472 WM. E. KELLICOTT 



The main objections to the nutrition hypothesis of the causes 

 of embryonic abnormahties and monsters as it has been stated, 

 are, then, the following: it does not afford an interpretation of 

 the results, such as those of Bardeeri and Packard, following 

 treatment of the sperm with radium radiations; it does not 

 afford any suggestions as to the nature of the underlying dis- 

 turbances through which the abnormalities are produced by the 

 unusual conditions used or assumed to be present; it does not 

 explain why the action of the experimental conditions during 

 cleavage should not produce visible results until much later; it 

 does not explain why monsters of the same parentage are di- 

 verse (see Mall '08, p. 12); it does not explain why the effects 

 of treatment are greater when apphed during the earlier stages 

 of development; it does not explain the production of abnor- 

 malities which are not defects or developmental arrests ; it does 

 not avoid the necessity of assuming a degree of differentiation 

 during cleavage and a specificity of the action of the external 

 conditions, both of which have been shown not to exist. 



On the other hand, the hypothesis suggested earlier in this 

 paper, that the causes of abnormal and monstrous development 

 are to be found in the disturbance of the normal organization of 

 the fertilized ovum or cleavage group, as evidenced by the ab- 

 normal characters and distribution of the nuclear and cytoplas- 

 mic substances, avoids these objections and affords an easy 

 interpretation of the observations mentioned. 



It seems to have been premature to have assumed (Mall '08) 

 that all the classes of embryonic abnormalities and monstrosi- 

 ties described by Mall, Bardeen, Spemann, Lewis and Stockard, 

 are really of the same essential nature and due to similar 

 causes. I see no reason for not admitting "that such embryos 

 may result from different causes in different cases, whether they 

 be (1) the abnormal characters of the gametes before fertihza- 

 tion, or disturbances of the early cleavage processes as these 

 concern both nuclear and cytoplasmic constituents, (2) the me- 

 chanical removal of differentiated rudiments, or (3) the lack of 

 energy and materials ordinarily supplied through nutritional 

 pathways, including the pathways within and among the parts 



