908 * INDIAN MEDICINAL PLANTS.
was then added to 55 gallons of milk ; the milk curdled in an hour and a half, affording a firm curd free from taste and smell ; of this a cheese was made which proved to be excellent
(Dymock).
Chemical composition.— The following information is extracted from a re- port upon the " rennet " ferment contained in the seeds, by Mr. Sheridan Lea : —
" Taking equal weights of the seeds, I extracted them for 24 hours with equal volumes of (1) water, (2) 5 per cent, sodic choride, (3) 2 percent, hydro- chloric acid, (4) 3 per cent, sodic carbonate. Equal volumes of each of the above were added in an acid, alkaline, and neutral condition, to equal volumes of milk, and heated in a water-bath at 38° C. The milk was rapidly coagulated by the salt and sodic carbonate extracts, much less rapidly by the other two ; of the four, the salt extract was far the most rapid in its ac- tion. All subsequent experiments have shown that a 5 per cent, solution of sodic chloride is the most efficient in the extraction of the active principle from the seeds.
There is no doubt that the substance which possesses the coagulating power is a ferment closely resembling animal rennet.
I.— A portion of the 5 per cent, sodic chloride extract loses its activity if boiled for a minute or two.
II. — The active principle is soluble in glycerine, and can be extracted from the seeds by this means ; the extract possesses strong coagulating powers even in small amounts.
III.— Alcohol precipitates the ferment body from its solutions ; and the precipitate, after washing with alcohol, maybe dissolved up again without having lost its coagulating powers.
IV.— The active principle of the seeds will cause the coagulation of milk when present in very small quantities, the addition of more of the ferment simply increasing the rapidity of the change.
V.— The coagulation is not due to the formation of acid by the ferment. If some of the active extract be made neutral or alkaline, and added to neutral milk, a normal clot is formed, and the reaction of the clot remains neutral or faintly alkaline.
VI, The clot formed by the action of the ferment is a true clot, resembl- ing in appearance and properties that formed by animal rennet, and it is not a mere precipitate.
The question of preparing an extract which should be capable of being kept for a considerable time is perhaps of importance. Ordinary com- mercial rennet usually contains a large amount of sodic chloride and some alcohol. One specimen I analysed contained 19 per cent, of common salt, and 4 per cent, of alcohol. I have, therefore, added to the 5 per cent, chloride extract mentioned above enough salt to raise the percentage of this to 15 per cent., and also alcohol up to 4 per cent. The activity of the extract is not appreciably altered by this, and such a preparation corresponds very closely in activity with a commercial solution of animal rennet with which I com* pared it. The possibility of making extracts which may be expected to
