EPITOME OF EVIDENCE ON PLEURO-PNEUMONIA. 251 



of those marts are open to the air much more than close con- 

 fined buildings. We have had outbreaks that have made me 

 conclude that the disease can be carried in currents of air. 

 I should consider it dangerous to have infected animals 

 at a distance of 200 yards. I have known of infection being 

 carried over a field of 200 yards in width ; that is quite a 

 common thing. When an outbreak occurs, you should declare 

 an area to be kept free around the place where the disease 

 has broken out. In some cases the owners of stock would only 

 have a certain number inoculated, and the result was that these 

 animals were saved and the others died. I have inoculated 

 lots of animals, and I have brought in fresh ones, and put them 

 alongside of the inoculated ones without bad results. I believe 

 that inoculation gives absolute immunity during the life of a 

 beast. I have inoculated calves and other young stock, and 

 these have grown up, and while pleuro-pneumonia existed 

 around they remained the only free animals. My experience 

 of my system shows that there is certain immunity, and I have 

 not met a case showing the reverse. That is a matter that 

 the Society should take up, and you will get most valuable 

 information on the point. I would suggest that the Society 

 should take up and investigate whether it could be shown that 

 in the case of animals that have passed through inoculation, and 

 declared free of disease, any of them could communicate the 

 disease to others. We know that inoculated animals healthy at 

 the time of the inoculation cannot produce the disease in other 

 animals. The only point is whether those that have escaped 

 observation, and supposed to be slight cases, can communicate the 

 disease ? I say they cannot. The question is, can the disease 

 exist or lie latent after successful inoculation ; and if so, for how 

 long ? I think that is a good thing to investigate. It is a 

 thing deserving of investigation whether there might be really 

 any danger to healthy stock if inoculated tails came into contact 

 with them. Then, again, will animals, themselves healthy and 

 inoculated, communicate disease to animals healthy but not 

 inoculated ? These are two of the most important points as 

 affecting our export trade. 



Mr Rutherford, F.R.C.V.S., Edinburgh, called in, and 



re-examined. 



An animal will not accept inoculation twice ; that is my 

 uniform experience. In the limited area cases, I think the 

 lesion becomes altered. The introduction of the virus on 

 the outside modifies the tendency to lung lesion. During 

 years and years' experience, I have inoculated thousands of 



