NOCARDIOSIS Q77 
through a colander. In the old nodules the center is caseous, soft 
and yellowish in color. The larger masses, composed of several of 
these smaller nodules, show on section yellowish areas varying from 
2 to 10 mm., separated by bands of fibrous connective tissue varying 
from .5 to 2 mm. in thickness. Radiating from these areas the inter- 
lobular tissue is very much thickened, the lung tissue being more or 
less collapsed. In a few of these nodules there are hemorrhages. 
“The lymphatic glands are very much pigmented and contain areas 
that are indurated and very firm to the touch. No calcification was 
found in any of the nodules or in the lymph glands.”’ 
\s Histological examination. A section of a small (young) nodule 
shows that it is composed of alveoli separated by a pronounced 
stroma of connective tissue. In most of the alveoli are desquamated 
and proliferated epithelial cells, which show parenchymatous degener- 
ation, some showing clear drops (mucus). In some alveoli are 
polynuclear leucocytes, mostly showing degeneration, and a few 
eosinophiles, some red corpuscles and fibrin. Some alveoli contain 
irregular felted masses of threads of bacteria. ‘These masses do not 
stain well. Individual threads may be seen projecting from the 
masses, but the main body is a tangle of filaments in which one can 
not follow individual threads for any distance. Between the alveoli 
the connective tissue is much increased, in places as wide bands, in 
others as narrower bands. The appearance under low magnification 
resembles that of an adenoma. The connective tissue is largely 
fibro-elastic. Many polynuclear leucocytes are found around the 
peripheral part of the nodule. The smaller bronchioles contain 
polynuclear leucocytes, masses of bacteria and desquamated epithelial 
cells. The bacterial masses in the young nodules are most abundant 
in the peripheral part of the nodules. 
“In larger (older) nodules and in scars the alveoli contain prolifer- 
ated and desquamated epithelial cells, some contain fibrin, red 
corpuscles, leucocytes and, in some are masses of bacterial filaments. 
The interlobular tissue is thickened and consists mostly of elastic 
tissue. The interalveolar tissue is widened, consisting of elastic 
tissue with some polynuclear leucocytes and fibrin.” 
Diagnosis. The diagnosis is made by finding the organism in the 
nodules or pneumonic areas. 
