658 



APPENDIX. 



Arrangement of the Capillaries of the air-cells of 

 the Human Lung. 



Morbid Lung. Diseased lung is examined in the manner de- 

 scribed above. Emphysema- 

 tous, tuberculous and pneu- 

 monic lungs present points of 

 the highest interest to the stu- 

 dent of pathological histology. 

 " A small fragment of tole- 

 rably firm miliary tubercle, 

 squeezed between glasses with 

 a drop of water, and examined 

 under a magnifying power of 

 250 diameters linear, presents 

 a number of irregular shaped 

 bodies, approaching a round, 

 oval, or triangular form, vary- 

 ing in their longest diame- 

 ters from the l-4000th to the 

 l-2000th of an inch. These are the so-called tubercle-corpuscles. 

 They are composed of a distinct wall, containing generally 

 three or more granules without any distinct nucleus, and are 

 mixed with numerous granules and molecules, varying in size 

 from a point scarcely measurable to the l-6000th of an inch in 

 diameter (Fig. 354, a). If we add to these bodies 

 a drop of weak acetic acid, all the corpuscles 

 become more transparent, but are otherwise 

 unchanged, and many of the granules disap- 

 pear, as in Fig. 354. 6." 



^ Yellow tubercle treated in the same manner 



?<&'{$ ^ % P.Q presents similar corpuscles imbedded in a mole- 

 ^JS't' ^P-^' cular and granular mass (Fig. 355). Sometimes 

 ^ these corpuscles are observed to be larger and 

 rounder, resembling in this respect those of 

 scrofulous pus (Figs. 356, 357). Occasionally tuberculous matter 

 will be seen to consist almost entirely of granules, and at other 

 times of very minute molecules. 



FIG. 354. 





FIG. 3f>5. 



FIG. 356. 



FIG. 357. 





A thin section of the gray, semi-transparent granulation is 

 very different in appearance from ordinary tubercle. The con- 

 stituent elements, though more transparent, are less distinct 

 (Fig. 358). In the cretaceous and calcareous forms of tubercle 



