10 JOHNE^S DISEASE 



have been able to recover the bacilli from the deeper 

 layers of the mucous membrane of the intestine ; but 

 the thickening of the bowel in some of these cases 

 was scarcely noticeable, and, indeed, infection could be 

 proved only after a careful microscopic search, or by 

 the cultivation of the bacillus. Yet, of those animals 

 which on post-mortem examination show only slight 

 lesions of Johne's disease, many are thin and in poor 

 condition, being obviously affected by the bacilli or 

 their products. It is reasonable, therefore, to sup- 

 pose that in addition to the cases reported in the 

 Birmingham abattoir, a good many occur which it is 

 not possible to detect in the ordinary course of meat 

 inspection. Besides these well-marked and slight 

 cases, there must be added those animals which die 

 of the disease, or are slaughtered at home as being 

 useless to send to a properly inspected meat market, 

 where, on account of extreme emaciation, they would 

 be condemned. On the other hand, Parker of 

 Newcastle, in answer to an inquiry, states that the 

 condition is very rarely met with in the abattoirs in 

 that city; and he accounts for this by the fact that 

 only very good-class bullocks are slaughtered there. 



In 1910, Riddoch, in inspecting about 2,800 dairy 

 cows kept in the city of Edinburgh, diagnosed three 

 cases by the examination of rectal scrapings ; but he 

 states that slaughterhouse statistics in the city would 

 be of little value, as all the extreme cases would be 

 totally condemned on account of emaciation, the cause 

 of which would not be stated. 



At Belfast the disease seems almost unknown, and 

 at the Dublin abattoir distinctly uncommon. From 

 County Armagh, Thompson writes that he is unaware 

 of the existence of the disease in his district, and 

 though the disease is met with in Limerick, Wallis 



