T 229 



thyck's walking-engine from the fuel in its furnace. As 

 regards matter, the animal body creates nothing ; as re- 

 gards force, it creates nothing. Which of you by tak- 

 ing thought can add one cubit to his stature ? All that 

 has been said regarding the plant may be re-stated with 

 regard to the animal. Every particle that enters into 

 the composition of the muscle, a nerve, or a bone, has 

 been placed in its position by molecular force. And 

 unless the existence of law in these matters be denied, 

 and the element of caprice be introduced, we must con- 

 clude that, given the relation of any molecule of the 

 body to its environment, its position in the body might 

 be predicted. Our difficulty is not with the quality of 

 the problem, but with its complexity ; and this difficulty 

 might be met by the simple expansion of the faculties 

 which man now possesses. Given this expansion, and 

 given the necessary molecular data, and the chick might 

 be deduced as rigorously and as logically from the egg 

 as the existence of Neptune was deduced from the dis- 

 turbances of Uranus, or as conical refraction was de- 

 duced from the undulatory theory of light. 



You see I am not mincing matters, but avowing 

 nakedly what many scientific thinkers more or less dis- 

 tinctly believe. The formation of a crystal, a plant, or 

 an animal, is in their eyes a purely mechanical problem, 

 which differs from the problems of ordinary mechanics in 

 the smallness of the masses and the complexity of the 

 processes involved. Here you have one half of our 

 dual truth ; let us now glance at the other half. Asso- 

 ciated with this wonderful mechanism of the animal 

 body we have phenomena no less certain than those of 

 physics, but between which and the mechanism we dis- 

 cern no necessary connection. A man, for example, 



