part 13

(1876).

[751] _Hist. Plant._ i. 887.

[752] Tom. viii. (1700) tab. 35, sub nom. _Nāi Corana_.

[753] Flückiger, _Documente zur Geschichte der Pharmacie_, Halle, 1876. 84.

The employment of cowhage as a vermifuge originated in the West Indies, and is quite unknown in the East. In England the drug began to attract attention in the latter part of the last century, when it was strongly recommended by Bancroft in his _Natural History of Guiana_ (1769), and by Chamberlaine, a surgeon of London, who published an essay[754] descriptive of its effects which went through many editions. It was introduced into the Edinburgh Pharmacopœia of 1783, and into the London Pharmacopœia of 1809. At the present day it has been almost discarded from European medicine, but has been allowed a place in the _Pharmacopœia of India_ (1868).

The name _Cowhage_ is Hindustani, and in the modern way is written _Kiwânch_, which is generally derived from the Sanskrit _Kapi-Kachchu_, monkey’s itch (Dr. Rice); the corruption into _Cow-itch_ is absurd. _Mucuna_ is the Brazilian name of another species mentioned in 1648 by Marcgraf.[755]

=Description=—The pods are 2 to 4 inches long, about ⁴/₁₀ of an inch wide, and contain 4 to 6 seeds; they are slightly compressed and of a dark blackish brown. Each valve is furnished with a prominent ridge running from the apex nearly to the base, and is densely covered with rigid, pointed, brown hairs, measuring about ⅒ of an inch in length. The hairs are perfectly straight and easily detached from the valves, out of the epidermis of which they rise. If incautiously touched, they enter the skin and occasion an intolerable itching.

=Microscopic Structure=—Under the microscope the hairs are seen to consist of a single, sharply pointed, conical cell, about ¹/₄₀ of an inch in diameter at the base, with uniform brownish walls 5 mkm. thick, which towards the apex are slightly barbed. Occasionally a hair shows one or two transverse walls. Most of the hairs contain only air; others show a little granular matter which acquires a greenish hue on addition of alcoholic solution of perchloride of iron. If moistened with chromic acid, no structural peculiarity is revealed that calls for remark. The walls however are somewhat separated into indistinct layers, the presence of which is confirmed by the refractive power displayed by the hairs in polarized light.

=Chemical Composition=—The hairs when treated with sulphuric acid and iodine assume a dark brown colour. Boiling solution of potash does not considerably swell or alter them. They are completely decolorized by concentrated nitric acid.

=Uses=—Cowhage is administered for the expulsion of intestinal worms, especially _Ascaris lumbricoides_ and _A. vermicularis_, which it effects by reason of its mechanical structure. It is given mixed with syrup or honey in the form of an electuary.

The root and seeds are reputed medicinal by the natives of some part of India. The pods when young and tender may be cooked and eaten.

[754] _On the efficacy of Stizolobium or Cowhage_, Lond. 2nd ed. 1784.

[755] _Hist. Nat. Brasil._ 18.

SEMEN PHYSOSTIGMATIS.

_Faba Calabarica_, _Faba Physostigmatis_; _Calabar Bean_, _Ordeal Bean of Old Calabar_, _Eseré Nut_, _Chop-nut_; F. _Fève de Calabar_; G. _Calabarbohne_.

=Botanical Origin=—_Physostigma venenosum_ Balfour, a perennial plant resembling the common Scarlet Runner (_Phaseolus multiflorus_ Lam.) of our gardens, but having a woody stem often an inch or two thick, climbing to a height of 50 feet or more. It grows near the mouths of the Niger and the Old Calabar River in the Gulf of Guinea.

The imported seeds germinate freely, but the plant, though it thrives vigorously in a hothouse, has not yet, we believe, flowered in Europe. It has already been introduced into India and Brazil. In the latter country Dr. Peckolt, late of Cantagallo, has raised plants which have blossomed abundantly, producing racemes of about 30 flowers each, pendent from the axils of the ternate leaves.

The flower, which is fully an inch across and of a purplish colour, has the form of _Phaseolus_, but is distinguished from that genus by two special characters, namely that it has the style developed beyond the stigma backwards as a broad, flat, hooked appendage,[756] and the seeds half surrounded by a deeply grooved hilum.

=History=—The pagan tribes of Tropical Western Africa compel persons accused of witchcraft to undergo the ordeal of swallowing some vegetable poison. One of the substances employed in this horrid custom is the seed under notice, which is administered in substance or in the form of emulsion, or even as a clyster. It was first made known in England by Dr. W. F. Daniell about the year 1840, and subsequently alluded to in a paper read by him before the Ethnological Society in 1846.[757] The highly poisonous effects of the bean were observed in 1855 by Christison[758] in his own person, and in 1858 by Sharpey, who administered it to frogs.

Before the seed became an object of commerce, it was regarded by the natives with some mystery and was reluctantly parted with to Europeans. It was moreover customary in Old Calabar to destroy the plant whenever found, a few only being reserved to supply seeds for judicial purposes, and of these seeds the store was kept in the custody of the native chief. In 1859, the Rev. W. C. Thomson, a missionary on the West Coast of Africa, forwarded the plant to Professor Balfour of Edinburgh, who figured and described it as a type of a new genus.[759]

[756] The name of the genus, from ϕύσα, a bladder, was formed under the notion that this appendage is _hollow_, which is not the fact.—Mucuna cylindrosperma Welwitsch, from Angola, is probably the same plant. See Holmes, _Pharm. J._ ix. (1879) 913.

[757] Edinb. _New Phil. J._ xl. (1846) 313.

[758] _Edinb. Journ. of Medical Science_, xx. (1855) 193; _Pharm. Journ._ xiv. (1855) 470.

[759] _Trans. Roy. Soc. of Edinb._ xxii. (1861) 305. t. 16-17; see also Baillon, _Hist. des Plantes_, ii. 206. figg. 153-155, and Bentley and Trimen, _Med. Plants_,