34^ LIFE AND DEATH. 



La Bruyere expresses it in an apothegm, "We want 

 to grow old, and we fear old age." One would like 

 longevity without old age. 



But can life be prolonged without senility diminish- 

 ing its value? Metchnikoff thinks it can. He 

 more or less clearly catches a glimpse of a normal 

 evolution of existence which would make it longer 

 and nevertheless exempt from senile decay. 



It is remarkable that we have so few scientific data 

 on the old age of man, and we have still few er on 

 that of animals. The biologist know s no more than 

 the layman. The old age of the dog is betrayed by 

 its gait. Its coat loses its lustre, just as in disease. 

 The hair whitens around the forehead and the 

 muzzle. The teeth grow blunt and drop out. The 

 character loses its gaiety and becomes gloomy; the 

 animal becomes indifferent. He ceases to bark, and 

 often becomes blind and deaf. 



It is admitted that senile degeneration is due to an 

 alteration affecting most of the tissues. The cells, 

 the special anatomical elements of the liver, the 

 kidney, and the brain are reduced by atrophy and 

 degeneration. At the same time, the conjunctive 

 woof which serves them as a support develops, on 

 the contrary, at the expense in a measure of the 

 higher elements. For this reason the tissues harden. 

 We know that the flesh of old animals is tough. We 

 know in pathology that this is happening to the 

 tissues. It is due to growth, to injury to the 

 active and important elements, to the elements of 

 support of the organs. They form a tissue some- 

 times called packed tissue, to show its secondary role 

 with reference to the elements which are deposited 

 in it. This kind of degeneration of the organs is 



