372 THE BIOLOGY OF THE SEASONS 



Montaigne says of his father : "I have seene him, when 

 hee was past threescore years of age, mocke at all our 

 sports, and out-countenance our youthfull pastimes, with 

 a heavy furr'd gowne about him leap into his saddle ; to 

 make the pommada round about a table upon his thumb ; 

 and seldome to ascend any stakes without skipping three 

 or foure steps at once." We have known a venerable 

 naturalist of seventy-five make the ascent of Schiehallion, 

 and walk eight miles besides, without a trace of ill effects. 

 Similar examples are familiar to all, and they represent the 

 ideal, doubtless quite attainable, defiance of senility. 

 They illustrate the contrast between senility and senescence. 



Senescence is the normal process of growing old, as we 

 see it in constitutionally strong men who have lived very 

 healthful lives (within or without civilisation), and in those 

 wild animals that live to a great age in natural conditions. 

 Senility is the process of marked degeneration, which is 

 often seen in old age (and sometimes long before it). And 

 the biological fact which seems to us of most importance 

 is the striking one that man and his domesticated animals 

 have almost a monopoly of senility, while wild animals 

 rarely show any trace of it. 



It may be said that most wild animals die a violent 

 death in the majority of cases before they exhibit even 

 senescence. But some live to a great age, and the im- 

 portant fact is the practical absence of senile degeneracy, 

 except in relatively unimportant parts, such as the teeth. 

 Apart from captive carp and the like, which must be dis- 

 counted, fishes that have demonstrably lived for a great 

 many years (as the rings on their scales, bones, and ear- 

 stones show) do not exhibit any trace of senile degeneration. 

 Dr. F. Werner, an expert student of reptiles, emphasises 

 the fact that even in giant specimens of crocodile and snake 

 " no trace of senile degeneration could be detected." 



