Contagious Pleuro-Pneumonia of the Ox. 4G9' 



ordinary kind. Inoculation is not attended with constitutional 

 disturbance except in cases where the local disease is excessive. 



Numerous carefully conducted observations have established 

 the fact that the ordinary results of successful inoculation are 

 purely local. Science, in short, offers no evidence in favour of 

 inoculation as a preventive of pleuro-pneumonia. This conclu- 

 sion is practically accepted by all who are most enthusiastic in 

 favour of the operation. Experience is the ground on which they 

 rest their claims, and it is perfectly reasonable that on this ground 

 only the efficacy of the practice shall be affirmed or denied. 



At first, however, it is necessary to remark on a peculiar 

 character of contagious lung disease, the existence of which, 

 renders it at times extremely difficult to decide whether the pro- 

 gress of the malady is cut short by the operation of ordinary 

 preventive measures, or by the protective action of inoculation ;, 

 and this doubt can only be resolved by the aid of experiments, 

 on an extensive scale. 



It is well known, and every year adds to the number of instances 

 of the fact, that an outbreak of pleuro-pneumonia in a herd is 

 sometimes arrested after the loss of a few animals, even when 

 nothing has been done beyond removing the sick beasts as soon 

 as they are observed to be ill, and using ordinary care in the 

 treatment of the rest of the herd. 



Further, it is well known that inoculated animals are liable to 

 become the subjects of a natural attack of pleuro-pneumonia, and 

 that the disease in them is not less virulent than it is in uninocu- 

 lated cattle. These propositions are illustrated so perfectly by 

 two instances of outbreaks of pleuro-pneumonia in different parts 

 of the country, that it is worth while to refer to the details of 

 each case. 



The first outbreak occurred in the summer of 1871 among; 

 some dairy cows, Alderneys, on the estate of the late Marquis of 

 Camden, near Tunbridge. The herd consisted of twenty-two cows,, 

 which were kept together in pastures near the homestead, whence 

 they were driven twice daily to a large shed to be fed and milked.. 

 Four Irish oxen were also at the same time driven to the shed to 

 be fed. These oxen were subsequently slaughtered on account, 

 of pleuro-pneumonia, and there is no doubt that they com- 

 municated the disease to the Alderney cows with which they 

 were brought in contact during milking time. On the occasion 

 of my first visit I ascertained that all the Irish cattle, when 

 slaughtered, were found to be affected with pleuro-pneumonia.. 

 Of the Alderneys one had died, and one was suffering from 

 the affection. The disease had also extended to some calves,, 

 which need not be further noticed, as they were all infected when 

 I examined them, and were shortly afterwards slaughtered and. 



