THE INSTINCT OF SURVIVAL 113 



ideation, and emotional life gradually decline despite 

 of it. These alterations in the spiritual sphere are 

 attributable to a slow atrophy of the brain, partic- 

 ularly of the cellular elements of the cortex. There 

 is, in general, a decadence in character, although this 

 may be so slight in degree as to escape the notice of 

 indulgent companions. Perhaps the mam evidence 

 of this is a certain loss in sympathy and consider- 

 ateness for others which is a part of the growing 

 callousness. The change is, in some respects, like 

 that which is witnessed in the wasting of the cortical 

 substance in the disease known as general paresis, 

 though much slighter in degree. 



Ill 



If life be worth living, it is logical to yield to the 

 instinct to prolong it, so long, at least, as any satis- 

 faction can be got from it or given by it. And, 

 giving way to this instinct, people have, for cen- 

 turies, striven to increase the number of their days, 

 sometimes by rational methods, too often by resort 

 to unintelligent measures, unfounded either in 

 reliable empiricism or in correct theory. It may 

 justly be claimed for modern medical science that 

 it has gone far to show mankind what it may expect 

 in promise of life, and on what sources its expecta- 

 tions must be based. The last word has certainly 

 not been uttered on this subject, but the possibilities 

 can, with some confidence, be defined. It is true 



