232 WORLD-POWER AND EVOLUTION 



upon the deathrate and hence upon human energy. Remember 

 that the brain is the most sensitive of man's organs and that 

 climatic changes were apparently the greatest external factor in 

 controlling its development. Remember, too, that among all the 

 faculties of the human mind none is so sensitive to external cir- 

 cumstances as is the power of invention. Do we not all know 

 that an interruption bothers us far more when we are trying to 

 solve some difficult problem than when we are merely doing a bit 

 of routine figuring? Is it not notorious that people who are 

 gifted with the creative impulse, whether in art, music, literature, 

 or science, are more sensitive than any others to conditions of 

 health? In rare cases like Darwin, and Stevenson in his later life, 

 a man succeeds in doing a great work in spite of ill health. Ask 

 an ordinary scientist, however, as to the effect of a Headache when 

 he is trying to write the report of some complex investigation. 

 Many a time I have heard my colleagues say that on days when 

 they feci right they can do five times as much as when something 

 is wrong with their health. Often such a man throws away what he 

 has written at such a time, and rewrites when he feels more '*fit." 



This may seem like a digression from Russia, but it is not. 

 Having lived for over a year among the Russians, and having 

 learned to admire both the common people and their great men, 

 I would be the last to underrate them. Yet many of my Russian 

 friends have made a remark which my own observation fully bears 

 out : "We Russians are not like you Anglo-Saxons. We are more 

 sensitive to external impressions. We lack your power of con- 

 centration. That is our greatest trouble. We become filled with 

 high ideals, or with great plans for remodelling the world. We 

 begin on them with great enthusiasm, but we do not stick to them. 

 Fits of depression come over us, and when we are close to a great 

 achievement we often give up in despair." 



Presumably this is in part, at least, a Slavic characteristic. 

 Yet after observing the effect of the weather in New York and 

 in many other regions, I cannot but think that climate and health 



