Chapter I 



THE PROBLEM 



(1) The struggle for existence is one of those questions which were 

 very much discussed at the end of the last century, but scarcely any 

 attempt was made to find out what it really represents. As a result 

 our knowledge is limited to Darwin's brilliant exposition, and until 

 quite recently there was nothing that we could add to his words. 

 Darwin considered the struggle for existence in a wide sense, includ- 

 ing the competition of organisms for a possession of common places 

 in nature, as well as their destruction of one another. He showed 

 that animals and plants, remote in the scale of nature, are bound 

 together by a web of complex relations in the process of their struggle 

 for existence. "Battle within battle must be continually recurring 

 with varying success," wrote Darwin, and "probably in no one case 

 could we precisely say why one species has been victorious over 

 another in the great battle of life. ... It is good thus to try in imagina- 

 tion to give to any one species an advantage over another. Probably 

 in no single instance should we know what to do. This ought to 

 convince us of our ignorance on the mutual relation of all organic 

 beings; a conviction as necessary as it is difficult to acquire. All that 

 we can do, is to keep steadily in mind that each organic being is 

 striving to increase in a geometrical ratio; that each at some period 

 of its life, during some season of the year, during each generation or at 

 intervals, has to struggle for life and to suffer great destruction" 

 ('59, pp. 56-57). 



(2) But if our knowledge of the struggle for existence has since 

 Darwin's era increased to an almost negligible extent, in other do- 

 mains of biology a great progress has taken place in recent years. 

 If we look at genetics, or general physiology, we find that a decisive 

 advance has been made there, after the investigators had greatly 

 simplified their problems and taken their stand upon the firm basis 

 of experimental methods. The latter presents a particularly interest- 

 ing example about which we would like to say a few words. We 

 mean the investigations of the famous Russian physiologist J. P. 

 Pavlov, who approached the study of the nervous activity of higher 



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