TIME REQUIRED FOR THE DEVELOPMENT OF MAN. 3 



beginning this task, it will be "well to note a few other 

 general facts which may enable us better to understand the 

 phenomena we are about to study. 



Firstly, it may not be out of place to insert a few 

 remarks as to the duration of time during which Man was 

 developing from the animal kingdom. The first thought 

 that occurs to the mind when we consider the facts in 

 question, is of the immense difference between the duration 

 of the germ-history of Man on the one hand, and of his 

 tribal history on the other. The brief period in which the 

 Ontogeny of the human individual takes place, bears no 

 proportion to the infinitely long period required for the 

 Phylogeny of the human tribe. The human individual 

 requires nine months for its perfect development from the 

 fertilized egg-cell to the moment at which it is born and 

 quits the mother's body. The human embryo, therefore, 

 passes through the whole course of its development in the 

 brief space of 40 weeks (usually in exactly 280 days). 

 Each man is really older by this period than is usually 

 assumed. When, for example, a child is said to be 9j years 

 old, he is in reality 10 years old. For individual existence 

 does not begin at the moment of birth, but at the 

 moment of fertilization. In many other Mammals the 

 duration of the embryonic development is the same as in 

 Man, e.g., the Ox. In the Horse and the Ass it is somewhat 

 longer, viz., from 43 to 45 weeks; in the Camel it is 13 

 months. In the largest Mammals the embryo requires a 

 much longer time for its complete formation within the 

 maternal body; in the Rhinoceros, for instance, l^^ year, 

 in the Elephant 90 weeks. In the latter case, therefore, 

 gestation lasts more than twice as long as in Man — for 



