PROFESSOR WEISMANN'S THEORIES. 489 



competition among the parts for nutriment. This has the effect 

 that active parts are well supplied and grow, while inactive parts 

 are ill supplied and dwindle.* This competition is the cause of 

 " economy of growth " ; this is the cause of decrease from disuse ; 

 and this is the only conceivable cause of that decrease which Dr. 

 Romanes contends follows the cessation of selection. The three 

 things are aspects of the same thing. And now, before leaving 

 this question, let me remark on the strange proposition which has 

 to be defended by those who deny the dwindling of organs from 

 disuse. Their proposition amounts to this : — that for a hundred 

 generations an inactive organ may be partially denuded of blood 

 all through life, and yet in the hundredth generation will be pro- 

 duced of just the same size as in the first ! 



There is one other passage in Dr. Romanes' criticism — that 

 concerning the influence of a previous sire on progeny — which 

 calls for comment. He sets down what he supposes Weismann 

 will say in response to my argument. " First, he may question 

 the fact." Well, after the additional evidence given above, I 

 think he is not likely to do that ; unless, indeed, it be that along 

 with readiness to base conclusions on things " it is easy to im- 

 agine " there goes reluctance to accept testimony which it is diffi- 

 cult to doubt. Second, he is supposed to reply that " the germ- 

 plasm of the first sire has in some way or another become partly 

 commingled with that of the immature ova " ; and Dr. Romanes 

 goes on to describe how there may be millions of spermatozoa and 

 " thousands of millions " of their contained " ids " around the ova- 

 ries, to which these secondary effects are due. But, on the one 

 hand, he does not explain why in such case each subsequent ovum, 

 as it becomes matured, is not fertilized by the sperm-cells pres- 

 ent, or their contained germ-plasm, rendering all subsequent 

 fecundations needless ; and, on the other hand, he does not ex- 

 plain why, if this does not happen, the potency of this remaining 

 germ-plasm is nevertheless such as to affect not only the next 

 succeeding offspring, but all subsequent offspring. The irrecon- 

 cilability of these two implications would, I think, sufficiently 

 dispose of the supposition, even had we not daily multitudinous 

 proofs that the surface of a mammalian ovarium is not a sperma- 

 theca. The third difficulty Dr. Romanes urges is the inconceiva- 

 bility of the process by which the germ -plasm of a preceding male 

 parent affects the constitution of the female and her subsequent 

 offspring. In response, I have to ask why he piles up a mountain 

 of difficulties based on the assumption that Mr. Darwin's expla- 

 nation of heredity by " Pangenesis " is the only available explana- 



* See Social Organism in Westminster Review for January, 1860 ; also Principles of 

 Sociology, § 247. 



tol. xliii. — 34 



