When man has arrived at maturity, his upper part is smaller
than the lower one, but with all other blooded animals the reverse
holds good. By the 'upper' part we mean all extending from the head
down to the parts used for excretion of residuum, and by the 'lower'
part else. With animals that have feet the hind legs are to be rated
as the lower part in our comparison of magnitudes, and with animals
devoid of feet, the tail, and the like.