650 APPENDIX B. 



due. But, on the one hand, he does not explain why in such 

 cases each subsequent ovum, as it becomes matured, is not fer- 

 tilized by the sperm-cells present, or their contained germ-plasm, 

 rendering all subsequent fecundations needless ; and, on the other 

 hand, he does not explain 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 irreconcilability 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 spermatheca. The third reply Dr. Romanes urges, is the 

 inconceivability of the process by which the germ-plasm of a pre- 

 ceding 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 explanation of heredity by " Pangenesis " is the only 

 available explanation preceding that of Wcismann ? and why 

 he presents these difficulties to me, more especially ; deliberately 

 ignoring my own hypothesis of physiological units ? It cannot 

 be that he is ignorant of this hypothesis, since the work in which 

 it is variously set forth (Principles of Biology, 66 97) is one 

 with which he is well acquainted : witness his Scientific Evidences 

 of Organic Evolution ; and he has had recent reminders of it in 

 Weismann's Germ-plasm, where it is repeatedly referred to. Why, 

 then, does he assume that I abandon my own hypothesis and 

 adopt that of Darwin ; thereby entangling myself in difficulties 

 which my own hypothesis avoids ? If, as I have argued, the 

 germ-plasm consists of substantially similar units (having only 

 those minute differences expressive of individual and ancestral 

 differences of structure), none of the complicated requirements 

 which Dr. Romanes emphasizes exist ; and the alleged incon- 

 ceivability disappears. 



Here I must end : not intending to say more, unless for some 

 very urgent reason ; and leaving others to carry on the discus- 

 sion. I have, indeed, been led to suspend for a short time my 

 proper work, only by consciousness of the transcendent import- 

 ance of the question at issue. As I have before contended, a 

 right answer to the question whether acquired characters are or 

 are not inherited, underlies right beliefs, not only in Biology and 

 Psychology, but also in Education, Ethics, and Politics. 



III. 



As a species of literature, controversy is characterised bv a 

 terrible fertility. Each proposition becomes the parent of half a 



