Note B — Chapter III · CONSUMPTION—(Continued).

Ptyalin, a vegetable matter contained in healthy saliva, has very peculiar properties: “if mixed with starch and kept at a moderate warm temperature, it turns that starch into grape-sugar. The importance of this operation becomes apparent when one reflects that starch is insoluble, and therefore, as such, useless as nutriment, while the sugar formed from it is highly soluble, and readily oxidizable.”—Huxley.