198 Pang ens in the Nucleus and Cytoplasm 



tein, glucose, and salts, present only in the water of im- 

 bibition, as secondary to them. How these particles are 

 constituted, whether they themselves contain water of 

 imbibition, or not, and how the visible characters are 

 conditioned by their structure, we do not know; much 

 less are we acquainted with their manner of dividing and 

 multiplying. Apart from these difficulties, which adhere 

 to any theory, the assumption that these particles are 

 identical with the bearers of the hereditary traits, is ob- 

 viously the simplest one that can be made with regard 

 to the structure of living matter. 



From this point of view, the origination of the nucleus 

 in the phylogenetic differentiation of the lowest organ- 

 isms, appears to us as an extremely practical division of 

 labor. Hitherto, the active and the inactive pangens were 

 lying everywhere in the protoplasm, side by side and 

 intermingled. And the higher the differentiation that had 

 been reached, the greater would be the number of diverse 

 pangens, in the same protoplast; and the greater, also, 

 would have to be the number of the latent among the 

 active ones. The latter would thereby be distributed over 

 a relatively large space, and the efficiency of the whole 

 must therefore suffer. By the formation of the nucleus 

 this situation could be changed. In the latter the inactive 

 pangens would be accumulated and stored; the active 

 ones could come nearer each other. - 



Let us further elaborate the picture. As soon as the 

 moment arrived for certain pangens, which until then 

 had been inactive, to be set into activity, they would ob- 

 viously pass from the nucleus into the cytoplasm. But 

 in so doing they would retain their characters, and es- 

 pecially their power to grow and multiply. Only a few 

 like pangens would therefore have to leave the nucleus 



