58 JOHNKS DISEASE 



mentioned are less frequently found in the intestines 

 than in the lymphatic glands. 



Johne and Frothingham, in their original paper, 

 remarked on the scanty number of typical giant cells 

 compared with the quantity usually found in bovine 

 tuberculosis. The increase in thickness of the gut is 

 thus seen to be due to the infiltration of new cells, 

 which are chiefly of an epithelioid type. In advanced 

 cases, in which very many bacilli are present, the 

 normal tissue may be extremely atrophied, while the 

 fibrous tissue stroma remains with an infiltration of 

 epithelioid cells. In cases in which the submucosa is 

 affected, it is found to be thickened generally, while 

 the muscularis mucosae is always easily distinguish- 

 able. The muscular and serous layers of the organ 

 are normal. 



Various authors, including B. Bang, have stated 

 that there is some necrosis with desquamation of the 

 epithelium. Bang has since pointed out that this is a 

 post-mortem change, and is not seen in sections of 

 fresh gut that have been hardened in a solution of 

 formalin immediately after the animal is killed. 

 Nodules similar to those found in tuberculosis are 

 rare, and it is probable that true caseation is never 

 found in this situation. In at least loo carefully 

 examined sections, Johne and Frothingham were able 

 to find only three sites in which there was any simi- 

 larity to nodules of tubercular disease. These nodules 

 consisted of epithelioid cells and lymphocytes, with 

 one or two giant cells containing bacilli. In this con- 

 nection the possibility of coincident tuberculosis must 

 be remembered. In the large intestine the condition 

 found is more or less similar to that in the small 

 intestine, but the lesions are usually not so far advanced 

 and the number of bacilli present is less. 



