144 Darzvin, and after Darwin. 



would furnish a crucial test as to the inheritance or 

 non- inheritance of acquired characters. Therefore 

 I devoted to it a large share of my attention, and 

 tried the experiment in several different ways. But 

 I was never able to get the foreign ovary — or even any 

 portion thereof— to graft. Eventually the passing of 

 the Vivisection Act caused me to abandon the whole 

 research as far as animals were concerned — a research, 

 indeed, of which I had become heartily tired, since in 

 no one instance did I obtain any adhesion. During 

 the last few years, however. I have returned to these 

 experiments under a licence, and with antiseptic 

 precautions, but with a similar want of success. 

 Perhap.s this prolonged and uniformly fruitless expe- 

 rience may now have the effect of saving the time of 

 other physiologists, by warning them off the roads 

 where there seems to be no thoroughfare. On the 

 other hand, it may possibly lead some one else to 

 try some variation in the method, or in the material, 

 which has not occurred to me. In particular, I am 

 not without hope that the transplantation of ovaries 

 in very young animals may eventually prove to be 

 physiologically possible; and, if so, that the whole 

 issue as between the rival theories of heredity will 

 be settled by the result of a single experiment. 

 Possibly some of the invertebrata will be found to 

 furnish the suitable material, although I have been 

 unable to think of any of these which present 

 sufficiently well-marked varieties for the purpose. 

 But, pending the successful accomplishment of this 

 particlar experiment in the grafting of any animal 

 tissue, I think it would be clearly unjustifiable to 

 conclude .i"Ainst tlu Lamarckian factors on the 



