Such an enzyme is the pepsin of the stomach of the higher animals.
A third enzyme, the trypsin of the pancreas, possesses the power of both pepsin and erepsin.
It is not quite certain whether a true pepsin exists in plants, but many trypsins have been discovered, and one form of erepsin, at least, is very widespread.
It is much more powerful than carbolic acid in its inhibitory action upon unorganized ferments such as pepsin or ptyalin.
This amyloid substance is slowly and imperfectly digested by pepsin - digestion being more complete with trypsin and by autolytic enzymes.
In a 50% solution or stronger - as when neat whisky is taken - alcohol precipitates the pepsin which is an essential of gastric digestion, E.nd thereby arrests this process.
When the secretion of gastric juice is deficient it may be excited by gastric tonics, such as ten grains of bicarbonate of soda and a drachm of compound tincture of gentian in water shortly before meals, and may be supplemented by the administration of pepsin and hydrochloric acid after meals.
Substances obtained from animals include gland secretions, pepsin and other ferments, musk, cod-liver oil, &c., and to these may be added various antitoxins.
These include such bodies as pepsin, diastase, the pancreatic ferments, papain, the pine-apple ferment, taka-diastase and others, and serve to convert starch into saccharine substances, or albumen into peptone and albumoses.