ABSTRACT
The process by which grape and other saccharine vegetable juices are converted after much frothing, turbidity, and ultimate clarification, into an intoxicating drink is as old as the history of mankind. The bitter and the sweet almond both contain an enzyme, or rather a pair of enzymes commonly known under the collective term emulsin, which together break up the amygdalin in the manner shown in the equation. Pepsin acts best in an acid medium such as the gastric juice which contains 0·2 per cent of hydrochloric acid. Trypsin works best in an alkaline solution such as the pancreatic juice, which also contains several other enzymes. A different class is represented by rennet, which is prepared from the lining of the stomach of the calf and is used for curdling milk in the manufacture of cheese. The clotting of blood is brought about by a similar agent originating under certain conditions in blood itself and called thrombin.
