296 MEMORIES OF MY LIFE 



more fully gone into here ; I must refer to the Memoir 

 itself. The general result of the inquiry was to 

 support the views of those who hold that man is little 

 more than a conscious machine, the slave of heredity 

 and environment, the larger part, perhaps all, of 

 whose actions are therefore predictable. As regards 

 such residuum as may not be automatic but creative, 

 and which a Being, however wise and well-informed, 

 could not possibly foresee, I have nothing to say, but 

 I found that the more carefully I inquired, whether it 

 was into hereditary similarities of conduct, into the 

 life-histories of twins, or introspectively into the 

 actions of my own mind, the smaller seemed the 

 room left for this possible residuum. 



Many possibilities suggested themselves after 

 reading Darwin's "Provisional theory of Pangenesis." 

 One was that the breed of a race might be sensibly 

 affected by the transfusion of blood from another 

 variety. According to Darwin's theory, every element 

 of the body throws off gemmules, each of which can 

 reproduce itself, and a combination of these gemmules 

 forms a sexual element. If so, I argued, the blood 

 which conveys these gemmules to the places where 

 they are developed, whether to repair an injured part 

 or to the sexual organs, must be full of them. They 

 would presumably live in the blood for a considerable 

 time. Therefore, if the blood of an animal of one 

 species were largely replaced by that of another, 

 some effect ought to be produced on its subsequent 

 offspring. For example, the dash of bull-dog tenacity 

 that is now given to a breed of greyhounds by a 

 single cross with a bull-dog, the first generation cor- 



