134 OEIENTAL PLAGUE chap. 



of B. pestis \ some capillaries and small veins appear almost injected, 

 i.e. completely filled, with these bacilli. 



4. The like is the case with the liver, where the capillaries between 

 the columns of liver cells are in many parts continuous masses of 

 plague bacilli, the liver cells at the same time showing granular 

 degeneration. 



5. In the kidney all parts are uniformly congested, with many 

 capillary haemorrhages ; many vessels of the cortex as also of the 

 medulla are injected with plague bacilli. This is very strikingly 

 shown in some of the Malpighian tufts and in their afferent and 

 efferent vessels. The masses of bacilli being stained blue — methylene- 

 blue — the specimen now looks, under moderate magnification, as if 

 some of these vessels had been actually injected with blue colouring 

 matter. Granular degeneration and breaking down of the epithelium 

 is seen almost everywhere in the convoluted tubes. Plague bacilli 

 are seen in the uriniferous tubules both of the cortex and the 

 medulla. 



In respect of the rapid absorption and multiplication of plague 

 bacilli in the inguinal glands after cutaneous inoculation, their rapid 

 distribution all through the viscera and their enormous multiplication 

 therein, the mouse is undoubtedly the animal offering the best nidus 

 for the growth and multiplication of B. pestis. The above description 

 applies equally to mice dead within forty hours and to those dead 

 within sixty or sixty-six hours. 



III. — Rats inoculated cutaneously with Attenuated Plague Type No. 2 



As was mentioned in the experiments already described, death 

 of such animals was delayed, and, except as regards the inguinal 

 bubo and spleen, they showed comparatively few changes in their 

 viscera. The changes consisted of a more or less general con- 

 gestion, less in intensity than in the animals dead of the virulent 

 type. The inguinal glands presented very much the same character 

 as after cutaneous inoculation with plague of the virulent type, and 

 also the spleen was in some instances found enlarged, dark, and 

 firm, in others only slightly or not appreciably so. 



Examination of sections through the hardened organs of rats 

 dead after cutaneous inoculation with plague of type No. 2 was 

 undertaken in a number of instances. The rats thus minutely 

 examined were : — 



