PROTECTIVE PROCESSES IN GLANDERS. 627 



toward the lymph glands. The nodules, and also 

 the cords, commonly undergo softening, and ab- 

 scesses form and rupture through the skin. Nod- 

 ules similar to those in the skin develop in various 

 organs of the body; in the nose they break down 

 and constitute ulcers. In chronic infections the 

 lesions are of the same nature, although they evolve 

 more slowly and tend to remain limited to particu- 

 lar regions. Nasal, pharyngeal, tracheal or pulmon- 

 ary glanders are forms of the disease which are en- 

 countered in the horse. Connective tissue develop- 

 ment is more marked in chronic than in acute 

 glanders, although the peculiar liquefaction, sup- 

 puration and ulceration of the lesions occur in the 

 former as well as in the latter. Moderate leucocy- 

 tosis is found in the blood (12000-14000). 



The nature of the pathologic changes found in Protective 



,,.,,, . i Processes. 



glanders, the frequent chronic and the progressive 

 course of the disease, and the fact that infection 

 does not confer distinct immunity, are conditions 

 which ally glanders closely to tuberculosis, 

 pseudo-tuberculosis and leprosy. The essential 

 lesion is the "infectious granuloma," and it is prob- 

 able that the new connective tissue which is formed 

 is to no small extent a factor in limiting the exten- 

 sion of the infection. Nodules of glanders fre- 

 quently are isolated by the surrounding reaction, 

 the centers caseate and the contents eventually are 

 discharged through the skin ; cicatrization and 

 healing in many lesions follow evacuation. Phago- 

 cytosis of the bacilli by the epithelioid cells and leu- 

 cocytes in the nodules is said to be rather extensive. 

 Agglutination of glanders bacilli takes place in 

 high dilution with the serum of horses affected 

 with glanders. An agglutination with serum in 



