268 EPITOME OF EVIDEXCE OX PLEURO-PNEUMOXIA. 



tissues with the extravasated blood ; it causes at that point 

 lesions identical with the original lesions in the tail, and they 

 extend in the same way as in the tail, so that a blow is 

 dangerous to a cow in any part of the body. My strong 

 point is this, that you never know in any byre where you are 

 inoculating, whether there is not an " old stager," as we call 

 them, or not ; and that inoculation does not reveal its presence. 

 I do not want you to suppose that I am an opponent of inocu- 

 lation ; up to a certain point I advocate it. I have inoculated 

 animals in two bjTCs with the same lymph and in the same 

 manner. In the one case the lesions were so serious that we 

 lost several cattle with them. The local conditions have a 

 great deal to do with the results of inoculation. I cannot 

 give you any better proof of this than that afforded by the 

 fact that some cows inoculated with the same instruments 

 and with the same virus, took very severely, and the others not 

 at all ; and those that took it severely had the proper pleuro- 

 pneumonia lesion. There was no septicaemia. Inoculation is a 

 local means of suppression ; but if you are to send the con- 

 taminated remnant out, you do not know whether there is, or 

 is not, an old case amongst them to disseminate the disease. 

 So long as we get a piece of dead lung encysted it probably 

 does no harm, but when it becomes connected with a bronchial 

 tube, the infection is spread by the breath, and I was the 

 first to draw attention to this fact. If you have a cow with 

 acute pi euro-pneumonia, that cow is more likely to spread 

 the disease more rapidly than would a cow with a chronic 

 lesion. The one is giving off material from the mucous mem- 

 brane of the bronchial tubes, whereas the other is giving 

 it off from the small patches. I have one case here to which 

 I wish to direct your attention connected with G.'s byre, where 

 there was a cow of which I was suspicious. She was ino- 

 culated by B., and she remained in the byre after it was 

 declared free, and four cows were brought in subsequently — 

 two Danish cows and two from Lanarkshire. When we killed 

 the suspicious cow, we found an old pleuro lesion, and the four 

 fresh cows all contracted the disease from her. Inoculation is of 

 the highest possible value in bjTes where the animals are to 

 be removed for slaughter, but not where they are to be sent 

 through the country to mix up with cattle in other places. 

 Unless inoculation was made compulsory all over the country 

 in both old and young animals and the animals themselves 

 isolated afterwards, you would not get rid of it. I would cer- 

 tainly include half a mile to a mile in an infected area. I 

 would make it compulsory that animals Avithin that area 

 should be inoculated — say within half-a-mile. I do not think it 

 equally important to inoculate feeding beasts, because they are 



