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Indiana University Studies

bases, or equally on both bases; and it seems possible to recognize species of Cynips that have originated by physiologic as well as morphologic mutation. This seems reasonable, for organisms inherit their psychologic and physiologic characters in the same sense as they inherit their morphologic structures. As a matter of fact, the materials transmitted from one generation to the next are neither morphologic nor physiologic characters but an initial bit of simple protoplasm and a physico-chemical organization which will direct the activities of that protoplasm. Many outside, environmental factors also affect the developing organism, but the final form of the plant or animal is inherited in the sense that the inherited genes exert the primary influence on that form. It is in precisely the same sense that the physiologic or psychologic characters of species may be said to be inherited. There seems no sound basis for the oft-made suggestion that physiology is a function of structure—or structure of physiology. It would appear that both are products of the same protoplasm and are controlled by the same hereditary mechanism.