200 Pang ens in the Nucleus and Cytoplasm 



of the nucleus, for such functions at least, need not be 

 continuous; if the functions have once been exercised 

 they can continue later without the cooperation of the 

 nucleus.* 



The simplest explanation of this lies obviously in our 

 assumption that nucleus and cytoplasm are both built up 

 from the same pangens, with this difference, only, that 

 in the nucleus every kind of pangen of the given species 

 is represented, while in the remainder of the protoplasm 

 of each cell essentially only those are present which shall 

 attain their power of activity in it. In the nucleus most 

 of them are inactive, that is, they only multiply. Nat- 

 urally there must be also some active pangens in the nu- 

 cleus, as, for example, those that carry out the intricate 

 process of nuclear division ; but this does not affect the 

 main point. In the organs of the protoplast the pangens 

 can continue their multiplication, and, to all appearances, 

 they probably always begin here with a relatively great 

 increase in number. With that they can here remain 

 active or inactive for a shorter or longer period ; or they 

 may be active and inactive by turns. Some become active 

 at their arrival, others later, some independently from 

 external conditions, others again only as a reaction to 

 definite stimuli that start their activity. 



The most remarkable processes that take place in the 

 interior of the nucleus during nuclear division are quite 

 in harmony with the assumption of pangens. Most in- 

 vestigators regard the chromatic thread as the morpho- 



*Godlewski's experiment, in which non-nucleated portions of sea- 

 urchin's eggs were fertilized by the spermatozoa of a crinoid, is now 

 well known. The resulting larvae manifested only maternal charac- 

 ters. In the fifth edition of his "Allgemcine Physiologic," Jena, 1909, 

 Verworn cites this experiment as establishing beyond doubt the fact 

 that hereditary substance is not entirely confined to the nucleus. Tr. 



