HISTOLOGY OF THE MAMMARY GLAND. 
279 
large, and they assume a cubical form as they enter the alveole, being 
0.012 m.m. in size. In the smallest excretory ducts, I find the mem- 
brana propria possesses all the above mentioned characters. Their 
striae runs parallel to the length of the excretory duct, the distance 
between each being from 0.009-0.015 m.m. The membrana propria 
could not be recognized in the excretory ducts; in its place I saw inter¬ 
weaving connective tissue fibers lying parallel to the length of the 
excretory ducts, as Henle has described in the mamma of the calf. 
In the interlobular connective tissue, I found oval, stellate and 
spindle-shaped connective tissue cells, and elastic fibers as well as non- 
striated bundles, from 0.015-0.045 m.m. in thickness, surrounding the 
lobule. In these muscular bundles, particularly after staining the pre¬ 
parations with hematoxylin, I could distinctly recognize the non-striated 
muscular cells (myoblasts) having the following dimensions 0.030 m.m. 
long and 0.003-0.006 m.m. in diameter. The width of the interlobular 
connective tissue is from 0.180-0.510 m.m. The arteries and veins fol¬ 
low the same course as the excretory ducts. The capillaries wind 
spirally round the alveoloe, or form a network upon the external surface 
of the membrana propria.* 
After these histological discussions, I will describe the anatomical 
changes upon the mammary gland of the cow from perlsucht. 
Perlsucht, as is known, is peculiar to cattle, and develops itself 
upon the pleura and peiitoneum in dense nodule the size of peas or 
hazel-nuts, appearing either as large, single papilliform tumor, or as 
small clusters united to each other and to the surface of the serosa by 
fibers of connective tissue. These are known in pathology under the 
name of nodule (perlknoten). The sectional surface of these neoplasms 
presents a dense and coarsely fibered appearance in the peripheries, and 
are soft and fine fibered in the center. In the latter case the center is 
caseous or calcareous. The lymphatic glands most frequently suffer 
from metastasis of the neoplasms, but sometimes the lungs and other 
organs are often complicated. As early as 1817 Dupuy described perl¬ 
sucht as a specific disease, identical with tuberculosis of the human sub¬ 
ject. In the year 1831 Gurlt (Lehr buch der pathologischen Anatomie der 
Havasangethiere), was opposed to Dupuy’s opinion, and considered the 
nodule as sarcoma. 
Virchowf was the first to thoroughly examine these neoplasms and 
* The blood vessels were injected with the following: Berlin blue, 5 gr. ; oxalic acid, 5 gr. 
gelatine, 50 grs.; aqua, 50 grs. 
t Virchow. Wurzburger Verhandl., 1857, vol. 8, p. 143. Geschwulste, vol. 2, p. 739. 
