PATHOLOGY. 221 



fact that the bronchial glands at the bifurcation of the trachea 

 are always much more severely affected than any of the other 

 lymphatic glands argues against the theory that epidemic pneu- 

 monic plague is primarily a septicremic disease, and that the 

 lungs are infected secondarily from the blood. Moreover, in the 

 earliest stage of the disease, the blood may be free from plague 

 bacilli.'-' The conditions observed in the trachea and bronchi in 

 epidemic pneumonic plague, together with the character of the 

 pulmonary exudate, is pathognomonic of this condition. From 

 the appearance of the mucous membranes of the throat, larynx, 

 and trachea, a diagnosis of pneumonic plague may sometimes 

 be suggested. The tonsils may become secondarily infected in 

 pneumonic plague, just as other lymphatic glands — for example, 

 the bronchial ones — become so infected. However, in pneumonic 

 plague, death occurs before any very marked macroscopic changes 

 occur in the tonsils. There is no doubt also that the tonsils 

 may become primarily infected in epidemics of pneumonic plague, 

 just as has occurred in sporadic cases during epidemics of bu- 

 bonic plague. This, however, is not the common channel of 

 primary infection, and in such cases involvement of the lym- 

 phatic glands of the neck occurs early in the course of the disease. 

 The fact that the oesophagus was found to be normal in every 

 case examined and that the intestines showed only slight lesions 

 constitutes another argument against the idea of the occurrence 

 of primary intestinal plague infection in man, since in many 

 of the pneumonic cases plague bacilli must have been repeatedly 

 swallowed in the bronchial secretions and in the saliva. 



" See p. 202 of this report. 



