ABSTRACT
Aristotle was the first (and for many centuries the last) voluminous writer on natural history whose aims and methods are guided by what we call the scientific spirit. It is the vulgar notion, that the hyaena possesses in itself both sexes, being a male during one year, and a female the next, and that it becomes pregnant without the co-operation of the male; Aristotle, however, denies this. In some animals, the sexes are distinct, in others they are not so, these are said to beget and be with young by a likeness to other creatures. There is neither male nor female in fixed animals, nor in testacea. It is evident that female fishes have longer lives than males, because females are caught of a greater age than the males; the upper and more forward parts of all animals are larger and stronger, and more firmly built in the male; the hinder and lower parts in the female.
