62 



GROWTH 



family, the simultaneous presence of several dependent chil- 

 dren of different ages, is based on this fact. With the beginning 

 of puberty, however, the difference between man and animals, 

 as far as the shape of the curve is concerned, disappears. 



fctt-f; Scale 



Figure 42. An equivalence chart of man and animals. The curve of man is conspicuous 

 for its extraordinarily long juvenile period. 



VI. Death 



It is hardly possible to discuss growth and senescence without 

 at the same time thinking of death, for death is the natural con- 

 comitant of growth and senescence. Someone has said, with 

 much truth, that we begin to die the moment we are born. 



The various theories of death have been recently summarized 

 and discussed with much insight by Raymond Pearl in his 

 monograph on the Biology of Death, and we need not therefore 



