A SCIENTIFIC EXPLANATION OF LIFE 87 



constellation differs in the number and movement of its constituent 

 electrons from the oxygen constellation, and that both constellations are 

 differently related to the rest of the world, but why one set of relation- 

 ships should be hydrogen and the other oxygen would be revealed to 

 him as little as it will ever be revealed to the biologist why one kind of 

 corpuscular movement in the brain means pleasure, whereas another 

 means pain. 



Unfortunately, the biologist has no more senses than any other man ; 

 all that he tries to do is to use those he has to the best of his ability. 

 It so happens that the senses with which he learns, and the brain with 

 which he reflects, have evolved from simpler conditions, but however 

 different the early stages of these organs may have been, they were 

 elements in the fitness of his progenitors, and he believes that his 

 natural endowments, limited though they be, are no less serviceable to 

 himself and his fellows now than they were in pre-historic days. To- 

 day more than at any previous time in the history of civilization it is 

 coming to be recognized that the results of the application of our senses 

 to the study of nature are racially essential. Another and closely related 

 truth, however, still has to fight hard for its daily bread, for it is 

 unfortunately by no means generally known that scientific results are 

 not, and can not be, got directly for the asking. Most men of his day, 

 had they known about it, would have considered James Watt a fool, for 

 instead of watching the steaming mouth of a tea-kettle, a thing which 

 millions of men had seen before, and have seen since, and to no partic- 

 ular advantage either, he might have been occupied with the more 

 obviously useful task of chopping wood for the fire; yet to these fire- 

 side dreams we can trace the whole of modern travel by steam. Perhaps 

 Gregor Mendel, in the opinion of those who saw him pottering over his 

 peas, would have done better to devote more time still to the affairs of 

 his extraordinarily well-run abbey, yet upon his careful, thoughtful and 

 beautiful observations rests the modern science of heredity, and the hope 

 for the betterment, not only of our plants and animals, but of our very 

 selves. Perhaps the man who hunts for frog spawn in the early spring 

 would be better occupied removing the ashes from his cellar, yet it was 

 a man with just this vagary whose tadpoles not only enlightened him 

 and all the world as to the manner in which nerve fibers grow, but the 

 methods developed in the course of these studies are now being applied 

 for the purpose of determining the conditions under which cancerous 

 growths occur, and consequently are freighted with the possibility of 

 both the prevention and cure of this terrible scourge of middle and 

 old age. 



This is the method by which scientific explanations and their appli- 

 cation come about, and however much we may regret that knowledge 

 does not grow more simply and directly, the reason for this lies in the 



