Hepatization. — Infarction. 49 



particular air tubes and blood yessels, as will be explained 

 further on. The fact, however, is noteworthy as charac- 

 teristic of this disease, that it attacks entire lobules, and 

 the limits of the diseased lung tissue are usually sharply 

 marked by the line of connective tissue between two lob- 

 ules, so that one lobule will be found consolidated 

 throughout, and the next in a perfectly natural condi- 

 tion. 



The two forms just described differ also in cohesion 

 and power of resistance. The lung saturated with the 

 liquid exudation has its intimate elements torn apart and 

 is more friable, giving way readily under pressure, 

 while that in which there is red congestion but no ex- 

 tensive exudation, retains its natural elasticity, tough- 

 ness and power of resistance. 



Hepatimtion. — Another condition of the diseased lung 

 tissue, more advanced than either of those just described, 

 is the granular consolidation or hepatization. In this con- 

 dition the affected regions of lung are as much enlarged as 

 in the dropsical condition, but they are firmer and more 

 friable, and on their cut surface present the appearance 

 of little round granules. These granules are not pecul- 

 iar to the lung tissue proper, though most marked on 

 this; they characterize the interlobular connective tissue 

 as well. They consist mainly of lymphoid cell growths, 

 filling up the air cells, the smaller air tubes, the lymph 

 spaces and the meshes of the connective tissue. The 

 color of these portions varies from a bright reddish-brown 

 to a deep red, according to the compression to which the 

 lung tissue has been subjected by the exudation in the 

 early stages. (See Heliotype.) 



Infarction. — Another form of lung consolidation is of 

 a very dark red or black and always implies the death of the 

 portion affected. The dark aspect of the diseased lobules 

 forms a strong contrast with the yellowish-white interlob- 

 ular tissue, excepting in cases where that also becomes 

 5 



