HISTORY OF THE FERTILIZATION PROBLEM 19 



female chromosome, and that in the formation of the 

 polar globules each throws out the male chromatin which 

 it contains. " 



Van Beneden by a veritable stroke of genius thus 

 anticipates the entire chromosome doctrine of the present 

 time, even though certain aspects of his interpretation 

 were not entirely fortunate. 



With the establishment of the nuclear theory, des- 

 tined soon to be elevated into the doctrine of chromosome 

 individuality, a certain duality of cell life was recognized 

 in which nucleus and cytoplasm, however interdependent, 

 were regarded as playing specific roles. But there 

 was no logical reason for stopping at duality, and the 

 centrosome soon came to be recognized under Van 

 Beneden' s and Boveri's leadership as a third organ of 

 cell lif e reproducing itself by division. The development 

 of this idea was due, not only to studies of karyokinesis, 

 but also to the series of fertilization studies which began 

 with Boveri's classic papers on Ascaris (1887-88). In 

 these papers Boveri is convinced of the necessity of 

 making "the sharpest distinction between fertilization 

 and heredity, i.e., between the question how egg and 

 spermatozoon produce a cell capable of division, and the 

 question how these cells come to be capable of reprodu- 

 cing the qualities of the parents in the offspring"; this 

 distinction has since been generally recognized. Boveri's 

 solution of the fertilization problem was in terms of the 

 centrosome hypothesis: the egg is devoid of the organ 

 of cell division, the centrosome; capacity for division, 

 hence the initiation of the developmental processes, 

 is restored through the introduction of a centrosome into 

 the egg by the spermatozoon. 



