128 AGE, GROWTH, AND DEATH 



man before birth as far as it can be determined without 

 better knowledge than I have at command. The time 

 intervals in the diagram correspond to the so-called 

 lunar months the ten lunar months of prenatal life. 

 Of our early development we know very little so far 

 as statistics are concerned, but from the third month 

 onward we have some records. It is found that from 

 the third to the fourth month the increase is 600 per 

 cent. Just contrast that with 200 per cent, added in one 

 year after birth ; 600 per cent, in one month against 200 

 per cent, in one year. From the fourth to the fifth 

 month it is scarcely over 200 per cent. It then becomes 

 only a little more than 100. In the seventh month, less 

 than 100 ; and finally in the ninth and tenth months, it 

 becomes very small indeed, less than 20, so that during 

 the prenatal life of man, as we have seen in the prenatal 

 life of the rabbit and of the chick the decline in the 

 power of growth is going on steadily all the time. 



I "Shall use the few remaining moments to report 

 to you yet another bit of evidence of the originally 

 enormous power of growth. It has been estimated 

 that the germ of the mammal, with which the devel- 

 opment commences, has a weight of 0.6 milligram ; 

 another estimate which I have found is of 0.3 milli- 

 gram. 1 Perhaps I can give you some idea of what 

 this value means by telling you that if the weight of 

 the original germ of a mammal is assumed to be 0.6 



1 These estimates refer to the placental mammals only. My authorities are 

 M. Miihlmann, Ueber die Ursache des Todes, 1900, p. 45, and Donaldson, 

 Growth of the Brain, 1895, p. 60. 



