590 DISHARMONIES AND OTHER SHADOWS 



enlightened understanding of the limitations and dis- 

 harmonies of his constitution, he would no longer, as Buffon 

 said, die of disappointment, but would attain everywhere a 

 hundred years. 



The second point is not less important. As Professor 

 Humphrey, a specialist on old age, has said, '^ Strange and 

 paradoxical as it may seem, this gradual natural decay and 

 death, with the physiological processes which bring them 

 about, do not appear to present themselves in the ordinary 

 economy of nature, but to be dependent upon the sheltering 

 influences of civilisation for the opportunity to manifest 

 themselves, and to continue their work." The fact is that 

 man and some of his domestic animals have almost a monop- 

 oly of senility, while wdld animals rarely show a trace of 

 it. Thus senility is not disharmony in Nature, but in the 

 Kingdom of Man. 



The bathos often seen in man is due partly to the way in 

 which he shelters himself from violent or extrinsic death, 

 which cuts off so many — if not most — animals ; partly to the 

 unnatural ways in which he lives ; and partly to his deficiency 

 in the resting instinct. 



It is instructive to probe the matter further, inquiring 

 into the reasons not for senility, but for senescence and 

 natural death. There is an obvious distinction between (a) 

 death due to microbes or parasites, (h) death due to extrinsic 

 agencies or violence, and (c) death due to internal constitu- 

 tional reasons; it is with the last, natural death and its 

 antecedent senescence, that we have to do. To the question: 

 Why should an organism grow old ?, many answers have been 

 given. A reason has been found in the wear and tear of 

 parts, especially of elements like nerve-cells, which do not 

 in higher animals increase in number, nor admit of renewal, 



