Kasuy

Uses

The pericarp of the nut contains an essential oil which is very irritant and used by the Hindoos as a vesicant; it severely blisters the lips and tongues of imprudent persons who break the nut without taking the precaution of cleansing it of the oil before opening it. In addition to the oil called cardol, the pericarp contains an especial acid anacardic, a little tannin and ammonia. Cardol (C21H31O2) is an oleaginous, yellow liquid very unstable, neutral, soluble in alcohol and ether, insoluble in water, volatile, and vesicant if applied to the skin. “Anacardic” acid is white, crystalline, odorless, with a burning, aromatic taste. It melts at 26° and decomposes at 200° forming a colorless oil; it is not vesicant, burns with a dark flame, and has the odor of rancid oil. A tincture of the pericarp has been made (1 part to 10 of alcohol) and given internally as a vermifuge in doses of 2–10 drops. Cardol, according to some authors, does not exercise a vesicant action in the gastro-intestinal canal, because it is not dissolved by the gastro-intestinal juices; I am sure, however, that I have seen a choleraic diarrhœa brought on by swallowing, in fun, the pericarp of one nut and a half. Cardol is eliminated by the urine.

The kernel is edible and has a very agreeable taste when roasted. By expression it yields a sweet, yellowish oil, density 0.916.

The trunk exudes a gum resin in masses varying in color from red to yellow.

The fleshy part, called the fruit, is edible but contains a certain quantity of cardol not only evidenced by the odor but by the smarting of the mouth and throat after eating. It is very juicy and the expressed liquid is fermented in Bombay and distilled to make a very weak alcohol which sells for the very low price of 4 annas (5 cents gold) a gallon. This alcohol is again distilled and a stronger obtained which sells for 1½ rupees a gallon. The Portuguese of India make a sort of wine from the fermented juice of the fruit, which, like the weak alcohol we have mentioned, is a well-known diuretic and is used as a liniment.

The gum resin of the trunk contains 90% of anacardic acid and 10% cardol. Wood soaked in it is preserved from the ravages of insects, especially of white ants, for which purpose it is used by bookbinders also. Therapeutically it is used externally in leprosy, old ulcers and to destroy corns, but on account of its rubefacient and vesicant qualities it is necessary to use it cautiously.

Botanical description

A tree, 18° high, with leaves cuneiform, glabrous, stiff, short-petioled. Flowers polygamous in terminal panicles. Calyx with 5 erect segments, imbricated, caducous. Corolla, 5 linear, lanceolate petals, curved and imbricated. Stamens 8–10, all fertile. Filaments united to one another and to the disc. Ovary heart-shaped. Style filiform and eccentric. Stigma defective. Ovule solitary. Fruit a reniform nut enclosed in a pulpy pyriform body, formed by the matured disc and extremity of the peduncle. Seed reniform, testa membranous.