APPENDIX C 207 



and which a more extended acquaintance with the facts usually 

 reveals to be misleading. At the present day, when the trans- 

 mission of acquirements is generally disbelieved, some working 

 hypotheses, as remarkable, but running to the other extreme, 

 have been formulated. Under very high powers of the micro- 

 scope the nuclear matter of the fertilised germ may be seen to 

 divide, apparently with great accuracy. On this slender founda- 

 tion Weismann has built his hypothesis of the continuity of the 

 germ-plasm, adding amazing complications in the way of ids 

 and idants and biophors, hypothetical bearers of heredity. 

 Cheerfully entering into the regions of the unknown and prob- 

 ably unknowable, he has attempted to explain how inborn 

 characters are transmitted. Biologists in larger part have fol- 

 lowed him. 



His speculations, darkening counsel, crop up in every dis- 

 cussion of the subject. As a fact, they have no essential bearing 

 on it. The doctrine, first formulated by Galton, that acquired 

 characters are not transmissible, is one thing, and is supported 

 by abundant evidence. An attempt, on obscure intracellular 

 grounds, to explain how inborn characters are transmissible, 

 even if it involves the corollary that acquired traits are not 

 heritable, is quite another thing. If successful, it would afford 

 additional proof of the former doctrine ; its failure does not 

 involve disproof of it. Galton's theory rests on the plain facts 

 that each individual is derived solely from a single cell, the 

 germ, and that there is no evidence that the somatic cells 

 influence the germs in such a special and unlikely manner as 

 to cause the particular characters the parent acquired to be 

 reproduced by the children. It does not rest on more or less 

 metaphysical speculations concerning the continuity of the germ- 

 plasm, or of ids, idants, or biophors, and so forth. It is deeply 

 to be regretted that this red herring of Weismannism has been 

 drawn across the trail. Weismann may or may not be right. 

 There is not a particle of evidence one way or the other. No 

 one has seen the germ-plasm ; at any rate, no one can recognise 

 it, much less an id or an idant. The whole hypothesis is a 



