Humans as Self-Domesticating Animals

at the end of the Pleistocene, certain human groups and their animal associates began progressively to show parallel reductions in size and stature, cranial gracilization, changes in post-cranial robusticity, shortening of the face and jaws, tooth crowding and malocclusion, and tooth-size reduction and simplification. There has been no recent attempt to explain the parallelism, although numerous explanations exist for the changes as they affect one or other of the parties. Some of the explana...

 Outline of the Natural Sciences Pt. II

The circulation of the blood was long since known; but the disposition of the vessels which conveyed the chyle to mix with it, and repair its losses; the existence of a gastric fluid which disposes the elements to the decomposition necessary to separate from organised matter, that portion which is proper to become assimilated with the living fluids; the changes undergone by the various parts and organs in the interval between conception and birth, and afterwards during the different ages of l...