53 



Another bacterium present is a long, slender, well-stained bacillus. 

 The juice from the spleen contains a moderate number of plague 

 bacilli ; that from the liver and the kidneys a few only ; none at 

 all are found in the smear from the heart's blood. Cultures 

 inoculated from the inguinal glands and from the spleen developed 

 plague bacilli; a tube from the liver remained sterile. 



Microscopic examination. — The glands of the inguinal region 

 show a marked increase of connective tissue and thickening of the 

 walls of the vessels at the hilum. While some portions still 

 exhibit a fairly normal lymphoid tissue others are thoroughly 

 infiltrated with extravasated blood. The loose, areolar, pericapsular 

 connective tissue is infiltrated with mononuclear and polynuclear 

 inflammatory cells. Innumerable plague bacilli are difi:used 

 throughout the gland and penetrate into the periglandular con- 

 nective tissue. Here and there a moderate amount of fibrin is 

 seen, particularly around some small vessels, but hyaline thrombi 

 obliterating the vascular lumina are not visible. The capsule of 

 the spleen is not thickened, but the trabeculge are broad. The 

 Malpighian bodies are quite small, not sharply defined, and shade 

 off gradually into the surrounding tissue. The fibrillar connective 

 tissue of these follicles is increased. The pulp spaces are fairly 

 well recognizable and are densely filled with red blood corpuscles, 

 while a moderate number of polynuclears, some typical plasma cells, 

 and large mononuclear cells are also present. The last, which 

 appear to be proliferated endothelia of the pulp spaces, have a 

 large vesicular round or oval nucleus, not very rich in chromatin, 

 with generally one or more distinct nucleoli. A moderate number 

 of plague bacilli is found in the spleen sections. The kidneys 

 show both large and small vessels to be greatly engorged. There 

 is extensive cloudy swelling of the epithelium of the uriniferous 

 tubules, and a moderate amount of granular material is scattered 

 through the latter. The liver exhibits engorged capillaries and 

 a very moderate degree of fatty degeneration of parenchyma cells. 

 Very small interlobular inflammatory foci are seen in a few places. 

 The pulmonary tissue shows an enormous engorgement of the 

 blood vessels. • Most of the alveoli are open and empty, but a 

 moderate number contain red blood corpuscles, or more or less 

 granular material, in which are embedded leucocytes and shreds of 

 fibrin, the latter forming a network like that occurring in 

 fibrinous pneumonia. Plague bacilli are not found in such small 



