INTRODUCTION. 3 



ology had never availed itself of the opportunities afforded 

 by experimentation upon the lower animals, as a science 

 it would be more than emasculated; indeed it is doubtful 

 if it wovild ever have been bom. 



Neurology, not less than these other two sciences, is 

 dependent upon the comparative method for its guiding 

 principles, though the medical profession as a whole has 

 been slow to seize the opportunities thus afforded. Any 

 one who will take the trouble to examine the instruction 

 in the anatomy of the brain in many of our medical 

 colleges (and until very recently in some of the best of 

 them) will find the justification for this latter remark. 

 A glance at the works of Edinger and the other apostles 

 of the comparative method should convince the most 

 skeptical that it is impossible to understand, much 

 less to teach intelligibly, the complexity of the adult 

 human brain without reference to the simpler and more 

 diagrammatic types presented by the lower vertebrates. 

 This is undoubtedly the most valuable advantage to be 

 derived from the study of comparative neurology. 



From our standpoint, however, in a system of correlated 

 sciences for the study of abnormal mental and nervous 

 life the most important function of comparative neurology 

 lies in its value as a method of research. Of primary im- 

 portance in the investigation of the phenomena in this 

 domain, as in all life phenomena, is the method of path- 

 ology. By the use of this method the phenomena restricted 

 within the limits of the normal are given a wider range, 

 are magnified. It is obvious that we are thus enabled 

 to get a deeper insight into the nature of the phenomena 

 and have a broader basis to form inductions which are 

 more secure in proportion to the extent of territory from 

 which they are drawn. 



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