52 INFLUENZA. 



was there a more or less pronounced oiitbrcalc of the con- 

 tapfious lung fever of cattle. 



The imported horses to which I have referred come from a 

 distance, collected at fairs or markets, or from other dealers ; 

 they are, on their arrival at the stables of the dealers, often 

 delayed in their distribution over the district b}^ the appearance 

 of influenza fever, and, when not disposed of before its out- 

 break, are rarely retained until perfectly recovered, but sold as 

 early as possible. The advent of these strange horses amongst 

 those of the district is followed by the occurrence of the fever 

 in very many of the stables to which they have been consigned, 

 and it rarely exhausts itself until the greater number have 

 shown more or less of the disease. These phenomena are of 

 regular occurrence, and upon their recurrence horse-keepers 

 can with tolerable certainty calculate. 



The evidence which I have been able to collect, on the occa- 

 sion of several special invasions of influenza, j)oints in the 

 same direction. Although not so conclusive as that to which 

 I have alluded, the facts connected with its dissemination in 

 those instances were — (1) That the disease showed itself earher 

 at those places where animals were brought largely into con- 

 tact with others, centres of local trade, than at other points 

 where these conditions were reversed. (2) That from these 

 centres of contact it could be traced as propagating itself 

 to more isolated localities. These facts seem to point to the 

 presence in the diseased animal of a specific poison or con- 

 tagium, which is capable of transference to other and healthy 

 animals ; and that, when received by them, is capable in them 

 of producing a like diseased condition to that existing in the 

 animal from which this infecting agent proceeded ; also that 

 in the contaminated animal it is further capable of increase or 

 augmentation, and of transference again to another suitable 

 host. 



Of the causes which operate in the production of epizootic 

 influenza, in so far as preparing a suitable soil or habitat upon 

 which the morbific influences may operate, we know some- 

 thing — causes which seem to have a determining influence in 

 the appearance of all contagious or z}rmotic diseases. These 

 have been noticed as intrinsic and extrinsic, debilitating and 

 degrading forces. Of the exact nature of direct or epizootic 



