part 23

(1877).

[2331] We accept the opinion of Körnicke (_Monographiæ Marantaccarum Prodromus, Bull. de la Soc. imp. des Naturalistes de Moscou_, xxxv. 1862, i.) that _Maranta arundinacea_ L. and _M. indica_ Tuss. are one and the same species. Grisebach maintains them as distinct (_Flora of the British West Indian Islands_, 1864, 605), allowing both to be natives of Tropical America; but he fails to point out any important character by which they may be distinguished from each other. According to Miquel (_Linnæa_, xviii. 1844. 71) the plant in the herbarium of Linnæus labelled _M. arundinacea_, is _M. indica_. We have ourselves made arrowroot from the fresh rhizomes of _M. arundinacea_, in order to compare it with an authentic specimen obtained in Java from _M. indica_: no difference could be found between them.

[2332] Sloane, _Catal. plant. quæ in ins. Jamaica sponte proveniunt, vel vulgò coluntur_, Lond. 1696. 122; also _Hist. of Jamaica_, i. (1707) 253.

Patrick Browne (1756) notices the reputed alexipharmic virtues of _Maranta_, which was then cultivated in many gardens in Jamaica, and says that the root “_washed, pounded fine and bleached, makes a fine flour and starch_”—sometimes used as food when provisions are scarce.[2333]

Hughes, when writing of Barbadoes in 1750, describes arrowroot as a very useful plant, the juice mixed with water and drunk being regarded as “_a preservative against any poison of an hot nature_”; while from the root the finest starch is made, far excelling that of wheat.[2334] The properties of _Maranta arundinacea_ as a counter-poison are insisted upon at some length by Lunan,[2335] who concludes his notice of the plant by detailing the process for extracting starch from the rhizome.

Arrowroot came into use in England about the commencement of the present century, the supplies being obtained, as it would appear, from Jamaica.[2336]

The statements of Sloane, which are confirmed by Browne and Lunan, plainly indicate the origin and meaning of the word _arrowroot_, and disprove the notion of the learned C. F. Ph. von Martius (1867) that the name is derived from that of the Arnac or Aroaquis Indians of South America, who call the finest sort of fecula they obtain from the Mandioc _Aru-aru_. It is true that _Maranta arundinacea_ is known at the present day in Brazil as _Araruta_, but the name is certainly a corruption of the English word _arrowroot_, the plant according to general report having been introduced.[2337]

=Manufacture=—For the production of arrowroot, the rhizomes are dug up after the plant has attained its complete maturity, which in Georgia is at the beginning of winter. The scales which cover them are removed and the rhizomes washed; the latter are then ground in a mill, and the pulp is washed on sieves, or in washing machines constructed for the purpose, in order to remove from it the starch. This is allowed to settle down in pure water, is then drained and finally dried with a gentle heat. Instead of being crushed in a mill, the rhizomes are sometimes grated to a pulp by a rasping machine.

In all stages of the process for making arrowroot, nice precautions have to be taken to avoid contamination with dust, iron mould, insects, or anything which can impart colour or taste to the product. The rhizome contains about 68 per cent. of water, and yields about a fifth of its weight of starch.[2338]

[2333] _Civil and Natural History of Jamaica_, 1756. 112. 113.

[2334] _Natural History of Barbados_, 1750. 221.

[2335] _Hortus Jamaicensis_, i. (1814) 30.

[2336] Thus in 1799 there were exported from Jamaica 24 casks and boxes of “_Indian Arrowroot_.”—Renny, _Hist. of Jamaica_, 235.

[2337] Since the above was written, the following lines bearing on this question have been received from Mr. Spruce:—“ ... I know not Martius’ derivation of ‘_arrowroot_.’ On the Amazon it is called ‘_ararúta_’—plainly a corruption of the English name, and explained by the fact that it was first cultivated, as I was told, from tubers obtained in the East Indies.”

[2338] This was in the German colony of Blumenau in Southern Brazil—Eberhard, _Arch. der Pharm._ 134 (1868) 257.

=Description=—Arrowroot is a brilliant white, insipid, inodorous, powder, more or less aggregated into lumps which seldom exceed a pea in size; when pressed it emits a slight crackling sound. It exhibits the general properties of starch, consisting entirely of granules which are subspherical, or broadly and irregularly egg-shaped; when seen in water they show a distinct stratification in the form of fine concentric rings around a small star-like hilum. They have a diameter of 5 to 7 mkm. when observed in the air or under benzol. If the water in which they lie be cautiously heated on the object-stage of the microscope, the tumefaction of the granules will be found to begin exactly at 70° C. Heated to 100° C. with 20 parts of distilled water, arrowroot yields a semi-transparent jelly of somewhat earthy taste and smell. By hydrochloric acid of sp. gr. 1·06, arrowroot is but imperfectly dissolved at 40° C.

The specific gravity of all varieties of starch is affected by the water which they retain at the ordinary temperature of the air. Arrowroot after prolonged exposure to an atmosphere of average moisture, and then kept at 100° C. till its weight was constant, was found to have lost 13·3 per cent. of water. On subsequent exposure to the air, it regained its former proportion of water.

Weighed in any liquid which is entirely devoid of action on starch, as petroleum or benzol, the sp. gr. of arrowroot was found by one of us to be 1·504; but 1·565 when the powder had been previously dried at 100° C.

=Microscopic Structure of Arrowroot and of Starch in general=—The granules are built up of layers,—a structure which may be rendered evident by the gradual action of chloride of calcium, chromic acid, or an ammoniacal solution of cupric oxide. When one of these liquids in a proper state of dilution is made to act upon starch, or when for that purpose a liquid is chosen which does not act upon it energetically, such as diastase, bile, pepsin, or saliva, it is easy to obtain a residue, which according to Nägeli, is no longer capable of swelling up in boiling water, nor is immediately turned blue by iodine, except on the addition of sulphuric acid; but which is dissolved by ammoniacal cupric oxide. These are the essential properties of cellulose; and this residue has been regarded as such by Nägeli, while the dissolved portion has been distinguished as _Granulose_ (Maschke, 1852).

C. Nägeli in his important monograph on starch[2339] has described the

## action of saliva when digested with starch for a day, at a temperature

of 40° to 47° C.; he says that the residue is a skeleton, corresponding in form to the original grain but somewhat smaller, light, and very mobile in water. He concludes that its interstitial spaces must have been previously filled with granulose.

This experiment, which has been repeated by one of us (F.), does not in our opinion warrant all the inferences that Nägeli has drawn from it: it is true that many separate parts of the grain are dissolved by the saliva, while others have disappeared down to a mere film, and others again have been attacked in a very irregular manner. But we cannot agree with the statement that anything comparable to a skeleton of the grain has been left. After longer action at a higher temperature, which however must not exceed 65° C., a more copious dissolution of the starch, either by saliva or by bile, takes place; but in no case is it complete.[2340]

[2339] _Die Stärkekörner_, Zürich, 1858. 4°, also W. Nägeli, _Stärkegruppe_, etc., Leipzig, 1874.

[2340] Further particulars on this question may be found in my paper _Ueber Stärke und Cellulose—Archiv der Pharmacie_, 196 (1871) 7.—F. A. F.

=Chemistry of Starch=—Its composition answers to the formula (C₆H₁₀O₅)₂+3 OH₂, or when dried at 100° C., C₆H₁₀O₅. Musculus however showed, in 1861, that by the action of dilute acids or of _Diastase_, starch is resolved into _Dextrin_, C₁₂H₂₀O₁₀, and _Dextrose_, C₆H₁₂O₆, with which decomposition, the formula, C₁₈H₃₀O₁₅, would be more in accord. Sachsse (1877) on the other hand advocates the formula C₃₀H₆₂O₃₁ + 12 OH₂.

Cold water is not without action on starch; if the latter be continuously triturated with it, the filtrate, in which no particles can be detected by the microscope, will assume a blue colour on addition of iodine, without the formation of a precipitate. The proportion of starch thus brought into solution is infinitely small, and always at the expense of the integrity of the grains. It is even probable that the solution in this case is due to the minute amount of heat, which must of necessity be developed by the trituration.

Certain reagents capable of attacking starch act upon it in very different ways. The action in the cold of concentrated aqueous solutions of easily soluble neutral salts or of chloral hydrate is remarkable. Potassium bromide or iodide, or calcium chloride for instance, cause the grains to swell, and render them soluble in cold water. At a certain degree of dilution a perfectly clear liquid is formed, which at first contains neither dextrin nor sugar; it is coloured blue, but is not precipitated by iodine water; and starch can be thrown down from it by alcohol. This precipitate, though entirely devoid of the structural peculiarity of starch, still exhibits some of the leading properties of that substance; it is coloured in the same manner by iodine, does not dissolve even when fresh in ammoniacal cupric oxide, and after drying is insoluble in water, whether cold or boiling. The progress of the solvent is most easily traced when calcium chloride is used, as this salt acts more slowly than the others we have mentioned. It leaves scarcely any perceptible residue. This fact in our opinion militates against the notion that starch is composed of a peculiar amylaceous substance, deposited within a skeleton of cellulose.

The remarkable action of iodine upon starch was discovered in 1814 by Colin and Gaultier de Claubry. It is extremely different in degree, according to the peculiar kind of starch, the proportion of iodine, and the nature of the substance the grains are impregnated with, before or after their treatment with iodine. The action is even entirely arrested (no blue colour being produced) by the presence in certain proportion of quinine, tannin, _Aqua Picis_, and of other bodies.

The combination of iodine with starch does not take place in equivalent proportions, and is moreover easily overcome by heat. The iodine combined with starch amounts at the utmost to 7·5 per cent. The compound is most readily formed in the presence of water, and then produces a deep indigo-blue. Almost all other substances capable of penetrating starch grains, weaken the colour of the iodine compound to violet, reddish yellow, yellow, or greenish blue. These different shades, the production of which has been described by Nägeli with great diffuseness, are merely the colours which belong to iodine itself in the solid, liquid, or gaseous form. They must be referred to the fact that the particles of iodine diffuse themselves in a peculiar but hitherto unexplained manner within the grain or in the swollen and dissolved starch.

=Commerce of Arrowroot=—The chief kinds of arrowroot found in commerce are known as _Bermuda_, _St. Vincent_, and _Natal_; but that of Jamaica and other West India Islands, of Brazil, Sierra Leone, and the East Indies, are quoted in price-currents, at least occasionally. Of these the Bermuda enjoys the highest reputation and commands by far the highest price; but its good quality is shared by the arrowroot of other localities, from which, when equally pure, it can in nowise be distinguished. Greenish,[2341] however, points out that in Natal arrowroot the layers (or laminæ) are more obvious than in other varieties, although it appears that the former is also produced by Maranta.

The importations of arrowroot into the United Kingdom during the year 1870 amounted to 21,770 cwt., value £33,063. Of this quantity the island of St. Vincent in the West Indies furnished nearly 17,000 cwt., and the colony of Natal about 3000 cwt. The exports from St. Vincent in 1874 were 2,608,100 lb, those of the Bermudas in 1876 only 45,520 lb.[2342] The shipments from the colony of Natal during the years 1866 to 1876 varied from 1,076 cwt. in 1873 to 4,305 cwt. in 1867.[2343]

[2341] _Yearbook of Pharm._ (1875) 529.

[2342] Papers relating to H.M. Colonial Possessions. Reports for 1875-76. Presented to both Houses of Parliament, July 1877. 54. 4.

[2343] Statist. Abstr. for the several Colonial and other Possessions of the United Kingdom, 14th number, 1878. p. 60.

=Uses=—Arrowroot boiled with water or milk is a much-valued food in the sick-room. It is also an agreeable article of diet in the form of pudding or blancmange.

=Adulteration=—Other starches than that of _Maranta_ are occasionally sold under the name of _Arrowroot_. Their recognition is only possible by the aid of the microscope.

Substitutes for Arrowroot.

_Potato Starch_—This substance, known in trade as _Farina_ or _Potato Flour_, is made from the tubers of the potato (_Solanum tuberosum_ L.) by a process analogous to that followed in the preparation of arrowroot. It has the following characters:—examined under the microscope, the granules are seen to be chiefly of two sorts, the first small and spherical, the second of much larger size, often 100 mkm. in length, having an irregularly circular, oval or egg-shaped outline, finely marked with concentric rings round a minute inconspicuous hilum. When heated in water, the grains swell considerably even at 60° C. Hydrochloric acid, sp. gr. 1·06, dissolves them at 40° quickly and almost completely, the granules being no longer deposited, as in the case of arrowroot similarly treated. The mixture of arrowroot and hydrochloric acid is inodorous, but that of potato starch has a peculiar though not powerful odour.

_Canna Starch, Tous-les-Mois_,[2344] _Toulema, Tolomane_—A species of _Canna_ is cultivated in the West India Islands, especially St. Kitts, for the sake of a peculiar starch which, since about the year 1836, has been extracted from its rhizomes by a process similar to that adopted in making arrowroot. The specific name of the plant is still undetermined; it is said to agree with _Canna edulis_ Ker (_C. indica_ Ruiz et Pavon).[2345]

[2344] It is commonly stated that the name _Tous-les-mois_ was given in consequence of the plant flowering _all the year round_. But this explanation appears improbable: no such name is mentioned by Rochefort, Aublet, or Descourtilz, who all describe the _Balisier_ or _Canna_. It seems more likely that the term is the result of an attempt to confer a meaning on an ancient name—perhaps _Touloula_, which is one of the Carib designations for _Canna_ and _Calathea_.

[2345] Fig. in Bentley and Trimen’s _Medic. Plants_,