376 THE BIOLOGY OF THE SEASONS 



trated in young men under twenty, we may regard senile 

 degeneration as an unnecessary incident of old age ! 



Let us face the question : Why should wild animals 

 show so little trace of senility, which is often marked in 

 domesticated or captive animals ? why should they rarely 

 exhibit more than a slight senescence, while man often 

 exhibits a bathos of senility ? 



In reference to the contrast between wild animals and 

 those tamed or in captivity, we have to remember that the 

 former seem usually to die a violent death before or after 

 old age has set in, but almost always before there has been 

 time for senility. From such violent death man more or 

 less protects the pet horses, dogs, cats, etc., whose life has 

 become entwined in his affections. Furthermore, while 

 natural death is due to the accumulation of physiological 

 bad debts, the character of the old age depends upon the 

 nature of these bad debts. Some are much more unnatural 

 than others ; they are much more unnatural in tame than 

 in wild animals. 



As to man, in particular, let us recall a few facts which 

 may explain why he is unhappily notorious as the best 

 illustration of senility, (a) Being sheltered by Reason 

 from most of the extreme physical forms of the struggle for 

 existence, he can live for a long time with a very defective 

 hereditary constitution, which may end in a period of 

 undesirable senility, (b) Endowed as he is with Reason 

 the capacity for handling general ideas and regulating his 

 conduct in reference thereto man, especially in highly 

 civilised communities, is very deficient in the resting 

 instinct, and seldom takes much thought about resting 

 habits. A simple creature exhausts its stores of internal 

 fuel, the nervous system gives the signal " Hunger " or 

 " Fatigue," and infallibly the simple creature will eat or 

 rest if it can. Its brain is not disobedient. In higher 



