EPITOME OF EVIDENCE ON PLEURO-PNEUMONIA. 271 



and then at intervals of a week or so. The dair^Tnen in Glas- 

 gow come to me readily to report outbreaks of disease. I am 

 generally able to trace back the animal that communicates the 

 disease. The next outbreak was about five years after that. I 

 had to buy animals, as at that time I only bred a few. This 

 animal was also from the Glasgow Cattle Market. It was in 

 my possession about the same time as the animal in the first 

 outbreak. It is a very fair average time, about six weeks, after 

 a diseased animal enters into a sound stock before the other 

 animals show indications of pleuro-pneumonia. If more than 

 six months had elapsed before the disease broke out, I would 

 have considered that pleuro-pneumonia had been encysted in 

 such a case. The period when an animal with an encysted 

 portion of lung may give off infection is uncertain. As soon 

 as the capsule breaks up, the cow becomes a source of infection. 

 On the advent of lung disease in a dairy I always put it in this 

 way to our dairymen in Glasgow. The best plan is to kill the 

 animal, and the earlier you kill it it will be all the better, be- 

 cause, if it be contagious pleuro-pneumonia, the carcass will be 

 fit for human food, and if you allow it to go on it will be unfit. 

 We kill the animal there and then, and if it is pleuro-pneu- 

 monia the party is compensated. On the other hand, if it is 

 any other disease, the party disposes of it on his own account, 

 and does not lose much money. In ordering the first animal in 

 a herd to be slaughtered we require to exercise great care, 

 because the symptoms of simple pleuro and contagious pleuro 

 are so very like one another. Contagious pleuro is a specific 

 disease, in which you have structural changes taking place in 

 the lung, which are almost identical with the changes that are 

 connected with simple pleuro. The symptoms of non-contagious 

 " pleuro " and contagious " pleuro " being so much alike in the 

 living subject, I would say that no man is justified in saying 

 that that is not a case of simple pleuro. Without any history of 

 the animal, suppose you have one labouring under simple, and 

 the other labouring under contagious pleuro — about the same 

 number of days standing, and I defy any one to say whether it 

 is simple or contagious pleuro. To say decidedly that an animal 

 while alive is labouring under contagious pleuro-pneumonia, and 

 not simple pneumonia, is, in my opinion, more than any man is 

 able to do. Whenever you allow me to kill the animal, I will be 

 in a position to do so. The difference on post-mortem examina- 

 tion to a party who has had a large experience, is a difference 

 able to be made out. Contagious pleuro-pneumonia is a disease 

 of slow progress. The changes produced on the lungs of the 

 animal affected with contagious pleuro are slow changes ; whereas, 

 when affected with simple pleuro, there are acute changes. An 

 experienced eye can see the difference. In contagious pleuro 



