PATHOLOGY. 211 



visible. In the stage of inflammatory engorgement, the plague- 

 infected lung was voluminous, firmer, and less crepitant than the 

 normal lung, and either dark red or reddish blue in color. Upon 

 section, the tissues were found to be very cedematous, and a thin, 

 reddish serum escaped in great abundance. 



The pneumonic areas, when present, were either lobular or 

 lobar in type. (See Plates VIII, IX, and X.) 



In the lobular type, one or several nodules varying from about 

 three to five centimeters in diameter might be found in the lobe. 

 They were rather sharply circumscribed from the surrounding 

 lung tissue by a more or less marked ring of engorged pulmonary 

 tissue and were either circular in outline or wedge-shaped. In 

 one instance, on section of the lung, six areas in the stage of 

 early gray hepatization were observed in one lobe situated near 

 the base. Three of these measured 2, 1.5, and 1 centimeters in 

 diameter and were all arranged along the same bronchus. About 

 one-half centimeter from the tip of the base of the lobe on the 

 same bronchus were three more hepatized patches measuring 

 5 or 6 millimeters in diameter. The mucous membrane of the 

 bronchi was dark red in color. The other lobe and the right 

 lung in this case showed only congestion and oedema. Some- 

 times these pneumonic areas are situated on the surface of the 

 lung, when they project distinctly from the surrounding lung 

 tissue, and the pleura over them is roughened and shows other 

 signs of early inflammation. Such areas of broncho-pneumonia 

 as just described no longer contained air. On cut section the 

 surface was rather dry, grayish red in color, and finely granular 

 in appearance. No muco-purulent secretion was visible in the 

 smaller bronchi, and, on pressure, mucus plugs were not ex- 

 pressed from the bronchi as is frequently the case in bronchial 

 pneumonia due to infection with other microorganisms. The 

 granular appearance of these areas is not identical with that 

 observed in croupous pneumonia. The gi^anules are irregular 

 and coarser, and, on scraping the surface of these areas with 

 the knife, no fibrin plugs are observed to escape from the air 

 cells, but the juice so expressed is grayish white, slightly sticky, 

 and evidently highly albuminous. The alveolar septa some- 

 times appear broader than normal. The mucous membrane of 

 the bronchi leading to such areas was bright red in color. Occa- 

 sionally several pneumonic areas might be arranged along one 

 bronchus somewhat as the flowers of the hydrangea are placed 

 on the stalk of the plant. 



While a careful study of the human lungs, as well as of those 



