468 WM. E. KELLICOTT 



Stockard ('13 b) explains ''the fact that a number of eg||s 

 when subjected to the same solution do not all respond in a hke 

 manner" merely by regarding this as "a typical case of differ- 

 ences in individual resistance and vigor which is observed among 

 any one hundred individuals of any living species" (p. 282). 

 But the kinds of differences found here are not at all such that 

 they may be regarded as illustrations of that normal fluctuation 

 in all characteristics which represents the reactions of organisms 

 to the incidence of environing conditions. It is probably true 

 that eggs and embryos do differ in those complex conditions 

 which we summarize in the words 'resistance and vigor.' But 

 these qualities do not determine whether an embryo shall or shall 

 not have eyes, hearts, pigment cells, and so forth. We are 

 dealing with a wholly and fundamentally different phenomenon. 



An important objection to this nutrition hypothesis, it seems 

 to me, is that there is little or no actual evidence given that the 

 nutritional conditions of the egg or embryo are directly affected. 

 The evidence offered is that defective and monstrous embryos 

 result from various methods of chemical treatment; but it is 

 these defective and monstrous embryos that are to be explained. 

 In the few instances where there is evidence of abnormal rela- 

 tions between embryonic and vitelUne portions of the egg, it is 

 more reasonable, in view of the great variety of other conditions 

 found, to regard this too as a result of a primary disturbance, 

 rather than as the cause of a variety of conditions which may 

 also occur in its absence. 



The suggestion as to the responsibility of abnormal nutri- 

 tional relations as the cause of abnormal and monstrous develop- 

 ment was made primarily in connection with the human embryo 

 and then extended to other forms. It is quite possible that in 

 the human and other placental mammalian embryos such effects 

 may in some cases be found to be specific and to be related to 

 nutritional abnormahties due to disturbances in the parental 

 organism. However, the mammalian embryo develops for some 

 hours or days before implantation occurs and becomes effective 

 as a nutritional factor so that it is only subsequently to 

 that time that the effects of faulty nutrition might be exercised. 



