EMBRYOLOGY. 101 



more length of life available for further 

 developments. 



The young of the Herbivora can run and crop 

 the herbage immediately after birth, and are 

 therefore born with their senses and faculties, 

 far more perfect than those of the young of the 

 higher orders of Mammalia. The Herbivora, 

 are animals of very ancient origin, and must 

 certainly have preceded the Carnivora and 

 Quadrumana ; and it is therefore reasonable to 

 suppose that they are at present more highly 

 developed on their own plane than the more 

 modern orders. Thus there is nothing extra- 

 vagant in the idea of the late J. W. Jackson, that 

 in the future course of human development, men 

 will be born with all their faculties, both bodily 

 and mental, developed to an extent which would 

 appear incredible to us at the present day. * It 

 has been calculated that according to the length 

 of time required by man to reach maturity, the 

 natural length of -his life should be 120 years. 

 If this reasoning is correct, we may hope that 

 the actual length of human life (the average of 

 which has been steadily rising in Europe for the 



* "Man," pp. 87100. 



