Cashew Nut, the fruit of the aimcardium occidentale cultivated in the West Indies and other tropical countries. The tree, which resembles-the walnut tree, is large, with oval, blunt, alternate leaves; the flower is rose-colored and fragrant; the stem furnishes a milky juice, which when dry becomes black and is used as a varnish. The tree also secretes a gum having the qualities of gum arabic, and known in commerce as codjii gum. In South America, from whence it is imported, bookbinders use it as a varnish for their books to protect them from moths and ants. The fruit is a pear-shaped receptacle, having an agreeable acid flavor with some astringency, and at the end the kidney-shaped ash-colored nut. This has a shell of three layers, the outer and inner hard and dry, while the intermediate contains a quantity of black, acrid, caustic oil, strong enough to excoriate the lips of those who crack the nut with their teeth; and in India it is sometimes applied to the floors to drive away ants. To destroy this acrid matter, the nuts are roasted, which renders them when eaten wholesome and agreeable.
The roasting is carefully conducted, as the acridity of the fumes is sufficient to produce severe inflammation in the face and hands of the roaster.