362 A MANUAL OF BACTERIOLOGY 



the alveolar walls undergo necrosis, and the leucocytes 

 necrose and disintegrate, but their chromatin persists as 

 rounded fragments which retain their affinity for nuclear 

 stains (chromatotaxis). The nodule may become sur- 

 rounded with a thin layer of fibrous tissue, between which 

 and the necrotic central area a zone of endothelioid cells 

 with giant-cells may be present (Plate VIII, b). 



The lesions of farcy are at the onset histologically 

 identical with the glanders nodule, but by the progressive 

 liquefaction of the tissues actual abscesses form. 



The lesions set up in an inoculated guinea-pig are very 

 characteristic, and can be used for diagnostic purposes. 

 With a very virulent culture, such as can be obtained by 

 several passages through a susceptible animal, a guinea-pig 

 may die in four or five days, and the post-mortem lesions 

 are slight, consisting of some caseation at the seat of 

 inoculation and slightly enlarged spleen, which contains a 

 few small yellowish nodules resembling miliary tubercles. 

 The material from human cases as a rule seems more 

 virulent than that from the horse, and death of the 

 guinea-pig often ensues a few days after inoculation. 



The culture or material from a glandered horse does not 

 usually produce death of a guinea-pig until a lapse of 

 two or three weeks. A male guinea-pig being chosen, the 

 changes observed are caseation followed by ulceration 

 at the seat of inoculation, when this is done subcu- 

 taneously, and great enlargement of the testicles ; on 

 cutting into these they are found to be partially or almost 

 entirely converted into a pasty caseous material, while 

 the skin covering them is so adherent that it can only be 

 detached by cutting, and the spleen is very much enlarged 

 and studded with small yellowish nodules. In a female 

 guinea-pig the ovaries are attacked. These appearances 

 are of importance in the diagnosis of the disease. The 

 difficulty of finding the bacillus in the discharges by 



