60 THE LTJ1NG PLAGUE OF CATTLE. 



better alternative the entire extinction of the disease and there can 

 be no hesitation in the choice. 



For eradicating the lung plague inoculation may be advocated in the 

 case of insular or other perfectly secluded localities where the contagion 

 is already widely diffused and still spreading. It must be made on every 

 bovine animal in such place, and repeated on such as do not take the 

 first time. A close inspection must be kept up on the whole ; the sick, 

 whether chronic or acute cases, must be killed, and all calves born in 

 the herd miist be at once inoculated or destroyed. If calves are con- 

 tinually being born in the herd, it will be necessary to destroy them for 

 some time, as their continuous inoculation entails a perpetuation of the 

 poison. 



PRESENT LIMITS OF LUNG PLAGUE IN THE UNITED 



STATES. 



In pursuance of our instructions "to investigate all cases of the dis- 

 ease known as pleuro-pneumouia in neat cattle which shall be reported 

 to you, especially along the dividing line between the United States and 

 the Dominion of Canada, and along the lines of transportation from all 

 parts of the United States to ports from which cattle are exported, and 

 to perform such other duties as may from time to time be prescribed by 

 the Secretary with reference to said disease, to the end that cattle 

 shipped from ports of the United States to foreign ports may be known 

 and certified to be free from the disease in question," we have felt it 

 less incumbent on us as yet to make any special investigations in the 

 eastern areas known to be infected, and the limits of which are already 

 fairly well defined, than to determine the question as to whether the 

 disease had already spread beyond these areas and invaded New Eng- 

 land or the country west of the Alleghany Mountains. 



To this end Dr. Thayer has made extended investigations in New 

 England, and Professor Law'in New York, and both in the great cattle 

 centers of Chicago and Peoria ; while the other great centers of the live- 

 stock trade have been subjected to rigid scrutiny by veterinarians de- 

 puted to the different points. In the same way we have investigated 

 all cases of supposed contagious lung disease of cattle reported to us, 

 and to-day we report a complete failure to find lung plague anywhere 

 west of the Alleghany Mountain range or in the States of New England. 



The conclusiveness of this statement will be better understood when 

 we add that in most of our Western cities where cattle markets are held, 

 the conditions for the preservation of this plague are at least equally 

 favorable with those found around our infected Eastern cities, where this 

 palgue has been maintained uninterruptedly for over thirty years. Thus, 

 in all, the supplies of city dairy cows are drawn from the adjacent stock- 

 yards, where cattle of all kinds and from all different points mix and 

 succeed each other in the same inclosures. If, therefore, diseased cattle 

 had passed through these yards the contagion must sooner or later have 

 reached the city dairies, where the infected buildings and the frequent 

 changes of stock, to keep up the milk supply, would have preserved it 

 without fail. So with the herds in the distillery and other feeding- 

 stables. These are supplied from the public stock-yards, and would 

 early receive infection were that present in these yards ; and the infec- 

 tion once received into these stables it must have been perpetuated, as 

 it is in distillery stables in the East and in all parts of the world where 

 the infection exists. 



