Evidence from Somatic Hist ogene sis 41 



of the more specific attributes. This conception has arisen 

 from a considerable range of observations to the effect that 

 for quite a time in the "early ontogeny of many animals some 

 of the attributes of the embryo can be seen to come directly 

 from the cytoplasm of the egg. Thus both Driesch and 

 Loeb have taken special notice of the fact that, as expressed 

 by Loeb, "when the protoplasm of the egg possesses a strik- 

 ing pigment the larva will possess the same for some time 

 at least" ; and that "if such an egg is hybridized with the 

 sperm of a form whose egg is unpigmented, the larva will, 

 of course, possess a 'maternal' quality which is due solely 

 to the protoplasm (Driesch)". 1 * And in the same connec- 

 tion, Loeb continues : "It is obvious, then, that during the 

 first stages of development an influence of the protoplasm 

 upon heredity may make itself felt, which will disappear as 

 soon as the protoplasm of the egg has been transformed into 

 the tissues of the embryo." One of the cardinal questions we 

 have to consider may be formulated in connection with this 

 last quotation: Have we a right to assume that because 

 an obvious influence of the protoplasm upon heredity dis- 

 appears on the transformation of the protoplasm into tis- 

 sue, therefore all such influence of the protoplasm ceases? 

 To answer this question through observations upon the 

 protoplasm of the cells concerned just before, during, and 

 just after the transformations is exactly the central aim 

 of this section. I can not refrain from making use of 

 another sentence from Loeb to aid in defining the problem 

 more clearly. "It does not seem to me," he writes, "that a 

 discussion as to the relative influence of protoplasm and 

 nucleus upon heredity will prove very fertile, but that it is 

 necessary to transfer this problem as soon as possible from 

 the field of histology to that of chemistry or physical chem- 

 istry." I quite agree that "discussion as to the relative 

 influence of protoplasm and nucleus upon heredity" can not 

 be very fruitful. But the grounds of my skepticism are 



