Experiments on Lenses 171 



refuse its aid. In his Variation of Animals and Plants 

 under Domestication he contrasts, for instance, the 

 skeletons of wild and domestic ducks, and explains the 

 relatively smaller size of the bones of the wing in the 

 domesticated forms as due to the fact that they have 

 been reared for generations during which the wings 

 have been used little, if at all. Whether Darwin's re- 

 tention of the Lamarckian view is an illustration of 

 prescience or of acquiescence remains doubtful, and 

 we shall have one reason to be grateful to rats if they 

 assist in answering this question. 



EXPERIMENTS ON EENSES 



Very remarkable experiments have been made by 

 Professor M. F. Guyer and E. A. Smith on the eyes 

 of rabbits. Lens tissue from rabbits was pulped, made 

 into an extract, and injected into fowls. It excited 

 in the blood of the fowl the production of specific 

 "anti-bodies" — that is to say, chemical counter- 

 actives to the deleterious intruded material. Now, if 

 the serum of the fowl's blood be injected into preg- 

 nant rabbits, the contained anti-bodies sometimes 

 attack the lenses of the unborn young and produce 

 serious deterioration. But the injurious effects on 

 the lens were also observed in very pronounced form 

 in a second generation of rabbits which had not been 

 subjected to any interference. The eye defects may 

 be transmitted for several generations, by males as 

 well as by females ; and the defects may even increase 

 in amount. The explanation may be that the dete- 

 rioration or degeneration of the eyes of the first 



