Habitat.—In the arable fields and along the banks of rivers. Blooms in January and March.
Passifloraceæ.
Passion Flower Family.
Carica Papaya, L.
Nom. Vulg.—Papaya, in many Phil. dialects; Papaya, Papaw, Eng.
Uses.—The decoction of the leaves is used locally in sores and atonic ulcers, followed by a poultice of the boiled and mashed leaves. The natives use the cold infusion of the leaves to wash clothes spotted with blood and the spots disappear rapidly by virtue of the ferment papain which digests the fibrin. The infusion is also very useful as a wash for sores and gangrenous ulcers, modifying their appearance very rapidly.
Before proceeding further it is desirable to give a description of papain, a digestive ferment which exists throughout the whole plant, fruit, trunk, leaves and petioles; it is contained in the milky juice which exudes from all these parts when cut. This juice was studied simultaneously by Wurtz in France and Peckolt in Brazil. The best method of collecting it is to make several superficial, longitudinal incisions in the green fruit without removing it from the tree; immediately an abundance of juice appears in the incisions and coagulates rapidly. The best time to do this is the early morning. The fruit does not suffer by this process but continues developing and ripens perhaps more rapidly, at the same time improving in flavor, becoming sweeter; the seeds, however, atrophy and lose their power of germination. Peckolt gives the following as the composition of the juice:
The milky juice is neutral and coagulates rapidly, separating in two parts: a kind of insoluble pulp and a limpid colorless serum. If combined with fibrin, raw meat, white of egg or gluten it gradually softens them and completely dissolves them in 3 or 4 hours in vitro at 40° C. Combined with milk it coagulates it and soon precipitates the casein which is also dissolved a little later. It digests lumbricoids and tape-worms and the false membrane of croup, in a few hours. According to Wurtz and Bouchut papain is prepared as follows:
The fluid juice or the aqueous solution of the milky exudate is precipitated by the addition of ten times the volume of alcohol. The precipitate, after treating again with concentrated alcohol, is dissolved in water and the addition of sub-acetate of lead eliminates the albuminoids and peptones but does not precipitate the papain. The liquid is filtered and the lead salts separated by means of a current of hydrogen sulphide. It is filtered again and alcohol added gradually, which process first precipitates whatever sulphate of lead may have passed through the filter, and then the papain.