The One Known Cause. 13 



Connecticut in the New. To the same purpose speaks 

 the immunity of Spain and Portugal, guarded by their 

 peninsular position, the bold walls of the Pyrenees, and 

 the entire absence of cattle-traffic ; of 'parts of Brittany 

 and Normandy, of the Channel Islands, and of the High- 

 lands of Scotland, that breed their own stock and nevei 

 import. To the same end speaks also the absence of the 

 disease in our Western States, and in Massachusetts 

 since 1864, when she crushed out the imported plague. 

 The disease, then, is only known as a contagious malady, 

 and the unhygienic conditions above referred to only 

 favor its propagation so far as they favor the preservation 

 of the morbid germ already in existence, or weaken the 

 animal vitality and power of resistance and lay the sub- 

 ject more open to disease. Faulty surroundings will 

 greatly favor the dissemination of the disease, but have 

 never been known to generate it. The primary origin of 

 its germ is as great a mystery as in the case of small-pox 

 or plague. 



But for some readers this is not enough ; it may be 

 conceded that the true Lung Plague of European cattle 

 is only propagated by contagion, and that in the absence 

 of importations of sick cattle and their products no coun- 

 try need fear an invasion of this disease, and yet doubts 

 and objections of all kinds are raised : 1. Is the present 

 lung disease of cattle in certain of our Eastern States the 

 genuine Lung Plague of Europe ? 2. Conceding that it 

 is the same disease as respects its origin, has it not lost 

 much or all of its virulence in being transplanted to the 

 New World? 3. Allowing that it is at once the Lung 

 Plague of Europe and that its virulence is preserved on 

 tlie American Continent, is it not the case that its infec- 

 tion can only be propagated by the direct contact of the 

 sick with the healthy cattle, while the transmission of the 

 virus through any intervening medium renders it inope- 

 rative ? 

 2 



