IG SMALL-POX IN SlIKKP. 



must not lose si^rlit of the circumstance, that very 

 many infectious diseases assume an endemic type, 

 wliilst others which are spread over a vast extent of 

 country are often observed to take a particular direc- 

 tion. There are, however, diseases of this kind that 

 appear to be guided by no determined rules, breaking 

 out again and again in the same neighbourhood ; but 

 even here we may suppose, with good reason, that the 

 deleterious atmosphere floats, as it were, in nebula, and 

 is driven hither and thither by the currents, sacrificing 

 fresh subjects placed in the course of its passage. 



Although, then, "one swallow does not make a sum- 

 mer," yet one positive proof of the communication of 

 disease from animal to animal should render us very 

 cautious, and much influence the opinions we may give 

 on so important a point. 



Judo-ing from our present experience and observa- 

 tion, as well as from the facts related to us, we have 

 every reason to fear that Variola Ovina is both conta- 

 gious and infectious. 



