4 THE LUNG PLAGUE OF CATTLE. 



owed its origin and diffusion to a specific-disease poison. We much 

 prefer, and throughout this report have freely used, the appropriate 

 term, lung plague, rather than pleuro-pneumonia, mainly because the latter 

 is already applied to a simple inflammatory affection of the lungs and 

 their covering, without a suspicion of that contagion which is the es- 

 sential element of this disease. The effect of the term pleuro-pneumonia 

 on the average medical mind may be inferred from the fact that in the 

 New York legislature a bill providing for the extinction of the lung 

 plague was defeated through the confident assertions of a medical 

 member of the house that there was not, and could not be, such a thing 

 as a contagious pleuro-pneumonia. No one thinks of calling small-pox 

 ringicorn, or scabies inflammation of the skin, typhoid fever inflammation 

 of the bowels, hydrophobia inflammation of the brain, scarlet fever inflam- 

 mation of the throat, HOT pulmonary consumption inflammation of the lungs. 

 Yet, it would be no more absurd and misleading to call these simple in- 

 flammations of the organs named than to call the contagious lung dis- 

 ease of cattle pleuro-pneumonia. Not being a simple inflammation, but 

 really a specific fever, it ought to be known by a specific name, and we 

 have adopted the term lung plague, already in use, as one well calcu- 

 lated to set forth its essentially pestilential character. 



HISTOBY OF LUNG PLAGUE, AS SHOWING ITS PBOPAGA- 

 TION BY CONTAGION ONLY. 



The same excuse advanced in extenuation of the above reference to 

 historic names will apply to the following presentation of important 

 facts in the history of this affection. The ultimate source of the conta- 

 gion of lung plague We do not know. Up to the present time this has suc- 

 cessfully eluded all investigation. Like small -pox, measles, the plague, 

 &c., this affection is only known as it is transmitted by its own contagious 

 products. If the sanitarian of to-day meets with a case of small-pox, 

 or of lung plague, he at once inquires after some pre-existing case of 

 the same kind, from, which this has been derived, and with the same 

 confidence with which he would, on finding a young animal, inquire after 

 its sire or dam. All historic records of lung plague betray its continu- 

 ous existence in different parts of Europe, where it has prevailed from 

 time immemorial, and show further that the invasion of a new country by 

 the pestilence has ever been but the sequel of the transit of cattle from 

 an infected region, either in the commissariat parks of a belligerent 

 army or in the channels of an opening commerce. Whatever, therefore, 

 may have been the conditions of the original generation of the lungplague 

 virus, whether it was a primary creation at the foundation of the world, 

 or whether it has been the product of an evolution under peculiar modi- 

 fying circumstances, this much can be confidently affirmed, that in 

 Western Europe and in the Western and Southern Hemispheres its 

 appearance can be traced in every case to the introduction of diseased 

 cattle or their products. 



ANCIENT HISTORY OF LUNG PLAGUE. 



The early history of the lung plague of cattle cannot be followed with 

 that certainty which characterizes the records of Eussian cattle plague, 

 foot and mouth disease, sheep-pox, &c., which develop sooner after the 

 system has taken in the infection. The average period of incubation 

 or latency of the poison is, for foot and mouth disease two days, for 



