, Butschli (par. _Esox_ and _Lota_) after Cohn.

b, Buds. end, Endoplasm; the clear outer portion represents the ectoplasm.]

In addition to spore-formation, two or three modes of endogenous reproduction, serving for auto-infection, have been made known. One, termed by Doflein _plasmotomy_, consists either in the division of the (multinucleate) trophozoite into two, by more or less equal fission (simple plasmotomy), or in the budding-off, from the parent trophozoite, of several portions (example: _Myxidium lieberkuhnii_, fig. 6). A variety of this method has been described by Stempell (40) in the case of the young trophozoites (meronts) of _Thelohania mulleri_, which may divide into two while still uninuclear; and by rapid successive divisions chains of meronts may be formed, the different individuals being incompletely separated. Another method, which is probably chiefly responsible for the rapid spread of tissue-parasites and cell-parasites (such as _Myxobolidae_ and _Glugeidae_) through their host's tissue in the condition of diffuse infiltration, consists in multiple nuclear division, and the liberation of amoebulae while the parasite is yet quite young and possesses only few nuclei. As Woodcock has pointed out in considering the case of _Glugea stephani_, it is very probable that this "multiplicative reproduction," in diffuse infiltration, is to be looked upon as a separation of the pansporoblast-rudiments as daughter-individuals; i.e. that the pansporoblasts are, in certain circumstances, capable of independent existence as little sporonts. A further stage in this direction of evolution is seen, according to Stempell, in _Thelohania_, _Pleistophora_ and other types where the whole individual becomes one reproductive organella; such forms are to be considered as examples of a phylogenetic individualization of the pansporoblasts, which now exist as solitary sporonts. An extreme case of this "reduction of the individual" is found, apparently in the genus _Nosema_, as lately characterized by Perez (34), where vast numbers of minute entirely independent sporonts (pansporoblasts) are produced, each of which gives rise to only a single spore.

The Myxosporidia are divided into two suborders, the Phaenocystes and the Cryptocystes. Some authors have of late years separated these two divisions and raised each to the rank of a distinct order, considering that they are not more closely related to each other than to other Endosporan orders. We think this is a mistake; and it is very interesting to find that Leger and Hesse (1908) have described (29a) a new genus of Phaenocystes, _Coccomyxa_, which represents a type intermediate between these two suborders, and shows that they are closely connected.

Classification.

Suborder 1: _Phaenocystes_, Gurley. Spores relatively large, with generally two or four polar-capsules, visible in the fresh condition. There are nearly always two spores formed in each pansporoblast.

Section (a): _Disporea_. Only two spores (i.e. one pansporoblast) produced in each individual trophozoite. The greatest length of the spore is at right angles to the plane of the suture.

One family, _Ceratomyxidae_, including two genera, _Ceratomyxa_ (fig. 3, B) and _Leptotheca_, typically "free" parasites, mostly from the gall bladders of fishes. The valves of the spore in the former genus are prolonged into hollow cones. The type-species of this genus is _C. sphaerulosa_, from _Mustelus_ and _Galeus_; that of _Leptotheca_ is _L. agilis_, from _Trygon_.

Section (b): _Polysporea_. More than two spores, generally very many, are produced typically by each individual trophozoite. The greatest length of the spore is usually in the sutural plane.

Family, _Myxidiidae_. Spores with two polar-capsules, and without an iodinophilous vacuole in the sporoplasm. Mostly "free" parasites. Gen. _Sphaerospora_. Four or five species are known, from the kidneys or gall bladder of fishes (fig. 3, A). One, _S. elegans_, is interesting in that it affords a transition between the two sections, being disporous. Gen. _Myxidium_; spores elongated and fusiform, with a polar capsule at each extremity. The best-known species is _M. lieberkuhnii_, from the urinary bladder of the pike. One or two species occur in reptiles. Other genera are _Sphaeromyxa_, _Cystodiscus_, _Myxosoma_ and _Myxoproteus_.

Family, _Chloromyxidae_. Spores with four polar capsules and no iodinophilous vacuole. One genus, _Chloromyxum_, of which several species are known; the type being _C. leydigi_, from the gall bladder of various Elasmobranchs (fig. 7, B).

[Illustration: FIG. 7.--A. Spore of _Ceratomyxa sphaerulosa_, Thel. (par. _Mustelus_ and _Galeus_), X 750, after Thelohan. sp.p, Sporoplasm; p.c, polar capsules; s, suture; x, "irregular, pale masses, of undetermined origin."

From Lankester's _Treatise on Zoology_, vol. Protozoa.

B. Spores of _Chloromyxidae_, after Thelohan. a, _Chloromyxum leydigi_, Ming., seen from the sutural aspect, X 2250; b, _C. caudatum_, Thel., X 1900. p.c, Polar capsules; s, suture; f, filaments; p.s, tail-like process of the spore envelope.

From Wasielewski's _Sporozoenkunde_.

C. Spores of _Myxobolus ellipsoides_, Thel. The spores on the left and right are lying with the sutural plane horizontal, that in the middle with the sutural plane vertical.]

Family, _Myxobolidae_. Spores with two polar-capsules (exceptionally one), and with a characteristic iodinophilous vacuole in the sporoplasm. Typically tissue parasites of Teleosteans, often very dangerous. Genus _Myxobolus_. Spores oval or rounded, without a tail-like process. Very many species are known, which are grouped into three subsections: (a) forms with only one polar-capsule, such as _M. piriformis_, of the tench; (b) forms with two unequal capsules, e.g. _M. dispar_ from _Cyprinus_ and _Leuciscus_; and (c) the great majority of species with two equal polar-capsules, including _M. mulleri_, the type-species, from different fish, _M. cyprini_ and _M. pfeifferi_, the cause of deadly disease in carp and barbel respectively and others. Other genera are _Henneguya_ and _Hoferellus_, differing from _Myxobolus_ in having, respectively, one or two tail-like processes to the spore. _Lentospora_, according to Plehn (37), lacks an iodinophilous vacuole.

Family _Coccomyxidae_. The pansporoblasts produce (probably) only one spore. Spore oval, large (14 [mu] by 5.5 [mu]), with a single very large polar-capsule. Sporoplasm with no vacuole. Single genus _Coccomyxa_, with the characters of the family. One species, _C. morovi_, Leger and Hesse, from the gall bladder of the sardine. The spore greatly resembles a Cryptocystid spore.

Suborder 2: _Cryptocystes_, Gurley (= _Microsporidia_, Balbiani). Spores minute, usually pear-shaped, with only one polar-capsule, which is visible only after treatment with reagents. The number of spores formed in each pansporoblast varies greatly in different forms.

Section (a): _Polysporogenea_. The trophozoite produces numerous pansporoblasts, each of which gives rise to many spores. Genus _Glugea_, with numerous species, of which the best-known is _G. anomala_, from the stickleback (fig. 1). The genus _Myxocystis_, which has been shown by Hesse (24) to be a true Microsporidian, is placed by Perez in this section, but this is a little premature, as Hesse does not describe the exact character of the sporulation, i.e. with regard to the number of pansporoblasts and the spores they produce.

Section (b): _Oligosporogenea_. The trophozoite becomes itself the (single) pansporoblast. In _Pleistophora_, the pansporoblast produces many spores; _P. typicalis_, from the muscles of various fishes (fig. 2), is the type-species. In _Thelohania_, eight spores are formed; the different species are parasitic in Crustacea. In _Gurleya_, parasitic in _Daphnia_, only four are formed; and, lastly, in _Nosema_ (exs. _N. pulvis_, from _Carcinus_, and, most likely, _N. bombycis_, of the silkworm), each pansporoblast produces only a single spore.

2. Order--Actinomyxidia. This order comprises a peculiar group of parasites, first described by A. Stolc in 1899, which are restricted to Oligochaete worms of the family _Tubificidae_. Most forms attack the intestinal wall, often destroying its epithelium over considerable areas; but one genus, _Sphaeractinomyxon_, inhabits the body-cavity of its host. The researches of Caullery and Mesnil (10-12) and of Leger (28 and 29) have shown that the parasites exhibit the typical features of the Endospora, and the spores possess the characteristic polar-capsules of the Myxosporidian spore, but differ therefrom by their more complicated structure.

[Illustration: From Lankester's _Treatise on Zoology_, vol. Protozoa.

FIG. 8.--Spores of various _Glugeidae_, X 1500 (after Thelohan).

a and b, _Pleistophora typicalis_, Gurley; a in the fresh condition, b after treatment with iodine water, causing extrusion of the filament. c and d, _Thelohania octospora_, Henneguy; c fresh, d treated with ether. e, _Glugea depressa_, Thel., fresh. f, _G. acuta_, Thel.]

The growth and development of an Actinomyxidian have been recently worked out by Caullery and Mesnil in the case of _Sphaeractinomyxon stolci_. A noteworthy point is the differentiation of an external (covering) cellular layer, which affords, perhaps, the nearest approach to distinct tissue-formation known among Protozoa. This envelope is formed soon after nuclear multiplication of the young trophozoite has begun, and is constituted by two nuclei and a thin, peripheral layer of cytoplasm. It remains binuclear throughout the entire period of development, and serves as a delicate cyst-membrane. The multiplication of the internal nuclei is accompanied by a corresponding division of the cytoplasm; so that instead of a multinucleate or plasmodial condition, distinct uninucleate cellules are formed, up to sixteen in number. These cellules, as a matter of fact, are sexual elements or gametes; and eight of them can be distinguished from the other eight by slight differences in the nuclei. The gametes unite in couples, each couple being most probably composed of dissimilar members: in other words, conjugation is slightly anisogamous. Each of these eight copulae gives rise to a spore.

As the name of the order implies, there are always eight spores formed. These differ from other Endosporan spores in having invariably a ternary symmetry and constitution (fig. 9). The wall of the spore is composed of three valves, each formed from an enveloping cell, and three capsular cells, placed at the upper or anterior pole, and containing each a polar-capsule, visible in the fresh condition. The valves are usually prolonged into processes or appendages, whose form and arrangement characterize the genus; but in _Sphaeractinomyxon_ the spore is spherical and lacks processes. The sporoplasm may be either a plasmodial mass, with numerous nuclei, or may form a certain number of uninuclear sporozoites. A remarkable feature in the development of the spore is that the germinal tissue (sporoplasm) arises separate from and outside the cellules which give rise to the spore-wall; later, when the envelopes are nearly developed, the sporoplasm penetrates into the spore.

Four genera have been made known. (1) _Hexactinomyxon_, Stolc. Spores having the form of an anchor with six arms; sporoplasm plasmodial, situate near the anterior pole of the spore. One sp. _H. psammoryctis_, from _Psammoryctes_. (2) _Triactinomyxon_, St. Spores having the form of an anchor with three arms; distinct sporozoites, disposed near the anterior pole. _T. ignotum_, with eight spores, from _Tubifex tubifex_, and also from an unspecified Tubificid; another sp., unnamed, with 32 sporozoites, also from T. t. (3) _Synactinomyxon_, St. Spores united to one another, each having two aliform appendages; sporoplasm plasmodial. One sp., _S. tubificis_, from _T. rivulorum_. (4) _Sphaeractinomyxon_, C. and M. Spores spherical, without aliform prolongations; sporoplasm gives rise to very many sporozoites, occupying the whole spore. One sp., _S. st_olci, from _Clitellio_ and _Hemitubifex_.

[Illustration: From Lankester's _Treatise on Zoology_, vol. Protozoa.

FIG. 9.--Spores of Actinomyxidia (after Stolc).

a, _Hexactinomyxon psammoryctis_ (par. _Psammoryctes barbatus_). b, _Synactinomyxon tubificis_ (par. _Tubifex rivulorum_); the mass of united spores. c, _Triactinomyxon ignotum_ (par. _Clitellio_, sp.). d, Upper portion of _Hexactinomyxon_, showing two of the three polar capsules, one with filament discharged.]

[Illustration: From Wasielewski's _Sporozoenkunde_.

FIG. 10.--A. Sarcosporidia in the ox; a transverse section of the oesophagus, natural size, showing the parasites in the outer (a, b, c, d, e) and inner (f, g, h) muscular coats.

B. Longitudinal section of a muscle-fibre containing a Sarcosporidian parasite, X 60.]

3. Order--Sarcosporidia. With the exception of one or two forms occurring in reptiles, these parasites are always found in warm-blooded Vertebrates, usually Mammals. They are of common occurrence in domestic animals, such as pigs, sheep, horses and (sometimes) cattle. A Sarcosporidian has also been described from man. The characteristic habitat is the striped muscle, generally of the oesophagus (fig. 10, A) and heart, but in acute cases the parasites overrun the general musculature. When this occurs, as often happens in mice, the result is usually fatal. Unless, however, the organisms thus spread throughout the body, the host does not appear to suffer any serious consequences. In addition to the effects produced by the general disturbance to the tissues, the attacked animals have apparently to contend--at any rate in the case of _Sarcocystis tenella_ in the sheep--with a poison secreted by the parasite. For Laveran and Mesnil (27) have isolated a toxine from this form, which they have termed sarcocystin.

In the early stages of growth, a Sarcosporidian appears as an elongated whitish body lodged in the substance of a muscle-fibre; this phase has long been known as a "Miescher's tube," or _Miescheria_. The youngest trophozoites that have been yet observed (by Bertram, 1) were multinucleate (fig. 11, A), but there is no reason to doubt that they begin life in a uninuclear condition. The protoplasm is limited by a delicate cuticle. With growth, organellae corresponding to the Myxosporidian pansporoblasts are formed by the segregation internally of little uninuclear spheres of protoplasm. At the same time, a thick striated envelope is developed around the parasite, which later comes to look like a fur of fine filaments. The probable explanation of this feature (given by Vuillemin, 44) is that it is due to the partial breaking down of a stiff, vertically (or radially) striated external layer (fig. 12, A), such as is seen in _Myxidium lieberkuhnii_. Immediately internal to this is a thin, homogeneous membrane, which sends numerous partitions or septa inwards; these divide up the endoplasm into somewhat angular chambers or alveoli (fig. 12). In each chamber is a pansporoblast, which divides up to produce many spores; hence the spores formed from different pansporoblasts are kept more or less separate. The pansporoblasts originate, in a growing Sarcosporidian, at the two poles of the body, where the peripheral endoplasm with its nuclei is chiefly aggregated. More internally, spore-formation is in progress; and in the centre, pansporoblasts full of ripe spores are found.

By this time the parasite has greatly distended the muscle-fibre in which it has hitherto lain, absorbing, with its growth, practically all the contractile-substance, until it is surrounded only by the sarcolemma and sarcoplasm. It next passes into the adjacent connective-tissue, and in this phase has been distinguished from _Miescheria_ as _Balbiania_, under the impression that the two forms were quite distinct. In the later stages, the parasite may become more rounded, and a cyst may be secreted around it by the host's tissue. In these older forms, the most centrally placed spores degenerate and die, having become over-ripe and stale.

[Illustration: After Bertram, from Wasielewski's _Sporozoenkunde_.

FIG. 11.--Stages in the growth of _Sarcocystis tenella_ of the sheep. A, Youngest observed stage in which the radially striated outer coat has not appeared; the body of the trophozoite is already divided into a number of cells or pansporoblasts (k). B and C, Older stages with numerous pansporoblasts and two envelopes, an inner membrane and an outer radially striated layer.]

With regard to the spores themselves and what becomes of them, our knowledge is defective. Two kinds of reproductive germ have been described, termed respectively _gymnospores_ (so-called sporozoites, "Rainey's corpuscles") and _chlamydospores_, or simply spores. It seems probable that the former serve for endogenous or auto-infection, and the latter for infecting fresh hosts. Unfortunately, however, both kinds of germ are not yet known in the case of any one species. The gymnospores, which are the more commonly found (e.g. in _S. muris_, _S. miescheriana_ of the pig, and other forms), are small sickle-shaped or reniform bodies which are more or less amoeboid, and capable of active movement at certain temperatures. They appear to be naked, and consist of finely granular protoplasm, containing a single nucleus and one or two vacuoles. The chlamydospores, or true spores, occur in _S. tenella_ of sheep (fig. 13), and have been described by Laveran and Mesnil (26). They also are falciform, but one extremity is rounded, the other pointed. There is a very thin, delicate membrane, most unlike a typical, resistant spore-wall; and the spores themselves are extremely fragile and easily acted upon and deformed by reagents, even by distilled water. The rounded end of the spore contains a large nucleus, while at the other end is an oval, clear space, which, in the fresh condition, shows a distinct spiral striation. The exact significance of this structure has been much debated. In position and appearance it recalls the polar-capsule of a Myxosporidian spore. The proof of this interpretation would be the expulsion of a filament on suitably stimulating the spore; while, however, some investigators have asserted that such a filament is extruded, this cannot be regarded as at all certain. Hence it is still doubtful whether this striated body really corresponds to a polar-capsule.

[Illustration: From Wasielewski's _Sporozoenkunde_.

_Fig._ 12.--A, _Sarcocystis miescheriana_ (Kuhn) from the pig: late stage in which the body has become divided up into numerous chambers or alveoli, each containing a number of germs.

B, _Sarcocystis_ of the ox: section of a stage similar to fig. 12. a, Substance of muscle-fibre; b, envelope of parasite; c, nuclei of the muscle; d, parasitic germs (gymnospores); e, walls of the alveoli. In the peripheral alveoli are seen immature germs.]

[Illustration: (After Laveran and Mesnil, from Lankester's _Treatise on Zoology_, vol. Protozoa.)

FIG. 13.--Spores of _Sarcocystis tenella_, Raill., from the sheep.

a, Spore in the fresh condition, showing a clear nucleus (n) and a striated body or capsule (c). b, Stained spore; the nucleus (n) shows a central karyosome; the striations of the polar capsule (c) are not visible.]

Nothing whatever is known as to the natural means by which infection with Sarcosporidia is brought about. Smith (39) showed that mice can be infected with _Sarcocystis muris_ by simply feeding them on the flesh of infected mice. It is not very likely, however, that this represents the natural mode, even in the case of mice; and it certainly cannot do so in the case of Herbivora. The difficulty in the way is the delicacy of the spores, which seem totally unfitted to withstand external conditions. It may be that some alternative (intermediate) host is concerned in dispersal; but this has yet to be ascertained.

All known Sarcosporidia are included in a single genus _Sarcocystis_, Lank. (= _Miescheria_ + _Balbiania_, Blanchard.) Some of the principal species are: _S. miescheriana_, from pigs; _S. tenella_, from sheep; _S. bertrami_, from horses; _S. blanchardi_, from Bovines; _S. muris_, from mice; _S. platydactyli_, from the gecko; and lastly, _S. lindemanni_, described from man.

4. Order--Haplosporidia. The Sporozoa included in this order are characterized by the general simplicity of their development, and by the undifferentiated character of their spores. The order includes a good many forms, whose arrangement and classification have been recently undertaken by Caullery and Mesnil (15), to whom, indeed, most of our knowledge relating to the Haplosporidia is due. The habitat of the parasites is sufficiently varied; Rotifers, Crustacea, Annelids and fishes furnishing most of the hosts. A recent addition to the list of Protozoa causing injury to man, a Haplosporidian, has been described by Minchin and Fantham (29d), who have termed the parasite _Rhinosporidium_, from its habitat in the nasal septum, where it produces pedunculate tumours.

[Illustration: From Minchin, in Lankester's _Treatise on Zoology_, vol. Protozoa.

FIG. 14.--_Bertramia Asperospora_ (Fritsch) from the body-cavity of _Brachionus_. X 1040.

a, Young form with opaque, evenly-granulated protoplasm and few refringent granules; the nuclei (n) are small, and appear to be surrounded each by a clear space. b and c, Full-grown specimens with large nuclei and clearer protoplasm, containing numerous refringent granules (r. gr.). d and e, Morula stages, derived from b and c by division of the body into segments centred round the nuclei, each cell so formed being a spore. Between the spores a certain amount of intercellular substance or residual protoplasm is left, in which the refringent granules seem to be embedded. The morula may break up forthwith and scatter the spores, or may first round itself off and form a spherical cyst with a tough, fairly thick wall. f, Empty, slightly shrunken cyst, from which the spores have escaped. g, Free spore or youngest unicellular trophozoite. h, i, j, Commencing growth of the trophozoite, with multiplication of the nuclei, which results ultimately in forms such as a and b.]

_Bertramia_, a well-known parasite of the body-cavity of Rotifers, will serve very well to give a general idea of the life-cycle so far as it has yet been made out (fig. 14). The trophozoite begins life as a small, rounded uninucleate corpuscle, which as it grows, becomes multinucleate. The multinuclear body generally assumes a definite shape, often that of a sausage. Later, the protoplasm becomes segregated around each of the nuclei, giving the parasite a mulberry-like aspect; hence this stage is frequently known as a morula. The uninuclear cellules thus formed are the spores, which are ultimately liberated by the break-up of the parent body. Each is of quite simple, undifferentiated structure, possesses a large, easily-visible nucleus, and gives rise in due course to another young trophozoite. In some instances, as described by Minchin, the sporulating parasite becomes rounded off and forms a protective cyst, doubtless for the protection of the spores during dissemination.

In some forms (e.g. _Haplosporidium_ and _Rhinosporidium_) the spore-mother-cells, instead of becoming each a single spore, as in _Bertramia_, give rise to several, four in the first case, many in the latter. Sometimes, again, the spore, while preserving the essentially simple character of the sporoplasm, may be enclosed in a spore-case; this may have the form of a little box with a lid or operculum, as in some species of _Haplosporidium_, or may possess a long process or tail, as in _Urosporidium_ (fig. 15).

[Illustration: From Caullery and Mesnil, _Archives de zoologie experimentale_, vol. 4, 1905, by permission of Schleicher Freres et Cie, Paris.

FIG. 15.--Spores of various Haplosporidia.

1. _Haplosporidium heterocirri_: a, on liberation; b, after being in sea-water. 2, _H. scolopli_. 3, _H. vejdovskii_. 4, _Urosporidium fuliginosum_: a, surface-view; b, side-view. X 1000.]

The _Haplosporidia_ are divided by Caullery and Mesnil into three families, _Haplosporidiidae_, _Bertramiidae_ and _Coelosporidiidae_; one or two genera are also included whose exact position is doubtful.

(a) _Haplosporidiidae_: 3 genera, _Haplosporidium_, type-species _H. heterocirri_; _Urosporidium_, with one sp., _U. fuliginosum_; all parasitic in various Annelids; and _Anurosporidium_, with the species _A. pelseneeri_, from the sporocysts of a Trematode, parasitic on _Donax_.

(b) _Bertramiidae_: 2 genera, _Bertramia_, with _B. capitellae_ from an Annelid and _B. asperospora_, the Rotiferan parasite above described; and _Ichthyosporidium_, with _I. gasterophilum_ and _I. phymogenes_, parasitic in various fish.

(c) _Coelosporidiiae_: genera _Coelosporidium_, type-species _C. chydoriclola_; and _Polycaryum_, type-species _P. branchiopodianum_. These forms are parasitic in small Crustacea. The genus _Blastulidium_ is referred, doubtfully, by Caullery and Mesnil to this family; but certain phases of this organism seem to indicate rather a vegetable nature.

The genus _Rhinosporidium_ should probably be placed in a distinct family. The only species so far described is _R. kinealyi_ from the nasal septum of man, to which reference has above been made. Another form, _Neurosporidium cephalodisci_, agreeing in some respects with _Rhinosporidium_, has been described by Ridewood and Fantham (37a) from the nervous system of _Cephalodiscus_.

A parasite whose affinities are doubtful, but which is regarded by Caullery and Mesnil as allied to the Haplosporidia, is the curious parasite originally described by Schewiakoff as "endoparasitic tubes" of _Cyclops_; it has been named by Caullery and Mesnil, _Scheviakovella_. This organism is remarkable in one or two ways: it possesses a contractile vacuole; the amoeboid trophozoites tend to form plasmodia; and the spores, of the usual simple type, may apparently divide by binary fission.

5. There remain, lastly, certain forms, which are conveniently grouped together as "Sporozoa _incertae sedis_," either for the reason that it is impossible to place them in any of the well-defined orders, or because their life-cycle is at present too insufficiently known. Serosporidia is the name given by Pfeiffer to certain minute parasites of the body-cavity of Crustacea; they include _Serosporidium_, _Blanchardina_ and _Botellus_. _Lymphosporidium_, a form with distributed nucleus, causing virulent epidemics among brook-trout, is considered by Calkins(3) to be suitably placed here. Another parasite of lymphatic spaces and channels is the remarkable _Lymphocystis_, described by Woodcock (46), from plaice and flounders, which in some respects rather recalls a Gregarine. The group Exosporidia was founded by Perrier to include a peculiar organism, ectoparasitic on Arthropods, to which the name of _Amoebidium_ had been given by Cienkowsky. It has recently been shown, however, that this organism is most probably an Alga. Another genus, _Exosporidium_, described by Sand (38), is placed at present in this group. For details of the structure of these forms and others like _Siedleckia_, _Toxosporidium_, _Chitonicium_ _Joyeuxella_ and _Metschnikovella_, a comprehensive treatise on the Sporozoa, such as that of Minchin, should be consulted.

To complete this article, it will be sufficient to mention various enigmatical bodies, associated with different diseases, which are regarded by their describers as Protozoa. Among such is the "_Histosporidium carcinomatosum_" of Feinberg, which he finds in cancerous growths. _Cytoryctes_, the name given to "Guarnieri's bodies" in small-pox and vaccinia, has been recently investigated by Calkins (3a), who has described a complex life-cycle for the alleged parasite. Other workers, however, such as Siegel, give a quite different account of these bodies, and, moreover, find similar ones in scarlet-fever, syphilis, &c.; while yet others (e.g. Prowazek) deny that they are parasitic organisms at all.

BIBLIOGRAPHY.--(For general works see under SPOROZOA.) (1) Bertram, "Beitrage zur Kenntnis der Sarcosporidien," _Zool. Jahrb. Anat._ 5, 1902; (2) L. Brasil, "Joyeuxella toxoides," (n.g., n.sp.), _Arch. zool. exp._ N. et R. (3) 10, p. 5, 7 figs., 1902; (3) G.N. Calkins, "Lymphosporidium truttae," (n.g., n.sp.), _Zool. Anz_. 23, p. 513, 6 figs., 1903; (3a) ib. _The Life-History of Cytoryctes Variolae_; Guarnieri, "Studies path. etiol. variola," _J. Med. Research_ (Boston, 1904), p. 136, 4 pls.; (3b) M. Caullery and A. Chappellier, "Anurosporidium pelseneeri, (n.g., n.sp.), Haplosporidie," &c., _C. R. soc. biol._ 60, p. 325, 1906; (4) M. Caullery and F. Mesnil, "Sur un type nouveau" (_Metchnikovella_, n.g.), _C. R. ac. sci._ 125, p. 787, 10 figs., 1897; (5) ib. "Sur trois Sporozoaires parasites de la Capitella," _C. R. soc. biol_. 49, p. 1005, 1877; (6) ib. "Sur un Sporozoaire aberrant" (_Siedleckia_, n.g.), op. cit. 50, p. 1093, 7 figs., 1898; (7) ib. "Sur le genre Aplosporidium" (nov.), op. cit. 51, p. 789, 1899; (8) ib. "Sur les Aplosporidies," _C. R. ac. sci._ 129, p. 616, 1899; (9) ib. "Sur les parasites intimes des Annelides" (_Siedleckia_, _Toxosporidium_), C. R. ass. franc., 1899, p. 491, 1900; (10) ib. "Sur un type nouveau (_Sphaeractinomyxon_, n.g.) d'Actinomyxidies," _C. R. soc. biol._ 56, p. 408, 1904; (11) ib. "Phenomenes de sexualite dans le developpement des Actinomyxidies," op. cit. 58, p. 889, 1905; (12) ib. "Recherches sur les

## Actinomyxidies," _Arch. Protistenk._ 6, p. 272, pl. 15, 1905; (13) ib.

"Sur quelques nouvelles Haplosporidies d'Annelides," C. R. soc. biol. 58, p. 580, 6 figs., 1905; (14) ib. "Sur des Haplosporidies parasites de poissons marins," ib. p. 640, 1905; (15) ib. "Recherches sur les Haplosporidies," _Arch. zool. exp._ (4) 4, p. 101, pls. 11-13, 1905; (16) L. Cohn, "Uber die Myxosporidien von Esox lucius," _Zool. Jahr. Anat_. 9, p. 227, 2 pls., 1896; (17) ib. "Zur Kenntniss der Myxosporidien," Centrbl. Bakt. 1, Orig. 32, p. 628, 3 figs., 1902; (18) ib. "Protozoen als Parasiten in Rotatorien," Zool. Anz. 25, p. 497, 1902; (19) F. Doflein, "Uber Myxosporidien," Zool. Jahr. Anat. 11, p. 281, 6 pls., 1898; (20) ib. "Fortschritte auf dem Gebiete der Myxosporidienkunde," _Zool. Centrbl_. 7, p. 361, 1899; (21) R. Gurley, "The Myxosporidia," _Bull. U.S. Fish. Comm., 1892_, p. 65, 47 pls., 1894; (22) E. Hesse, "Sur une nouvelle Microsporidie tetrasporee du genre Gurleya," _C. R. soc. biol._ 55, p. 495, 1903; (23) ib. "Thelohania legeri" (n.sp.), op. cit. 57, pp. 570-572, 10 figs., 1904; (24) ib. "Sur Myxocystis Mrazeki Hesse," &c., op. cit. 58, p. 12, 9 figs., 1905; (25) A. Laveran and F. Mesnil, "Sur la multiplication endogene des Myxosporidies," op. cit. 54, p. 469, 5 figs., 1902; (26) ib. "Sur la morphologie des Sarcosporidies," op. cit. 51, p. 245, 1899; (27) ib. "De la Sarcocystin," op. cit. p. 311, 1899; (28) L. Leger, "Sur la sporulation du Triactinomyxon," op. cit. 56, p. 844, 4 figs., 1904; (29) ib. "Considerations sur ... les Actinomyxidies," op. cit. p. 846, 1904; (29a) L. Leger and E. Hesse, "Sur une nouvelle Myxosporidie, Coccomyxa, n.g.," _C. R. ac. sci._, 1st July 1907; (29b) ib. "Sur la structure de la paroisporale des Myxosporidies," op. cit. 142, p. 720, 1906; (29c) A. Lutz and A. Splendore, "Uber 'Pebrine' and verwandte Mikrosporidien," _Centrbl. Bakt_. 1, 33, Orig. p. 150, 1903, and 36, Orig. p. 645, 2 pls., 1904; (29d) E.A. Minchin and H.B. Fantham, "Rhinosporidium kinealyi" (n.g., n.sp.), _Q. J. Micr. Sci._ 49, p. 521, 2 pls., 1905; (30) A. Mrazek, "Uber eine neue Sporozoenform" (_Myxocystis_), _S. B. Bohm. Ges._ 8, 5 pp., 9 figs., 1897; (31) ib. "Glugea lophii," Doflein, op. cit. 10, 8 pp., 1 pl., 1899; (32) C. Perez, "Sur un organisme nouveau, Blastulidium," _C. R. soc. biol._ 55, p. 715, 5 figs., 1903; (33) ib. "Sur nouvelles Glugeidees," op. cit. 58, pp. 146-151, 1905; (34) ib. "Microsporidies parasites des crabes," _Bull. sta. biol. d'Arcachon_, 8, 22 pp., 14 figs., 1905; (35) W.S. Perrin, "Pleistophora periplanetae," _Q. J. Micr. Sci._ 49, p. 615, 2 pls., 1906; (36) L. Plate, "Uber einen einzelligen Zellparasiten" (_Chitonicium_), _Fauna Chilensis_, 2, pp. 601, pls., 1901; (37) M. Plehn, "Uber die Drehkrankheit der Salmoniden" (_Lentospora_, n.g.), _Arch. Protistenk_. 5, p. 145, pl. 5, 1904; (37a) W.J. Ridewood and H.B. Fantham, "Neurosporidium cephalodisci, n.g., n.sp.," _Q. J. Micr. Sci._ 51, p. 81, pl. 7, 1907; (38) R. Sand, "Exosporidium marinum" (n.g., n.sp.), _Bull. soc. micr. belge_, 24, p. 116, 1898; (39) T. Smith, "The production of sarcosporidiosis in the mouse," &c., _J. Exp. Med._ 6, p. 1, 4 pls., 1901; (40) W. Stempell, "Uber Thelohania mulleri," _Zool. Jahr. Anat._ 16, p. 235, pl. 25, 1902; (41) ib. "Uber Polycaryum branchiopodianum" (n.g., n.sp.), _Zool. Jahrb. Syst._ 15, p. 591, pl. 31, 1902; (42) ib. "Uber Nosema anomalum," _Arch. Protistenk_, 4, p. 1, pls. 1-3, 1904; (43) P. Thelohan, "Recherches sur les Myxosporidies," _Bull. sci. France belg._ 26, p. 100, 3 pls., 1895; (44) P. Vuillemin, "Le Sarcocystis tenella, parasite de l'homme," _C. R. ac. sci._ 134, p. 1152, 1902; (45) H.M. Woodcock, "On Myxosporidia in flat fish," _Proc. Liverp. Biol. Soc._ 18, p. 126, pl. 2, 1904; (46) ib. "On a remarkable parasite" (_Lymphocystis_), op. cit. p. 143, pl. 3, 1904. (H. M. Wo.)

ENDYMION, in Greek mythology, son of Aethlius and king of Elis. He was loved by Selene, goddess of the moon, by whom he had fifty daughters, supposed to represent the fifty moons of the Olympian festal cycle. In other versions, Endymion was a beautiful youth, a shepherd or hunter whom Selene visited every night while he lay asleep in a cave on Mount Latmus in Caria (Pausanias v. 1; Ovid, _Ars am._ iii. 83). Zeus left him free to choose anything he might desire, and he chose an everlasting sleep, in which he might remain youthful for ever (Apollodorus i. 7). According to others, Endymion's eternal sleep was a punishment inflicted by Zeus upon him because he ventured to fall in love with Hera, when he was admitted to the society of the Olympian gods (Schol. Theocritus iii. 49). The usual form of the legend, however, represents Endymion as having been put to sleep by Selene herself in order that she might enjoy his society undisturbed (Cicero, _Tusc. disp._ i. 38). Some see in Endymion the sun, setting opposite to the rising moon, the Latmian cave being the cave of forgetfulness, into which the sun plunges beneath the sea; others regard him as the personification of sleep or death (see Mayor on Juvenal x. 318).

ENERGETICS. The most fundamental result attained by the progress of physical science in the 19th century was the definite enunciation and development of the doctrine of energy, which is now paramount both in mechanics and in thermodynamics. For a discussion of the elementary ideas underlying this conception see the separate heading ENERGY.

Ever since physical speculation began in the atomic theories of the Greeks, its main problem has been that of unravelling the nature of the underlying correlation which binds together the various natural agencies. But it is only in recent times that scientific investigation has definitely established that there is a quantitative relation of simple equivalence between them, whereby each is expressible in terms of heat or mechanical power; that there is a certain measurable quantity associated with each type of physical activity which is always numerically identical with a corresponding quantity belonging to the new type into which it is transformed, so that the energy, as it is called, is conserved in unaltered amount. The main obstacle in the way of an earlier recognition and development of this principle had been the doctrine of caloric, which was suggested by the principles and practice of calorimetry, and taught that heat is a substance that can be transferred from one body to another, but cannot be created or destroyed, though it may become latent. So long as this idea maintained itself, there was no possible compensation for the destruction of mechanical power by friction; it appeared that mechanical effect had there definitely been lost. The idea that heat is itself convertible into power, and is in fact energy of motion of the minute invisible parts of bodies, had been held by Newton and in a vaguer sense by Bacon, and indeed long before their time; but it dropped out of the ordinary creed of science in the following century. It held a place, like many other anticipations of subsequent discovery, in the system of Natural Philosophy of Thomas Young (1804); and the discrepancies attending current explanations on the caloric theory were insisted on, about the same time, by Count Rumford and Sir H. Davy. But it was not till the actual experiments of Joule verified the same exact equivalence between heat produced and mechanical energy destroyed, by whatever process that was accomplished, that the idea of caloric had to be definitely abandoned. Some time previously R. Mayer, physician, of Heilbronn, had founded a weighty theoretical argument on the production of mechanical power in the animal system from the food consumed; he had, moreover, even calculated the value of a unit of heat, in terms of its equivalent in power, from the data afforded by Regnault's determinations of the specific heats of air at constant pressure and at constant volume, the former being the greater on Mayer's hypothesis (of which his calculation in fact constituted the verification) solely on account of the power required for the work of expansion of the gas against the surrounding constant pressure. About the same time Helmholtz, in his early memoir on the Conservation of Energy, constructed a cumulative argument by tracing the ramifications of the principle of conservation of energy throughout the whole range of physical science.

_Mechanical and Thermal Energy._--The amount of energy, defined in this sense by convertibility with mechanical work, which is contained in a material system, must be a function of its physical state and chemical constitution and of its temperature. The change in this amount, arising from a given transformation in the system, is usually measured by degrading the energy that leaves the system into heat; for it is always possible to do this, while the conversion of heat back again into other forms of energy is impossible without assistance, taking the form of compensating degradation elsewhere. We may adopt the provisional view which is the basis of abstract physics, that all these other forms of energy are in their essence mechanical, that is, arise from the motion or strain of material or ethereal media; then their distinction from heat will lie in the fact that these motions or strains are simply co-ordinated, so that they can be traced and controlled or manipulated in detail, while the thermal energy subsists in irregular motions of the molecules or smallest portions of matter, which we cannot trace on account of the bluntness of our sensual perceptions, but can only measure as regards total amount.

_Historical: Abstract Dynamics._--Even in the case of a purely mechanical system, capable only of a finite number of definite types of disturbance, the principle of the conservation of energy is very far from giving a complete account of its motions; it forms only one among the equations that are required to determine their course. In its application to the kinetics of invariable systems, after the time of Newton, the principle was emphasized as fundamental by Leibnitz, was then improved and generalized by the Bernoullis and by Euler, and was ultimately expressed in its widest form by Lagrange. It is recorded by Helmholtz that it was largely his acquaintance in early years with the works of those mathematical physicists of the previous century, who had formulated and generalized the principle as a help towards the theoretical dynamics of complex systems of masses, that started him on the track of extending the principle throughout the whole range of natural phenomena. On the other hand, the ascertained validity of this extension to new types of phenomena, such as those of electrodynamics, now forms a main foundation of our belief in a mechanical basis for these sciences.

In the hands of Lagrange the mathematical expression for the manner in which the energy is connected with the geometrical constitution of the material system became a sufficient basis for a complete knowledge of its dynamical phenomena. So far as statics was concerned, this doctrine took its rise as far back as Galileo, who recognized in the simpler cases that the work expended in the steady driving of a frictionless mechanical system is equal to its output. The expression of this fact was generalized in a brief statement by Newton in the _Principia_, and more in detail by the Bernoullis, until, in the analytical guise of the so-called principle of "virtual velocities" or virtual work, it finally became the basis of Lagrange's general formulation of dynamics. In its application to kinetics a purely physical principle, also indicated by Newton, but developed long after with masterly applications by d'Alembert, that the reactions of the infinitesimal parts of the system against the accelerations of their motions statically equilibrate the forces applied to the system as a whole, was required in order to form a sufficient basis, and one which Lagrange soon afterwards condensed into the single relation of Least Action. As a matter of history, however, the complete formulation of the subject of abstract dynamics actually arose (in 1758) from Lagrange's precise demonstration of the principle of Least Action for a particle, and its immediate extension, on the basis of his new Calculus of Variations, to a system of connected

## particles such as might be taken as a representation of any material

system; but here too the same physical as distinct from mechanical considerations come into play as in d'Alembert's principle. (See DYNAMICS: _Analytical_.)

It is in the cases of systems whose state is changing so slowly that reactions arising from changing motions can be neglected, that the conditions are by far the simplest. In such systems, whether stationary or in a state of steady motion, the energy depends on the configuration alone, and its mathematical expression can be determined from measurement of the work required for a sufficient number of simple transformations; once it is thus found, all the statical relations of the system are implicitly determined along with it, and the results of all other transformations can be predicted. The general development of such relations is conveniently classed as a separate branch of physics under the name _Energetics_, first invented by W.J.M. Rankine; but the essential limitations of this method have not always been observed. As regards statical change, the complete specification of a mechanical system is involved in its geometrical configuration and the function expressing its mechanical energy in terms thereof. Systems which have statical energy-functions of the same analytical form behave in corresponding ways, and can serve as models or representations of one another.

_Extension to Thermal and Chemical Systems._--This dominant position of the principle of energy, in ordinary statical problems, has in recent times been extended to transformations involving change of physical state or chemical constitution as well as change of geometrical configuration. In this wider field we cannot assert that mechanical (or available) energy is never lost, for it may be degraded into thermal energy; but we can use the principle that on the other hand it can never spontaneously increase. If this were not so, cyclic processes might theoretically be arranged which would continue to supply mechanical power so long as energy of any kind remained in the system; whereas the irregular and uncontrollable character of the molecular motions and strains which constitute thermal energy, in combination with the vast number of the molecules, must place an effectual bar on their unlimited co-ordination. To establish a doctrine of _energetics_ that shall form a sufficient foundation for a theory of the trend of chemical and physical change, we have, therefore, to impart precision to this motion of available energy.

_Carnot's Principle: Entropy._--The whole subject is involved in the new principle contributed to theoretical physics by Sadi Carnot in 1824, in which the far-reaching modern conception of cyclic processes was first scientifically developed. It was shown by Carnot, on the basis of certain axioms, whose theoretical foundations were subsequently corrected and strengthened by Clausius and Lord Kelvin, that a reversible mechanical process, working in a cycle by means of thermal transfers, which takes heat, say H1, into the material system at a given temperature T1, and delivers the part of it not utilized, say H2, at a lower given temperature T2, is more efficient, considered as a working engine, than any other such process, operating between the same two temperatures but not reversible, could be. This relation of inequality involves a definite law of equality, that the mechanical efficiencies of all reversible cyclic processes are the same, whatever be the nature of their operation or the material substances involved in them; that in fact the efficiency is a function solely of the two temperatures at which the cyclically working system takes in and gives out heat. These considerations constitute a fundamental general principle to which all possible slow reversible processes, so far as they concern matter in bulk, must conform in all their stages; its application is almost coextensive with the scope of general physics, the special kinetic theories in which inertia is involved, being excepted. (See THERMODYNAMICS.) If the working system is an ideal gas-engine, in which a perfect gas (known from experience to be a possible state of matter) is passed through the cycle, and if temperature is measured from the absolute zero by the expansion of this gas, then simple direct calculation on the basis of the laws of ideal gases shows that H1/T1 = H2/T2; and as by the conservation of energy the work done is H1 - H2, it follows that the efficiency, measured as the ratio of the work done to the supply of heat, is 1 - T2/T1. If we change the sign of H1 and thus consider heat as positive when it is restored to the system as is H2, the fundamental equation becomes H1/T1 + H2/T2 = 0; and as any complex reversible working system may be considered as compounded in various ways of chains of elementary systems of this type, _whose effects are additive_, the general proposition follows, that in any reversible complete cyclic change which involves the taking in of heat by the system of which the amount is [delta]H, when its temperature ranges between T_r and T_r + [delta]T, the equation [Sigma][delta]H_r/T_r - 0 holds good. Moreover, if the changes are not reversible, the proportion of the heat supply that is utilized for mechanical work will be smaller, so that more heat will be restored to the system, and [Sigma][delta]H_r/T_r or, as it may be expressed, [int]dH/T, must have a larger value, and must thus be positive. The first statement involves further, that for all reversible paths of change of the system from one state C to another state D, the value of [int]dH/T must be the same, because any one of these paths and any other one reversed would form a cycle; whereas for any irreversible path of change between the same states this integral must have a greater value (and so exceed the difference of entropies at the ends of the path). The definite quantity represented by this integral for a reversible path was introduced by Clausius in 1854 (also adumbrated by Kelvin's investigations about the same time), and was named afterwards by him the increase of the _entropy_ of the system in passing from the state C to the state D. This increase, being thus the same for the unlimited number of possible reversible paths involving independent variation of all its finite co-ordinates, along which the system can pass, can depend only on the terminal states. The entropy belonging to a given state is therefore a function of that state alone, irrespective of the manner in which it has been reached; and this is the justification of the assignment to it of a special name, connoting a property of the system depending on its actual condition and not on its previous history. Every reversible change in an isolated system thus maintains the entropy of that system unaltered; no possible spontaneous change can involve decrease of the entropy; while any defect of reversibility, arising from diffusion of matter or motion in the system, necessarily leads to increase of entropy. For a physical or chemical system only those changes are spontaneously possible which would lead to increase of the entropy; if the entropy is already a maximum for the given total energy, and so incapable of further continuous increase under the conditions imposed upon the system, there must be stable equilibrium.

This definite quantity belonging to a material system, its entropy [phi], is thus concomitant with its energy E, which is also a definite function of its actual state by the law of conservation of energy; these, along with its temperature T, and the various co-ordinates expressing its geometrical configuration and its physical and chemical constitution, are the quantities with which the thermodynamics of the system deals. That branch of science develops the consequences involved in just two principles: (i.) that the energy of every isolated system is constant, and (ii.) that its entropy can never diminish; any complication that may be involved arises from complexity in the systems to which these two laws have to be applied.

_The General Thermodynamic Equation._--When any physical or chemical system undergoes an infinitesimal change of state, we have [delta]E = [delta]H + [delta]U, where [delta]H is the energy that has been acquired _as heat_ from sources extraneous to the system during the change, and [delta]U is the energy that has been imparted by reversible agencies such as mechanical or electric work. It is, however, not usually possible to discriminate permanently between heat acquired and work imparted, for (unless for isothermal transformations) neither [delta]H nor [delta]U is the exact differential of a function of the constitution of the system and so independent of its previous history, although their sum [delta]E is such; but we can utilize the fact that [delta]H is equal to T[delta][phi] where [delta][phi] is such, as has just been seen. Thus E and [phi] represent properties of the system which, along with temperature, pressure and other independent data specifying its constitution, must form the variables of an analytical exposition. We have, therefore, to substitute T[delta][phi] for [delta]H; also the _change_ of internal energy is determined by the change of constitution, involving a differential relation of type

[delta]U = -p[delta]v + [delta]W + [mu]1[delta]m1 + [mu]2[delta]m2 + ... + [mu]_n[delta]m_n,

when the system consists of an intimate mixture (solution) of masses m1, m2, ... m_n of given constituents, which differ physically or chemically but may be partially transformable into each other by chemical or physical action during the changes under consideration, the whole being of volume v and under extraneous pressure p, while W is potential energy arising from physical forces such as those of gravity, capillarity, &c. The variables m1, m2, ... m_n may not be all independent; for example, if the system were chloride of ammonium gas existing along with its gaseous products of dissociation, hydrochloric acid and ammonia, only one of the three masses would be independently variable. The sufficient number of these variables (independent components) together with two other variables, which may be v and T, or v and [phi], specifies and determines the state of the system, considered as matter in bulk, at each instant. It is usual to include [delta]W in [mu]1[delta]m1 + ...; in all cases where this is possible the single equation

[delta]E = T[delta][phi] - p[delta]v + [mu]1[delta]m1 + [mu]2[delta]m2 + ... + [mu]_n[delta]m_n (1)

thus expresses the complete variation of the energy-function E arising from change of state; and when the part involving the n constitutive differentials has been expressed in terms of the number of them that are really independent, this equation by itself becomes the unique expression of _all_ the thermodynamic relations of the system. These are in fact the various relations ensuring that the right-hand side is an exact differential, and are of the type of reciprocal relations such as d[mu]_r/d[phi] = dT/dm_r.

The condition that the state of the system be one of stable equilibrium is that [delta][phi], the variation of entropy, be negative for all formally imaginable infinitesimal transformations which make [delta]E vanish; for as [delta][phi] cannot actually be negative for any spontaneous variation, none of these transformations can then occur. From the form of the equation, this condition is the same as that [delta]E - T[delta][phi] must be _positive for all possible_ variations of state of the system as above defined in terms of co-ordinates representing its constitution in bulk, without restriction.

We can change one of the independent variables expressing the state of the system from [phi] to T by subtracting [delta]([phi]T) from both sides of the equation of variation: then

[delta](E - T[phi]) = - [phi][delta]T - p[delta]v + [mu]1[delta]m1 + ... + [mu]_n[delta]m_n.

It follows that for _isothermal_ changes, i.e. those for which [delta]T is maintained null by an environment at constant temperature, the condition of stable equilibrium is that the function E - T[phi] shall be a minimum. If the system is subject to an external pressure p, which as well as the temperature is imposed constant from without and thus incapable of variation through internal changes, the condition of stable equilibrium is similarly that E - T[phi] + pv shall be a minimum.

A chemical system maintained at constant temperature by communication of heat from its environment may thus have several states of stable equilibrium corresponding to different minima of the function here considered, just as there may be several minima of elevation on a landscape, one at the bottom of each depression; in fact, this analogy, when extended to space of n dimensions, exactly fits the case. If the system is sufficiently disturbed, for example, by electric shock, it may pass over (explosively) from a higher to a lower minimum, but never (without compensation from outside) in the opposite direction. The former passage, moreover, is often effected by introducing a new substance into the system; sometimes that substance is recovered unaltered at the end of the process, and then its action is said to be purely _catalytic_; its presence modifies the form of the function E - T[phi] so as to obliterate the ridge between the two equilibrium states in the graphical representation.

There are systems in which the equilibrium states are but very slightly dependent on temperature and pressure within wide limits, outside which reaction takes place. Thus while there are cases in which a state of mobile dissociation exists in the system which changes continuously as a function of these variables, there are others in which change does not sensibly occur at all until a certain _temperature of reaction_ is attained, after which it proceeds very rapidly owing to the heat developed, and the system soon becomes sensibly permanent in a transformed phase by completion of the reaction. In some cases of this latter type the cause of the delay in starting lies possibly in passive resistance to change, of the nature of viscosity or friction, which is competent to convert an unstable mechanical equilibrium into a moderately stable one; but in most such reactions there seems to be no exact equilibrium at any temperature, short of the ultimate state of dissipated energy in which the reaction is completed, although the velocity of reaction is found to diminish exponentially with change of temperature, and thus becomes insignificant at a small interval from the temperature of pronounced activity.

_Free Energy._--The quantity E - T[phi] thus plays the same fundamental

## part in the thermal statics of general chemical systems at uniform

temperature that the potential energy plays in the statics of mechanical systems of unchanging constitution. It is a function of the geometrical co-ordinates, the physical and chemical constitution, and the temperature of the system, which determines the conditions of stable equilibrium _at each temperature_; it is, in fact, the potential energy generalized so as to include temperature, and thus be a single function relating to each temperature but at the same time affording a basis of connexion between the properties of the system at different temperatures. It has been called the _free energy_ of the system by Helmholtz, for it is the part of the energy whose variation is connected with changes in the bodily structure of the system represented by the variables m1, m2, ... m_n, and not with the irregular molecular motions represented by heat, so that it can take part freely in physical transformations. Yet this holds good only subject to the condition that the temperature is not varied; it has been seen above that for the more general variation neither [delta]H nor [delta]U is an exact differential, and no line of separation can be drawn between thermal and mechanical energies.

The study of the evolution of ideas in this, the most abstract branch of modern mathematical physics, is rendered difficult in the manner of most purely philosophical subjects by the variety of terminology, much of it only partially appropriate, that has been employed to express the fundamental principles by different investigators and at different stages of the development. Attentive examination will show, what is indeed hardly surprising, that the principles of the theory of free energy of Gibbs and Helmholtz had been already grasped and exemplified by Lord Kelvin in the very early days of the subject (see the paper "On the Thermoelastic and Thermomagnetic Properties of Matter,