210 THE PROBLEMS OF EVOLUTION 



of the soma are impressed upon the germinal tis- 

 sues, the converse is equally true and the known 

 interaction of organic structures through the me- 

 dium of hormones is significantly indicative of 

 possible relationships here. I have previously 

 pointed out that continuity is incidental to the 

 reproductive function and that the continuity of 

 the germ plasm is conspicuous only because this is 

 the normal reproductive substance. Continuity of 

 somatic tissues is well known in plants and lower 

 animals, and discontinuity of germ plasm is on 

 record in a sufficient number of cases to destroy 

 effectively the Weismannian hypothesis. 



The most significant facts available in the pres- 

 ent unsatisfactory state of scientific knowledge of 

 evolutionary processes are those brought out in the 

 preceding chapters. The organism exists by virtue 

 of an association between heritage and environ- 

 ment. The cytoplasm exists because of the action 

 of a characteristic chromosome complex upon cyto- 

 plasm derived from the preceding generation under 

 conditions determined by all phases of the com- 

 plex environment. The germinal tissues, even 

 though they are safeguarded to the ultimate ability 

 of the individual organism from external influ- 

 ences, are, nevertheless, produced by the chromo- 

 some complex descended from the original repro- 

 ductive unit under conditions which are dependent 

 upon the life of the individual. And since the 



