660 APPENDIX. 



tinge. As the tubercle becomes older, the pigmentary matter 

 generally increases in quantity. It also varies in chemical com- 

 position according to its situation. That obtained from the 

 lungs and bronchial glands is pure charcoal and chemically 

 indestructible ; that found in the peritoneum is destroyed by the 

 action of alcohol and the mineral acids. 



Gulliver, Vogel, and Schroeder Van der Kolk affirm, that 

 nucleated cells may be observed in miliary tubercle ; but both 

 Lebert and Bennett deny it. (Figs. 361, 362.) 



It is oftentimes very difficult to distinguish tubercle from 

 fibrinous exudations and from cancerous growth. " If we are 

 asked," writes Prof. Bennett, "to determine what is positively 

 tubercle, as distinguished from all other morbid products, we 

 must answer, that deposition which is composed of the peculiar 

 corpuscles and granules described and figured in the preceding 

 pages. From pus-corpuscles they are readily distinguished by 

 the action of acetic acid, which in them causes no granular 

 nucleus to appear. From plastic corpuscles they may be sepa- 

 rated by their irregular form, smaller size, and the absence of 

 primitive filaments. With the granular corpuscle they can 

 scarcely ever be confounded, on account of its large size, brown- 

 ish or Ijlackish color, and nucleated or granular structure. The 

 cells of cancer are large, transparent, and distinctly nucleated, 

 and, consequently, easily distinguished from the small, non- 

 nucleated corpuscles of tubercle." "The only other structure 

 likely to be confounded with tubercle is the reticulum of cancer, 

 which not only presents a yellowish appearance closely resem- 

 bling it, but is composed of nuclei and molecular matter result- 

 ing from the disintegration of cancer-cells. But, as this reticu- 

 lum is always associated with cancerous formation, it may at 

 once be distinguished by the cell-elements which accompany it. 

 It should further be noticed that every form of exudation, at a 

 certain period, presents a molecular and granular structure 

 throughout, and that then it becomes impossible to determine 

 its nature, unless it be associated with the more characteristic 



Fio. 364. Fia. 365. Fig. 366. 



Fig. 363, A, Tubercle corpuscle from lung; b, Pus corpuscles. Fig. 364. PlRslic, or pyoid cor- 

 puscles. Fig. 366. Granular corpuscles from cerebral soflening. Fig 366. Corpuscles in reticulum 



of cancer. 



elements distinctive of the simple, tubercular, or cancerous 

 exudations." The accompanying figures will illustrate these 

 distinctions. (Figs. 363, 364, 365, 366.) 



