THE HORSE DISTEMPER. 145 



THE CATARRHAL EPIDEMIC. 



BY PROFESSOR D. D. SLADE, M. D., BUSSEY INSTITUTION. 



M7\ Chairman and Gentlemen : — I present a few practical 

 observations upon the epidemic which has prevailed so exten- 

 sively among horses throughout the northern and other por- 

 tions of this continent, and which is known under a variety 

 of. names, — such as influenza, distemper, epidemic catarrhal 

 fever, catarrhal epidemic, typhoid laryngitis, &c. 



What is to be understood by the term epidemic, or more 

 properly, in this connection, epizootic? — the former word 

 signifying "among the people," the latter "among the ani- 

 mals." Epidemic diseases are those Avhich attack at or about 

 the same time a number of individuals collected within a cer- 

 tain district. The laws which govern them, and the causes 

 to which they owe their origin, are far from being under- 

 stood. Scientific research, however, has established this fact : 

 that their prevalence is often due to climatic influences, — such 

 as the alternations of heat and cold, great and long-continued 

 moisture, excessive droughts, as well as also to the deficiency 

 or bad quality of common articles of food. Wherein lies the 

 essential power of these "climatic influences," whether it con- 

 sists of certain minute particles, inappreciable by the ordinary 

 modes of investigation, originated and set in motion by those 

 influences, or whether by other means, has not yet been de- 

 termined. Here opens a field for scientific discovery which has 

 scarcely been entered on. 



Epidemics, whatever may be their nature, are intimately 

 associated in most minds with contagion ; that is, they are 

 thought to possess contagious properties upon which their 

 prevalence depends. By contagious properties we under- 

 stand the spread of a disease from one individual to another by 

 means of a poison conveyed in a distinct form, as by the secre- 

 tions of the mouth or nose, or in an imperceptible form, as by the 

 exhalations from the lungs or skin. Now, while it is true that 

 epidemics of well-known contagious diseases, as of small-pox, 

 for example, not unfrequently prevail, it is by no means neces- 

 sary, nor is it true, that any or cA^ery epidemic, of whatever 

 nature, should be contagious. Their origin, their sudden 



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