No. 605] 



NUCLEUS AND CYTOPLASM 



297 



the double influence which is exerted nu tlif (h'\ flopinu' 

 egg better than any of the others wlio linxc adopted liis 

 "compromise theory." He admits that "most of the dif- 

 ferentiations of the cytoplasm have arisen during the 

 ovarian history of the egg and as a result of the inter- 

 action of nucleus and cytoplasm." He has demonstrated 

 better than any other one man how com]dox and definite 

 these diflferentiations in the egg (•\toi)la>ni arc. All will 

 agree with him when he say> that they ■ ' foi-c^hadow" the 

 future organism. But "cyto])lasmic organization, while 

 affording the immediate conditions of development, is 

 itself a result of the nature of the nuclear substance which 

 represents by its inherent composition the totality of 

 heritable potence." These last are the words of E. B. 

 Wilson (1895, p. 25), although he has translated and 

 adapted them from an earlier paper by Driesch. They 

 represent the opinion of "Wilson and of Driesch in full 

 accord. "The nuclear substance" referred to was even 

 then known to contain e(iuality of maternal and paternal 

 chromatin. 



AVilson himself had been able to demonstrate that the 

 structure of the cytoplasm in sea-urchin eggs w;is ac- 

 quired during ovarian life, and on the basis of tliis and of 

 a consideral)le ])ody of similar evidence lie was able to 

 (•()iiclii(l(^ finite dcHnitcly : 



The only link which is needed to make tlie chain com- 

 plete is some substantial body of evidence, demonstrating 

 the effect and the mechanism of action of the iiuelens on 

 the cytoplasm. This, it must be admitted. iia> not i)een 

 entirely filled. Niigeli, to be sure, held a theory of a 

 dynamie effect of tlie nuclear idioplaM.i on tlie r>topla^m, 



