134 An Examination of Weismannism. 



Such being the fundamental points of difference 

 between these three theories of heredity, we have now 

 to consider more particularly those which obtain 

 between Galton's and Weismann's. 



The general doctrine of gem mules (i. e. somatic- 

 cell-germs) is accepted by Galton ; but instead of 

 supposing, as Darwin supposed, that these minute 

 bodies freely circulate through all the body tissues, 

 so that some of them are absorbed from all the 

 somatic-cells by the germ-cells, and there constitute 

 the entire mass of hereditary material out of which 

 the offspring will afterwards be formed, Galton sup- 

 poses that gemmules circulate with comparative diffi- 

 cult}*, and that only comparatively few of them gain 

 access to the germ-cells in each generation. Hence, 

 characters acquired in the individual lifetime are 

 much less heritable than those which are called con- 

 genital. For congenital characters are due to the 

 " continuity " of stirp through numberless genera- 

 tions in the phylogeny of the organism ; hence such 

 characters are represented by a vastly greater number 

 of equivalent hereditary elements. Weismann. on the 

 other hand, rejects the doctrine of gemmules in toto. 



Again, according to Galton's view, " individual 



however, appears to me radically unsound. For instance, he says, " The 

 hereditary continuation in each part is pre-determined in each part 

 from the germ onwards. The right and left ears could not possibly 

 resemble each other, if the relative strength of the hereditary tendencies 

 on both sides were not pre-determined for all parts of the child by the 

 nature of the paternal and maternal idants." Very well. But. if so, the 

 theory of determinants is just as much pre-formative as is that of 

 gemmules. Or, conversely, the latter is quite as epigenetic as the former. 

 Both are alike determinative, while neither supposes that the determina- 

 tion is due to a pre-formed miniature of the future child in the fertilized 

 egg of its mother ; but to a particulate representation in the latter of 

 every heritable part of the former. 



