THE BIOLOGICAL CONTROL OF LIFE 35 



cultivated Bacteria and made them serve his purposes ; 

 he gave us the secret of the conquest of many kinds of 

 diseases, and he had a Darwin-like appreciation of the 

 subtlety of inter-relations in the web of life. 



Darwin had shown that the forms of life which seemed 

 so stable were in process of racial flux — though the 

 change might be as imperceptible as the movement of 

 a glacier. The individual, moreover, was shown to be 

 plastic (technically, modifiable) for better or for worse, 

 under the influence of changed surroundings and changed 

 habits, both in the way of use and in the way of disuse. 

 Thus the whole aspect of things was changed. The 

 outlook became vividly dynamic, and the idea of the 

 controllability of life began to grip. If flowers and 

 pigeons can be controlled so effectively, then why not 

 human life also ? If Man can evolve out of some sort of 

 wolf the domesticated dog, the dependable guardian of 

 the flocks, may he not hopefully try to evolve the 

 wolfish out of himself ? Are there not organic shackles 

 which may be dealt with biologically, setting Man free for 

 higher adventures ? When men were asking such 

 questions, usually in a half-convinced way, Pasteur 

 began a series of achievements which were inspired by 

 the idea of the biological control of life. Beginning 

 with the silkworm disease, which was ruining the South 

 of France, he advanced to such terrible maladies as 

 splenic fever and hydrophobia, conquering by under- 

 standing. With object-lessons on a grand scale he 

 convinced all intellectual combatants who cared to 

 understand that the days of fatalism and folded hands 



