THE LUXG PLAGUE. 55 



healthy with inoculated animals may lead to extensions of the infection, and that 

 the foci whence the disease spreads are always on the increase. Such objections can 

 not weigh against the inoculation for the lung plague, as the inoculated malady is not com 

 municated except by reinoculation. My observations on this point are very numerous, and 

 I do not know of a single instance recorded, during the seventeen years that inoculation 

 has been extensively practiced, in which contagion from inoculated animals has been 

 witnessed. 



Another objection which has led, of late years, to the practice being checked among 

 the cow-feeders of Brooklyn, is the sloughing of the tail and the animals splashing blood 

 and matter from their sore tails into the milk-cans. All this arises from the operation 

 being performed by persons who know nothing of the precautions to be used, and especially 

 of the proper selection and preservation of the virus. Accidents will happen; but out of 

 nearly two thousand inoculations I have had a loss of less than one per cent, by death, and 

 under five per cent, of the tails have lost their tips. This includes my earlier trials, and 

 the results would be more favorable if I excluded them from my calculations. 



PRECAUTIONS. 



The prevention of pleuropneumonia by inoculation demands, therefore, special atten 

 tion, first, to the condition of herds operated on; second, selection of proper virus; third, 

 the preservation of that virus from decomposition ; fourth, the proper performance of the 

 operation. 



First. As to the condition of stock, it may be said that at any season and under any 

 system of management, whether cattle are being grazed, stall-fed, used for breeding pur 

 poses, or fattening for the butcher s stall, inoculation may be resorted to. It should be 

 practiced as soon as there is reason to believe a herd has been in danger of infection or 

 actually infected. The first case of well-marked lung plague on a farm or in a dairy shed 

 should be the starting point for careful isolation, and the inoculation of all apparently 

 healthy animals. The disease rarely manifests all its virulence until the third month after 

 the introduction of a sick animal among a lot of cattle, but the longer the inoculation is 

 delayed the more likely is it that the operation will be performed on animals during the 

 stage of invasion of the natural disease, and the result is a loss which is sometimes ascribed 

 to the inefficacy of the preventive. In cities where the lung plague has been rife for any 

 length of time, and it is necessary to make frequent purchases, although a great deal in 

 the way of prevention may be effected by judicious purchases of animals in healthy dis 

 tricts, it is best to resort regularly to inoculation. Dairymen should strive to buy more 

 cows at a time, and at regular intervals, instead of picking up a chance bargain or making 

 it a rule to go to the market weekly, as has been the custom in both England and 

 America. It matters not if the cow is about to calve or has just calved; nothing should 

 induce the dairyman or the farmer in an infected district .to run a risk. It is desirable to 

 keep animals clean and well littered on straw or sawdust, to prevent the tails that have 

 been operated on from coming in contact with excrement and urine, which may poison 

 the wound with decomposing matter. 



Second. The selection of proper virus should be intrusted to veterinarians, who 

 can detect the various stages of the disease. It is during the first stage of a 

 mild case that the interlobular tissue of the lung is found distended with a yellow 



