380 



Royal Society . 



Litters subsequent to cross-circulation of both parents (Silver-greys). 

 Average proportion of alienized blood in young fully j. 



Litters subsequent to cross-circulation of both parents (common 

 rabbits). Average proportion of alienized blood in young a 

 little less than ^. 



I will now summarize the results. In the first instance I ob- 

 tained five does (A, B, C, D, and E) and three bucks (K, L, and M) 

 which had undergone the operation which I call ?<, and which had in 

 consequence about ^ of their blood alienized. I bred from these f, 

 partly to see if I had produced any effect by the little I had done, 

 and chiefly to obtain a stock of young rabbits which would be born 

 with g of alien gem mules in their veins, and which, when operated 

 upon themselves, would produce descendants having nearly \ alienized 

 blood (the exact proportion is 1 — (1 — a)' — M)- ^ obtained thirty 

 young ones in six litters ; and they were all true silver-greys, except, 

 possibly, in one instance (out of the doe A (?<) by the buck M {u)), 

 where one, of a litter of five, had a white fore leg, the white extending 

 to above the knee-joint. This white leg gave me great hopes that 

 Pangenesis would turn out to be true, though it might easily be 

 accounted for by other causes; for my stock were sickly (both those 

 on which I had not operated and those on which I had suffering 

 severely from a skin disease), and it was natural under those cir- 

 cumstances of ill health that more white than usual should appear in 

 the young. 



* These rabbits belong to a breed liable to tlirow " Sandy " Himalayas. 



t I always allowed the bucks to run for awhile with waste does before com- 

 mencing the breeding-experiments, that all old reproductive material might be 

 got rid of. 



