40 HEREDITY AND ENVIRONMENT 



development of the human individual, mind 

 as well as body. The animal ancestry of the 

 race is surely no more disturbing to philosophi- 

 cal and religious beliefs than the germinal 

 origin of the individual, and yet the latter is a 

 fact of universal observation which can not be 

 relegated to the domain of hypothesis or 

 theory, and which can not be successfully de- 

 nied. If we admit the fact of the develop- 

 ment of the entire individual, surely it matters 

 little to our philosophical or religious beliefs 

 to admit the development or evolution of the 

 race. 



The origin of the mind, or rather of the 

 soul, is a topic upon which there has been much 

 speculation by philosophers and theologians. 

 One of the earliest hypotheses was that which 

 is known as transmigration or metempsychosis. 

 This doctrine probably reached its greatest 

 development in ancient India, where it formed 

 an important part of Buddhistic belief; it was 

 also a part of the religion of ancient Egypt; 

 it was embodied in the philosophies of Pytha- 

 goras and Plato. According to these teach- 

 ings, the number of souls is a constant one; 



