102 



AGE, GROWTH, AND DEATH 



which the first, from nine down to three, would be 

 two thirds, and the second, from three to zero, would 

 be one third. Here then we learn that two thirds of 

 the decline which occurs in the life of a chick takes 



CJucb 



OJS8I3I82ZJ8333846 56 66 " 90 K)6 



IdauJ 



FIG 34. CURVE SHOWING THE DAILY PERCENTAGE INCREMENTS IN WEIGHT 

 BY FEMALE CHICKENS. 



place in two months, and for the rest of the life of the 

 bird there is a decline of one third. That, you must 

 acknowledge, is an extraordinary and most impressive 

 difference. 



If it be true that the more rapid growth depends 

 upon the youth of the individual, its small distance 

 in time from its procreation, then we may perhaps, 

 by turning to other animals which are born in a more 

 immature state, get some further insight into these 

 changes ; and that I have attempted to do by my ob- 

 servations upon the development of rabbits. 1 Rabbits, 



1 See Appendix No. I. 



