122 DEPARTMENT OF AGRICl'LTURE. 



Tlic " tick tlicorv" has acquired quite a renown during the past sum- 

 mer; but a little thought should have satisfied any one of the absurdity 

 of the i(U'a. In the tirst place, ticks are not easily fenced on a ))iece of 

 hind, by a wood ience, as cattle are. A wood fence sufliciently isolates 

 cattle to prevent splenic fever. 



Secondly. We have seen Texan cattle without ticks; and such cattle, 

 and also dead western, quite free from these parasites. There has been 

 no relation whatever between the abundance of ticks and the severity of 

 the disorder. The malady has been quite as malignant where few or no 

 ticks occurred. 



Thirdly. We have been asked to watch for the irritating parasites in 

 the stomach and intestines, as it was believed that they acted mechan- 

 ically ; but we have never seen a tick during any stage of its develop- 

 ment in the alimentary canal. 



Lastly. 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 western 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 1 shall proceed at once to discuss the analogies and differences 

 between splenic fever and other disorders afflicting cattle, and even the 

 human species. 



THE NATUEE OF SPLENIC FEVER. 



The history of splenic fever would seem to indicate its complete isola- 

 tion 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 diseases, enables us to 

 demonstrate points of givat 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 propa- 

 gated through time and space by contagion. The true plague of ani- 

 mals, or e]uz()otics, such as the Russian nuirrain or rinderpest, the lung 

 plague or contagious pleuro-pneumoniaof cattle, the foot and the mouth 

 diseases of all warm-blooded animals, variolas fevers, hydroi)liobia, and 

 the like, spread ]»y direct or indirect transference of an animal poison, a 

 virus, fronj sick to healthy animals; and the sick, as a rule, indicate, by 

 very manifest outward symptonis, in the old world the divsease under 

 which they are laboring. The i)oisons take effect without regard to sea- 

 sons, and are alike developed in the systems of sick animals. It is not 



