SELF-PRESERVATION AND THE MENTAL LIFE 157 



substances capable of injuring the brain. The 

 damage done the nervous system in this way still 

 further depresses the digestive secretions, and in 

 this manner a vicious circle is established, which it 

 may be very difficult to break. Nervous disorders 

 of a depressive kind and blood disorders are the 

 commonest results of such conditions, if they be long 

 continued. The effects of excessive intellectual ap- 

 plication are similar to those of sexual excitement, 

 for, like these, they depend primarily on nervous 

 exhaustion. But they are, in general, less pro- 

 nounced and are, from the nature of things, much 

 less frequent. Very similar effects, too, result from 

 a life characterized by appeals to the emotional side 

 of human nature. An excessively emotional life is 

 very common in the competition of the ordinary 

 business life, very common, also, in the struggles for 

 social success which form so important a part of the 

 modern life of women. When people become aware 

 of the dangerous nature of the demands which are 

 made upon them by these emotional expenditures 

 and those incidental to sexual experience, they will 

 strive to keep them within reasonable limits. And 

 it will then be seen that in the endeavor to do 

 this there will be a nearer approach to the realiza- 

 tion of the best standards of conventional ethical 

 teaching. 



II 



The effects of suggestion on mental life are so 

 powerful and far-reaching that they cannot safely be 



