THE SPLENIC FEVEK. 119 



of ticks and the severity of the disorder. The malady has been quite as malignant where 

 few or no ticks occurred. 



3d. We have been asked to watch for the irritating parasites in the stomach and 

 intestines, and it was believed that they acted mechanically; but wo have never seen a 

 tick during any stage of its development in the alimentary canal. 



4th. The tick is not confined to Gulf-coast cattle, which we know communicate this 

 disease; but it is met with in various parts of the States where cattle are reared that 

 never cause splenic fever. Why should the ticks not communicate the malady from west 

 ern cattle to other cattle, if they can induce it by crawling from the Texan to western 

 stock? Many erroneous views as to the origin and propagation of the Texan fever may 

 be set at rest by showing what it is not; and for this reason I shall proceed to discuss 

 the analogies and differences between splenic fever and other disorders afflicting cattle, 

 and even the human species. 



THE NATURE OP SPLENIC FEVER. 



The history of splenic fever would seem to indicate its complete isolation from every 

 disease, and especially every form of plague hitherto described. But a careful study of 

 its progress and development, with the light afforded by a knowledge of other cattle dis 

 eases, enables us to demonstrate points of great resemblance, and indeed of identity with 

 maladies which annually recur in various parts of the world. It is, moreover, important, 

 in a practical point of view, to show how it differs from maladies which spread from 

 country to country, and from the east westward, devastating broad tracts of land, and 

 calling for the most decisive and energetic means for their suppression. 



Splenic fever is not an epizootic, properly so called. It is not propagated through 

 time and space by contagion. The true plague of animals, or epizootics, such as the Rus 

 sian murrain or rinderpest, the lung plague or contagious pleuropneumonia of cattle, the 

 foot and the mouth diseases of all warm-blooded animals, variolous fevers, hydrophobia, 

 and the like, spread by direct or indirect transference of an animal poison, a virus, from sick 

 to healthy animals; and in the Old World the sick, as a rule, indicate, by very manifest 

 outward symptoms, the disease under which they are laboring. The poisons take effect 

 without regard to seasons, and are alike developed in the systems of sick animals. It is not 

 contact between Texan and southern or western cattle that induces the malady; and, so 

 far as recorded observations and my own inquiries at present extend, the animals contami 

 nated by feeding on Texan trails have not in a single instance propagated the disease to 

 other animals. Indeed, I have not met with one instance where sucking calves have 

 caught the affection from their dams, or from other cows which they have been made to 

 suck. Many cases have come under my observation of cattle in Illinois, Indiana, and 

 elsewhere, coming in contact with Texan cattle through a fence, by drinking of the same 

 water, and even being housed in sheds with sick natives, and yet escaping the disease. 

 We must, therefore, distinguish it from the contagious maladies alluded to, and refer it to 

 another group. 



Splenic fever is an enzootic. It originates in various parts of the Gulf States. 

 Florida cattle driven north are as dangerous as Texans, deriving the same deleterious 

 properties from the soil on which they are reared, and in all probability the vegetation 

 on which they feed. In the South, splenic fever is distinctly indigenous, and, so far as 



