NATIONAL, ACADEMY BIOGRAPHICAL, MEMOIRS- — VOL,. VII 



feven the special researches, some of which have been named 

 above, were permeated by philosophical inquiry, and most of 

 his books and later contributions were devoted to the deeper 

 philosophical meanings of vital phenomena. 



As a boy he had read the works of Darwin, and had been 

 immensely impressed by them, and to the last he yielded to no 

 one in his admiration and reverence for that great master. 

 Probably no other disciple of Darwin was more thoroughly 

 acquainted with his works, and very frequently when criticisms 

 of Darwinism appeared he would point out the fact that the 

 critic did not understand what Darwinism is, or that Darwin 

 had already met and answered the objection raised. 



One of his earliest papers, entitled "A provisional hypothesis 

 of pangenesis," which he read before the American Association 

 for the Advancement of Science in 1876, contained the germ 

 of many of his later theories and speculations. This germ is 

 the hypothesis that, whereas fully established peculiarities are 

 transmitted by asexual reproduction as well as by the ovum, 

 new characteristics are transmitted only through gemmules, 

 which are stored in the reproductive glands of the male, and 

 are transmitted to the egg in fertilization. Gemmules from the 

 body of the female may pass into the ova, but there is here no 

 organ for the aggregation and transmission of them. "The 

 male element is thus the originating, the female the perpetu- 

 ating factor in the reproductive process. The female is con- 

 servative, the male progressive." 



This speculation, which he sought to support by many obser- 

 vations, became the basis of a volume of 336 pages, entitled 

 "The law of heredity," which he published in 1883. This vol- 

 ume, however, contained much of value besides the speculation 

 named. In some respects it anticipated the Germ-plasm theory 

 of Weismann and the Mutation theory of De Vries, and it won 

 the highest commendation from Huxley and other leaders in 

 biology. Like many other profound thinkers on the subject of 

 heredity, he recognized that no hypothesis of epigenesis offers 

 a satisfactory explanation of heredity, and that there is no 

 escape from some form of the evolution hypothesis. The form 

 which he adopts is Darwin's hypothesis of pangenesis, with 

 the modification suggested above. He points out that it is not 



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