26 
Woolless sheep. This animal was killed as a test of the 
health of a flock. The only pathologic change which could 
be discovered in the entire body was an area of ten by eight 
by eight millimeters beneath the visceral pleura of the lateral 
surface of the right superior pulmonary lobe. This mass 
was yielding to palpation, smooth, apparently not infiltrating 
and was cut quite easily. Upon section, a cavity three by 
three by four millimeters was foimd, filled with a thick 
yellow cheesy material and surroimded by a fibrous capsule 
1 to 2.5 millimeters in thickness. Despite three unsuccess- 
ful attempts to demonstrate tubercle bacilli in this caseous 
matter, the writer made a diagnosis of encapsulated tuber- 
culosis, a diagnosis which he was obliged to retract when 
the microscope revealed the following growth. Under low 
magnification, there was a distended bronchus, surrounded 
by an irregular layer of tissue, on one side about three times 
as thick as upon the other. 
This wide band on one side is seen to contain epithelial 
nests and alveoli lined with epithelial cells, which are partially 
or wholly filled with epithelial cells. 
This is undoubtedly carcinomatous. The bronchus is 
distended and by following it proximally it is seen to possess 
cartilage plates and glands, which, with the lining of the 
bronchiole, are apparently normal throughout. Where the 
cartilage and glands were present together no carcinomatous 
change was found. This is the widest point of the cavity, 
and the carcinoma is distal to this section. . As one proceeds 
distally the bronchiectasis again narrows. Here is where 
the section of two millimeters is missing, and it may be that 
the exact origin of the neoplasm is in this narrow slice. Be- 
yond this, the lumen of the bronchus rapidly narrows to its 
normal proportions. The carcinomatous tissue appears be- 
fore the bronchiole returns to its normal calibre, and as the 
tumor is replete with connective tissue, it may have been 
and probably was the obstruction responsible for the bron- 
chiectasis. In the proximal portion of this bronchiectasis, 
where no tumor exists, the glands are normal in their ar- 
rangement, while in the lower section there are no cartilage 
plates, so that it is reasonable to suppose that no glands 
