116 



Microscopic examination. — Lungs: Sections from the most con- 

 gested portions of the lower lobes show all the blood vessels, includ- 

 ing the interaveolar capillaries, to be engorged ad maximum. 

 Xumbers of air spaces are filled with a granular detritus including 

 desquamated cells, some white and a few red corpuscles. Mixed 

 with these elements are a moderate number of typical plague bacilli, 

 which in some of the alveoli are present to a considerable extent. 

 The majority of them are found in close proximity to the inner 

 lining of the alveolus and not free in the center of the air space. 

 Alveoli completely filled with innumerable plague bacilli are also 

 seen. In such masses of bacteria one occasionally encounters a 

 vessel broken into by these organisms ; this observation refers alike 

 to the capillaries, the veins, and the arteries. On the other hand, 

 a few interalveolar capillaries are found to be completely thrombosed 

 with densely packed plague bacilli. Alternating with alveoli, more 

 of less completely filled, are air spaces which are open and even 

 emphysematous, the interalveolar space having occasionally been 

 ruptured. Xo fibrin is found in any of the alveoli. Kidneys: 

 The most striking histologic change in the kidneys are metastatic 

 emboli in the glomerular capillaries, completely filling some of the 

 loops of the tufts. However, such emboli are foimd in a limited 

 number of glomeruli only; nor are any tufts seen where all the 

 capillaries are obliterated. The embolic closure is generally con- 

 fined to one lobe of a glomerulus. Sometimes the embolic bacterial 

 mass extends into the afferent or efferent vessel (it is impossible to 

 decide which of the two is affected). The neighborhood of such 

 thrombosed vessels shows small microscopic areas of blood extravasa- 

 tion, in which few bacilli are found. All the renal vessels are much 

 engorged, particularly the small vessels, and the interstitial tissue 

 is quite oedematous. Small microscopic areas of blood extravasa- 

 tion are encountered all over the sections. A few bacilli are often 

 seen in such areas as well as in the tubules, the lymph clefts, and 

 even occasionally in the small arteries and veins. The tubular 

 epithelium shows profound cloud swelling and fatty degeneration. 

 The interlobular capillaries of the liver exhibit the same metastatic 

 emboli, composed of dense masses of plague bacilli, such as have 

 been described above for the renal tissue. However, these bacterial 

 thrombi are not very numerous, and in general the liver capillaries 

 are free from bacteria. On the other hand, a small number of 

 bacilli were seen in one interlobular vein. The liver parenchyma 



