To return for a moment to some Aristotelian opinions bearing on the generation of life and its transmission of attributes to off-spring. He combated pangenesis, the theory that the semen must come from the whole body, in order to account for the inheritance of so many diverse individual resemblances.49 He was aware that bodily imperfections incidentally acquired would not be inherited, like congenital traits. Yet he realized the constitutional effects arising from the alteration of a small part or organ: that if animals "be subjected to a modification in minute organs, they are liable to immense modifications in their general configuration,"—a phenomenon noticeable with gelded animals.50 Hippocrates had shown how often trouble with one organ worked a general disturbance of the system. Aristotle recognized also that the habits of animals are connected with their main functions of "breeding and the rearing of young, or with procuring a due supply of food; and these habits are modified so as to suit cold and heat and the variations of the season."51He has much to say of migration and hibernation.
In ancient natural science the manner of
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