Note 440 — ON AIRS, WATERS, AND PLACES.

It is to be borne in mind that Hippocrates, and after him most of the ancient authorities, held that the fœtus is formed from the male semen. This doctrine prevailed generally down to the days of Harvey. Some of the ancient physiologists, however, maintained that “omne animal est ab ovo.” See Plutarch, de Placit. Philos.