WEISMANN'S THEORY OF HEREDITY 69 



ity which he called "Pangenesis," which made 

 out a good case for the admission of the Lam- 

 arckian factor. According to this theory all 

 the somatic or body cells give forth still 

 smaller cells which he calls "gemmules.'' 

 These gemmules are collected, by some pro- 

 cess not explained, in the reproductive organs. 

 Here they are in packets, and these "packets 

 of gemmules" are "the carriers of heredity.'* 

 One can easily see how by this process the 

 effects of use and disuse would be transmiss- 

 ible for an organ shrunk by disuse would not 

 be capably represented by an efficient delega- 

 tion of gemmules at the reproductive head- 

 quarters. 



Speaking of this theory, Grant Allen in his 

 biography of Darwin says, "Let not the love 

 of the biographer deceive us. Not to mince 

 matters, it was his one conspicuous failure, 

 and is now pretty universally admitted as 

 such." It must be remembered however, that 

 Darwin was fully aware of its purely specu- 

 lative character and with his usual caution 

 entitled it the "Provisional Hypothesis of 

 Pangenesis." 



Romanes, one of Weismann's ablest critics, 

 compares Weismann's theory with Darwin's, 

 and while he refuses to defend Pangenesis 

 against Weismann's charge that it is a wholly 



