Hidden atomic particles?

Usage examples of secretions.

Now, it is a remarkable fact, which affords additional and important evidence, that the ferment of Drosera is closely similar to or identical with pepsin, that none of these same substances are, as far as it is known, digested by the gastric juice of animals, though some of them are acted on by the other secretions of the alimentary canal.

Nor does chlorophyll seem affected by the intestinal secretions of various animals, judging by the colour of their excrement.