100 THE CELL IN RELATION TO 



takable parallel between the course of heredity 

 and the history of the chromatin-substanee in the 

 whole cycle of its transformation. In respect to 

 some of the most important phenomena of hered- 

 ity it is only in the chromatin that such a par- 

 allel can be accurately traced. It is this sub- 

 stance, in the form of chromosomes, that shows 

 the association of exactly equivalent maternal 

 and paternal elements in the fertilization of the 

 egg. In it alone do we clearly see the equal dis- 

 tribution of these elements to every part of the 

 body of the offspring. In the perverted forms 

 of development that result from double fertili- 

 zation of the egg and the like it is only in the 

 abnormal distribution of the chromatin-substanee 

 by multipolar division that we see a physical coun- 

 terpart of the derangement of development. 

 Only in the chromatin-substanee, again, do we 

 see in the course of the maturation of the germ- 

 cells a redistribution of elements that shows a 

 parallel to the astonishing disjunction and redis- 

 tribution of the factors of heredity that are dis- 

 played in the Mendelian phenomenon. 



These are perhaps the most striking of a mul- 

 titude of facts that point towards the chromatin 

 as the embodiment of specific primordia of deter- 

 mination. We may be sure that the microscope 

 reveals to us but part of the story ; but that which 

 we see is not for this reason less significant. Ex- 

 periment has taught us, it is true, that the role of 

 the nucleus in determination cannot be regarded 



