CLASSIFICATION OF DISEASE. 27 



real advance in this particular direction in either field of 

 inquiry, of a philosophical and comprehensive character, can 

 be expected to be made. 



And although practical medicine will never suffer to be bound 

 by strict and rigid classification, description, or nomenclature, 

 still, in studying it systematically, a distinct and understood 

 system of classification of the subjects to be treated is of decided 

 advantage. 



The arrangement or classification of equine diseases which 

 seems most easily comprehended, and which for practical pur- 

 poses seems as efficient as any other, and which I shall endea- 

 vour to adhere to as closely as possible in further describing 

 these in detail, is that which regards diseases as forming tw^o 

 gTeat groups. 



Group I. — General, or systemic diseases : diseases which 

 seem to affect the entire system, or at least the greater part of 

 it, at the same time, and in which the entire functions of the 

 animal body are simultaneously disturbed. 



Group II. — Local diseases : usually sporadic diseases, in 

 which special organs or systems are primarily disturbed, and 

 in the course of which lesions tend to be localized. 



The first group is divided into two classes : 



Class A. — Fevers and some other affections, chiefly exogenous 

 diseases, depending for their development upon the operation 

 of agencies acting from without the animal body. 



Class B. — Constitutional diseases, such as appear to depend 

 upon an indwelling disposition or cachexia ; although chiefly 

 endogenous, they may result from the entrance of agencies 

 from without. 



The second group, local diseases characterized by the exist- 

 ence of particular local morbid processes, is divided into many 

 classes corresponding to the system of organs affected. 



In the first group, that of general or systemic diseases, 

 there are included diseases infectious or contagious, propagable 

 by intercourse of one animal with another, or by inoculation, 

 diseases known as epizootic or enzootic, and diseases recognised 

 as constitutional. With the exception of the last class, the 

 others are often grouped and spoken of as diseases of the 

 zymotic class. 



The exogenous class, then, of general or systemic diseases, 



