22 The Lung Plague of Cattle. 



of the disease lie so long dormant in the system. A 

 beast purchased in October passes a bad winter, and dies 

 in February, after having infected several others. She 

 lias had a long period of incubation, and when thef disease 

 supervenes actively, she has passed through a chronic 

 form of illness, so that when others sicken people fail 

 to connect the new cases with the infected purchase. 

 Then, again, in an ordinary herd of 10 or 20 head, the 

 deaths do not foUow in rapid succession, but at intervals 

 of a fortnight, a month, or even more, and those unac- 

 quainted with the nature of the disease suppose that it 

 cannot be infectious, or all would be prostrated at once. 

 Pertinent to this point are the following remarks ex- 

 tracted from a letter of the author which appeared in the 

 New York Tribune, March 12th, 1879 : 



" THE DISEASE NEVEE AEISES IN THIS COUNTEY BUT AS THE 

 EESULT OF CONTAGION. 



" That this malady is contagious is shown every day 

 in the course of our work. Wherever we find it existing 

 in a herd we obtain a history of a recent purchase, or of 

 some other form of exposure by which the herd has 

 been infected. To give illustrations would be to record 

 the whole history of our course in stamping it out so 

 far. But this is not enough. The disease is not only 

 contagious, but in this country it is only propagated by 

 contagion. Throughout the immemorial ages of this, 

 the oldest of continents, the herds of buffalos roaming 

 over its plains never contracted this affection. Yet buf 

 falos are susceptible to this disease, as well as our domes- 

 ticated cattle. And if the buffalos on the unfenced plains 

 had once developed the malady it would have remained 

 as a permanent plague, as it has throughout all historic 

 periods in the open steppes of Eastern Europe and Asia, 

 since 1854 in Southern Africa, and since 1859 in the wide 

 stock ranges of Australia. During the long period that 

 has elapsed since the colonization of America the cattle 

 have been subjected to all the conditions of life that have 

 beset them since ; but until 1843, when an infected cow 



