ACUTE PHTHISIS. 



351 



from this central zone the alveoli are filled with catarrhal or 

 fibrinous exudations (Figs. 155 and 156). Near the centre 

 of the patch may be noted a bronchiole, its lumen filled with 

 desquamated epithelial cells and a granular debris. The walls 

 of the air- vesicles and bronchioles are infiltrated and somewhat 

 thickened. 



At a later stage these areas of consolidation reach the size 

 of a hazelnut or walnut, or they may involve an entire lobe or 

 even the whole lung. Although such a diffuse consolidation 



FIG. 155. 



A small soft gray tubercle from the lung in a case of acute tuberculosis. The whole 

 of the tubercle is shown in the drawing, and is largely constituted of intra- 

 alveolar products. X 100, reduced to (Green). 



may appear quite as uniform as that of lobar pneumonia, mi- 

 croscopically there is usually evidence of an original lobular 

 character of the inflammatory process. 



On section the surface of the affected areas, which have 

 become yellowish in color as the result of extensive caseation, 

 is generally smooth, though it may have a granular appear- 

 ance when the character of the inflammatory exudate is fibrin- 

 ous. The lungs may be fairly riddled with small, irregular 



