Cunningham, Unisexual Inheritance. 37 



should rny view be supposed to account for the limitation of the mule 

 characters to the male, and the former view (Darwin's) to fail. He 

 then repeated Wallace's suggestion that the female being in greater 

 need of concealment had had any tendency to inherit the male cha- 

 racters eliminated by natural selection. These criticisms seem to me 

 to show that my critic had failed lo understand not only my theory 

 but Darwin's. Darwin did not even attempt to explain the uni- 

 sexual limitation, but pointed out that the variations must have been 

 unisexually limited before they were selected. It is not a question of 

 niy explanation versus Darwin's but of mine versus none. Mine is a 

 theory of the origin of certain variations, Darwin's a theory of their 

 preservation. Professor Meldola does not show in what way or for 

 what reason my hypothesis fails to explain the facts, he merely asserts 

 that it fails. When in a correspondence in ,,Nature" I put forward 

 some arguments in explanation of my position, Professor Meldola 

 urged that my theory could not be true, because as I myself admitted, 

 male characters were in certain cases developed also in the female 

 as for instance in the Reindeer. My theory is intended to explain first 

 and foremost secondary sexual characters of the most typical kind, 

 which I defined as those which are affected by castration, which do 

 not develop normally after removal of the generative organs. Whether 

 such characters may ultimately be transferred to both sexes, or whether 

 unisexual characters exist which are independent of the condition of 

 the generative organs are secondary questions which do not necessarily 

 invalidate my theory of the origin of the typical cases. 



Professor Meldola at once attacked my definition, and stated 

 that so far as he knew there was no single observation, with the ex- 

 ception perhaps of Stylopised bees, which would bring the sexual 

 characters of fishes, reptiles, Crustacea, insects etc., within its scope, 

 and asked: ,,Is there any known case among these lower groups, 

 where the removal of the generative organs leads to the appearance 

 of the characters of one sex in individuals of the other sex?" Now 

 from the facts collected by Darwin and those added by myself it is 

 fully proved that in the lower classes to which Professor Meldola 

 refers, unisexual characters as a general rule are not developed until 

 the approach of sexual maturity, and the selfevident similarity of the 

 phenomena in these lower animals with those seen in mammals and 

 birds, justifies the conclusion that in the former also the development 

 of the characters is physiologically correlated with the normal action 

 of the reproductive organs. Professor Meldola's argument that my 

 definition cancels at least half my own book would only be sound if 

 he had proof that removal of the generative organs did not prevent 

 the normal development of unisexual characters in fishes, reptiles, 

 Crustacea, etc. 



