THE INSTINCT OF SURVIVAL 101 



elements of the nervous system itself are endowed 

 with only a very limited capacity for defense that 

 the survival powers of nervous tissues are small as 

 compared with those of glandular organs. There 

 thus appears a well-defined differentiation of the 

 organism in relation to the self-preservative instinct 

 in general, the nervous system expressing in its 

 manifold adjustments not merely the reactions of 

 adaptation to the outer world, but also the adapta- 

 tions especially demanded by the active cells of the 

 body. The instinct in its narrow sense may be said 

 to reside especially in the nearly defenseless nervous 

 system, whereas the ultimate powers of defense 

 which we are assuming to be the basis of the survival 

 instinct lie chiefly in the glandular cells, inex- 

 pressive, and relatively insentient in the ordinary 

 meaning of these words. And I think that we are 

 safe in believing that just as the general body cells 

 with their rich endowment of survival powers find 

 in the nervous system their agent for instinctive 

 demonstrations, so the sexual cells with their repro- 

 ductive powers find an expressional outlet through 

 the nervous system in those feelings and acts anti- 

 thetical in many ways to the personal survival 

 instincts which we interpret as the sexual instinct. 

 The most fundamental expression of the self- 

 preservative instinct is the appetite for food, an 

 admirable example of a nervous expression of the 

 needs of the body or somatic cells. We must 

 comment on some of the effects of this appetite. 



