286 
F. S. BILLINGS. 
animals suffering from perlsucht, and that perlsucht is not identical with 
tuberculosis. 
CATARRH OF THE LACTEAL DUCTS AND CHRONIC INTERSTITIAL MAS¬ 
TITIS.-FIVE CASES. 
The animals were of various ages between eight and ten years. 
From dissection one found nodules (perlknoten), from the size of a 
pea to that of a hazel-nut, upon the pleura and in the bronchial glands. 
There was a great quantity of a dense pus-like fluid discharged 
from the sinus lactiferi through the medium of the teat. From a micro¬ 
scopical investigation of this fluid, I found a considerable number of 
small cells containing a single large, or several small nuclei ; also, 
occasionally, epithelial cells from the alveoloe and excretory ducts hav¬ 
ing 2 to 3 nuclei. In some cases it discharged from the excretory ducts 
in a flocculent mass, in which I also detected round cells of the above 
described character. Here and there the excretory ducts are obstructed 
by a caseous mass, the greater part of which is composed of contracted 
granular cells, about the size of blood corpuscles, densely packed to¬ 
gether. Between these cells we also found round elements having a 
large nucleus and sharp contours. The mucosa of the sinus lactiferi 
and larger lacteal ducts are thickened. A superficial section is very 
compact, showing that the interstitial tissue is very much developed ; 
here and there we find cysts, varying in size from a pea to a man’s fist, 
which contains a caseous product. From this pulpy mass the micro¬ 
scope revealed small round cells with large single nuclei, and in the 
caseous mass shriveled pus-cells. In two cases only one gland was 
affected; in another both were affected in a manner described. 
Prof. Virchow recommended me to examine how far the catarrhal 
process extended, and whether the pus-cells originated from the 
catarrhal inflammation of mammary gland. 
In order to answer these questions, I investigated in these cases 
preparations which were prepared upon the method above described. 
I found in the interstitial tissue of the mammary gland connective tis¬ 
sue in a hyperplastic condition, and the connective tissue infiltrated 
with round granulation cells. The interlobular as well as the interal¬ 
veolar connective tissues had attained a threefold thickness. The 
excretory ducts were varicosely dilated, and their lumen obstructed with 
round elements from 0.003-0.006 m.m. in size containing a single large, 
or several small nuclei. It is only here and there that the membrana 
propria is in such a high degree of proliferation that it cannot be dis- 
