THE PROBLEM 43 



THEORIES OF DEATH 



On the basis of these five general classes of facts 

 which have been briefly reviewed a whole series of specu- 

 lations as to the meaning of death have been reared. The 

 first attempt at a biological evaluation* of the meaning 

 of death which attracted the serious attention of scientific 

 men was that of Weismann. In his famous address of 1881 

 on the duration of life, Weismann propounded the thesis 

 that death was an adaptation, advantageous to the race, 

 and had arisen and was preserved by natural selection. 

 Probably no more perverse extension of the theory of 

 natural selection than this was ever made. It appeared, 

 however, just at the time when the post-Darwinian at- 

 tempt to settle the problems of evolution by sheer dia- 

 lectic was at the zenith of its popularity. Nowadays such 

 a doctrine as Weismann 's would not receive so respectful 

 a hearing. 



Metchnikoff, whose views excited so much popular 

 interest some years ago, held that death was the result 

 of intoxication, arising from the absorption of putrefac- 

 tive products of the activity of intestinal bacteria. The 

 chief difficulty with this view is that it is demonstrably 

 not true; either particularly in the case of man, where 

 it can easily be shown that many statistically important 

 causes of death cannot possibly be accounted for under 

 it, or generally in the animal kingdom; because a num- 

 ber of cases are now known where a metazoan form can 

 be successfully made to lead a completely aseptic life, 

 and still death occurs at about the usual time. (Cf. Chap- 

 ter VIII). More speculative developments of the same 



* An excellent discussion of various theories of death, which the 

 writer, though differing from some of the conclusions, has found useful 

 in the preparation of this section, has lately been given by Child in his 

 "Senescence and Rejuvenescence." 



