690 Glanders. 



of infection and, further, the fact that normally expired air 

 contains no glanders bacilli and that direct transmission of 

 the virus from animal to animal through the act of coughing 

 or snorting is only exceptional, one is necessarily forced to 

 the conclusion that aerogenic infection plays a very secondary 

 role in the development of glanders. 



As a rule the disease is a result of the ingestion of food 

 or water contaminated with the secretions (glanders bacilli) 

 of infected horses. The bacilli enter the lymph vessels of the 

 intestinal walls through the intact mucous membrane and then 

 pass into the mesenteric lymph vessels; during this process, 

 although it is undoubtedly a rare occurrence, they may give 

 rise to inflammatory changes in the follicles of the intestinal 

 mucous membrane as well as in the mesenteric glands. Follow- 

 ing the course of the lymph stream they enter the thoracic duct 

 and are discharged into the blood with the contents of the 

 latter. This results in a general blood infection, attended with 

 febrile elevation of body temperature, inflammatory swelling 

 of the lymph glands (including those of the intermaxillary 

 space), and of the nasal mucous membranes, as the first stage 

 of the disease. A part of the bacilli which circulate in the blood 

 are deposited in the capillaries of the lungs, the organ pre- 

 eminently susceptible to infection, while others may lodge in 

 other organs — ^thus, also in the nasal mucous membrane — and 

 exert their pathogenic action; in part, however, they are evi- 

 dently destroyed in the blood and in the lymph glands. How- 

 ever, as Lothes had already noted in his practical observations, 

 the possibility exists that the virus may enter the lymphatics 

 of the neck jand thorax directly from the pharyngeal region. 



After lodging in the small blood and lymph vessels the bacilli of glanders 

 give rise to a proliferation of the surrounding endothelial cells and of the extra- 

 vascular connective tissue cells which results in the formation of nodules composed 

 of epithelioid cells; subsequently white blood cells pass from the periphery and 

 lodge between the cells of the nodules, as a result of which the latter become 

 softer in consistency and finally degenerate into a purulent mass which contains, in 

 addition to well preserved pus corpuscles, large masses of degenerated cells and 

 cell- and tissue- detritus (Baumgarten). The nodule which is at first hyaline, 

 assumes a white or yellowish-white color, while the surrounding hyperemie tissue 

 which is infiltrated with small round cells forms a red area. As the nodules enlargis 

 and the cellular elements rapidly break down larger foci composed of detritus and 

 pus cells and surrounded by a red area are formed. If the nodule developed in the 

 mucous membrane or the skin, the resulting superficial necrosis is followed by grad- 

 ually progressive ulceration. 



When only a few bacilli are present or when the tissues possess unusual resist- 

 ance the process may be interrupted in its initial stage, or it may not be inter- 

 rupted until considerable connective tissue has accumulated around the glanderous 

 foci; following either condition definite recovery may result, the ulcers cicatrizing, 

 the purulent centers becoming dry, and, in exceptional cases, calcifying. 



In other cases the bacilli find their way into the surrounding tissues through 

 the lymph channels, the lymph vessels of the subcutis forming thick, knotty strands 

 and the regional lymphatic glands becoming enlarged. 



If, as a result of hematogenic infection, the bacilli have 

 accumulated in large masses in the capillaries, they may cause 

 emboli and hemorrhages and edematous infiltration of the sur- 



