Evidence from Somatic Histogenesis 49 



as the examination of Conklin's work has shown. But if on 

 the basis of such observation it can be asserted that attri- 

 butes of egg and early embryo are determined by the cyto- 

 plasm, how escape asserting that the same sort of evidence 

 touching the production of the adult attributes, those per- 

 taining to spinule cells, are likewise determined by the cyto- 

 plasm? 



It was remarked above that if all known relevant facts 

 were taken into account and consistency in terminology be 

 maintained, Conklin's statement to the effect that we are 

 vertebrates because our mothers were vertebrates and pro- 

 duced eggs of the vertebrate type, but that our species and 

 racial characters, color of skin and hair, and so forth, are 

 determined by the chromatin of both parental germ-cells, 

 would have to be greatly modified. We are now in position 

 to see what modification is necessary. Although the state- 

 ment is undoubtedly true that we are vertebrates because 

 we develop from vertebrate eggs, the implication that the 

 attributes which identify us with the human species and the 

 Caucasian race are explained, so far as heredity is con- 

 cerned, by the chromatin of the germ-cells, whether male or 

 female or both, is not in accordance with all the observed 

 facts bearing on the problem. The same kind of evidence 

 on which the assertion is based that the embryonic charac- 

 ters are determined by the egg cytoplasm, requires the 

 assertion that skin and other adult characters are deter- 

 mined by the same means. 



This leads to the remarks we have to make about con- 

 sistency in the use of terms. The critical reader will hardly 

 have failed to notice the difference in application of the 

 word "determined" as used by Conklin in the quotation 

 we are examining. When it is said that the color of skin, 

 hair, stature and so on are determined by the germ-cells, 

 the determining act or condition is far removed from that 

 which is determined, and no direct causal connection be- 



