8o THE EVOLUTION OF DEATH 



same as that which we meet on a larger scale in the ccelen- 

 terates. 



Has death a purpose? Weissmann has expressed the 

 interesting thought that death is advantageous to organisms. 

 If an organism lived forever it would become, through acci- 

 dents, more and more injured. By death this is avoided, and 

 at the same time by continuous reproduction the creation of 

 new healthy individuals is provided for. I am, however, not 

 inclined to regard death in itself as advantageous, but rather 

 as a consequence of differentiation. The higher plants and 

 animals have arisen through differentiation to it we are 

 indebted for our organization which makes us men; to it we 

 owe the possibility of knowing our earth, its inhabitants, and 

 ourselves; to it we owe all advantages of our existence; to it 

 we owe the possibility of carrying on our physiological work 

 much better than the lower organisms; to it we owe the possi- 

 bility of those human relations which are the most precious of 

 our experiences. These advantages and many others do we 

 owe to differentiation, the price of which is death. The price 

 is not too high. None of us would like to return to the condi- 

 tion of a lower organism which might be capable of continuing 

 its species, and which had to suffer death only through acci- 

 dent. We pay the price willingly. Natural death comes, as 

 we now know, when an essential part of the body yields. It 

 may be the brain; it may be the heart; it may be another 

 organ, in which the cytomorphosis goes so far that the organ 

 can no longer perform the work assigned to it, and when it 

 fails it brings the whole to rest. Thus the conception of 

 death shapes itself in our minds. The mystery remains. The 

 biologist knows the essence of death no better than the essence 

 of life. We say of certain bodies that they live, of others 

 that they are dead. Science at present is incapable of telling 



