462 TUBERCULOSIS. 



due to the lack of blood-vessels, therefore to an insufficient sup- 

 ply of nourishing material. In this condition the infiltration 

 may persist as a tissue for quite a time. It is only after the 

 shriveled, and in part fatty, elements are disconnected from the 

 mother-tissue, and from each other, that the crumbly and friable 

 mass becomes a foreign body, like pus. It then is subject either 

 to being encysted or to softening, to liquefaction from without, 

 and to necrosis. The first process is the result of an inflamma- 

 tion of the surrounding vascularized tissue, leading principally 

 to a new formation of callosities ; the second process is due to an 

 inflammation of the surrounding tissue, leading mainly to an 

 exudation and suppuration. In consequence of the suppuration 

 at the inner surface of the inflamed capsule serous pus arises, 

 mingled with crumbs, and a cavity filled with pus an abscess 

 is formed. The softened mass may become innocuous by a 

 process of fatty and calcareous metamorphosis, and, as such, will 

 not excite a new inflammation. 



The " caseous metamorphosis " of Virchow, therefore, is due to 

 a shrinkage, a desiccation of the new formation, which is inflam- 

 matory in the tubercle, in consequence of the absence of nourishing 

 Hood-vessels. The softening of the " cheese," on the contrary, as 

 has been already maintained by Lombard and Andral, is invari- 

 ably due to a hyperaemia or inflammation of the vascularized 

 neighboring tissue, and to a stagnation in its blood-vessels, which 

 is frequently accompanied by haemorrhages and followed by the 

 formation of pigment. In this manner, the tubercle is removed 

 from the group of the lymphomatous new formations and the tuber- 

 cular product deprived of all specificity. 



Comparison with Suppuration. It only remains to draw the 

 parallels between tuberculization and suppuration, as these proc- 

 esses are evidently kindred to each other. Reinhardt, who con- 

 sidered the tubercle as an inflammatory product, arising from an 

 exudate (1847), declared the yellow tuberculous matter to be meta- 

 morphosed pus. This conception has nothing in common with 

 our ideas. That pus may become " cheesy," in consequence 

 of an absorption of its liquid portions, and that pus-corpuscles 

 under these circumstances may be 'transformed into tubercle 

 corpuscles, a process which Andral has termed tuberculization of 

 pus, is unreservedly admitted. But this does not by any means 

 prove that suppuration and tuberculization are identical processes. 

 In suppuration there is also a stage in which the diseased tissue, 



