PREFACE. 



My excuse for perpetrating this work consists 

 in shifting the blame on the students who so 

 often have asked me to recommend something 

 that could he studied without necessitating the 

 perusal of many pages. And so this is the result. 

 I lay claim to but little originality, although 

 what I have told is the result of conscientious 

 study, supplemented by practice, both private and 

 clinical, and careful observation. Let me hope, 

 therefore, that my motives will be taken into 

 consideration by any critic who may deem this 

 publication worthy of notice. 



