It cannot be said that any one form of collector is superior all round.
He constructed one form of his coherer of a glass tube a few inches long filled with iron borings or brass filings, having contact plates or pins at the end.
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.
There is probably but little transformation of one form of kinetic energy into another in the plant.
No one form occurs alone, but always grouped together with others in various ways to make up districts, regions and lands of distinctive characters.
