Glanders. 241 



sometimes fails in advanced cases of glanders, but in such a case 

 other symptoms are usually diagnostic so that mallein is superflu- 

 ous and should not be misleading. The greatest care should be 

 taken to prevent infection from the syringe, nozzle, skin, hands, 

 etc., as other infections may give rise to local swelling and hyper- 

 thermia (see tuberculin test). If a first test leave^ the matter in 

 doubt, the animal should be secluded and tested again in a month 

 (some prefer 3 months). 



Pathological Anatomy. The colonization of the bacillus mallei 

 in a tissue usually determines a concentration and multiplication 

 of leucocytes, so as to form rounded nests of small lymphoid cells 

 in a scanty fibrous network. These may be miliary or by aggre- 

 gation they form masses the size of a pea or larger, which bear a 

 close resemblance to the neoplasms of tubercolosis. As in tuber- 

 cle the central cells of the group, degenerate, forming a granular 

 fatty debris, and constituting an ulcer or abscess. In certain 

 cases with a proliferation of fibrous tissue a cicatricial material is 

 developed. Another characteristic lesion is the occurrence of 

 hyperplasia in the walls of the lymph vessels so as to constitute 

 firm tender cords, and the infiltration of the adjacent lymphatic 

 plexus. 



In the nasal mucosa the bacilli form prolific colonies at different 

 points of the membrane and submucosa with the active production 

 of lymphoid cells, followed by granular fatty degeneration and 

 ulceration. Hence may be found different lesions representing 

 the different stages. First there may be miliary deposits with 

 clear contents and standing out like grains of sand. Then there 

 are the larger pea-like uoJules with congested vessels and minute 

 haemorrhages, but made up largely of the nests of lymphoid cells. 

 These may bear on the surface a distinct blood extravasation, or 

 the epithelium may be raised from the corium layer by a liquid 

 exudation. The more advanced nodules show the centre light 

 colored, grayish or yellowish with a distinct granular degenera- 

 tion of the cells. Later still the degeneration involves the super- 

 ficial layers and epithelium and an open ulcer is formed with a 

 strong tendency to extend in depth and width. The formation 

 and degeneration of numerous foci of cell proliferation gives the 

 ulcer a very uneven outline. The continuous growth of fresh 

 centres of proliferation may cause marked elevations between the 

 16 



