106 AGE, GROWTH, AND DEATH 



demonstrates this fact, for in the female we find 

 exactly the same phenomena, as the next slide will 

 show. The irregularities are not significant. The 

 strange dip at thirty-eight days, for instance, corres- 

 ponds to an illness of some of the rabbits which were 

 measured, but they rapidly recovered from it and 

 grew up to be fine, nice rabbits. If instead of measur- 

 ing half a dozen rabbits, we had measured two 

 hundred or five hundred, these irregularities would 

 certainly have disappeared. The females in the case 

 of the rabbits, as in the case of the guinea-pigs, are 

 not able to grow quite so fast at first. We see here 

 sixteen instead of over seventeen per cent, as the 

 initial value, but the general character of the drop is 

 the same, enormously rapid at first and very slow 

 afterwards. All of our cases, then, show the same 

 fundamental phenomena appearing with different 

 values. 



Now in regard to man, we do not possess any such 

 adequate series of statistics of growth as is desirable. 

 We have many records of the weight of babies, by 

 which I mean children from the date of birth up to 

 one year of age. We have also very numerous re- 

 cords of school children, which will extend perhaps 

 from five and one half up to say seventeen, eighteen, 

 or even nineteen years. There are records of boys 

 at universities, and a still more limited number of 

 weighings of girls at colleges. But all these statistics 

 piled together do not give us one comprehensive set 

 of data including all ages. This is very much to be 



