THE MICROSCOPE. 203 
by Roth. I had the opportunity, under guidance of Prof. Dr. von 
Recklinghausen, of examining carefully twenty-five cases of this 
kind. These researches were especially directed to the answering 
of two questions: (1) Whether the pigment deposited in the 
abdominal organs corresponded microscopically and chemically with 
that of the enlarged, and for the most part slaty indurated 
bronchial and tracheal lymphatic glands; and (2) whether the 
pigment was always present in the abdominal organs, when such a 
gland had perforated the walls of a vessel or bronchus. 
If the organs contain anthracotic pigment it is by no means 
necessary that they should be changed; they may be normal in size, or 
they may become enlarged or atrophied, although the two latter 
changes are not the result of the deposit of pigment, since the pig- 
ment produces no irritation whatever in the structure of these 
organs. The pigment is for the most part taken up by the cells and 
especially by the leucocytes. Within these organs only it occasion- 
ally leaves the cells and settles in them. 
THE SPLEEN. 
In the spleen it lies principally along the smaller arteries 
(perivasculz) and in the marginal zone of the malpighian-bodies 
(corpuscles), and is also found in the perivascular lymphatic 
canaliculi, and in the lymphatic vessels of the capsule; it is for the 
most part confined to cells, especially leucocytes (round cells), and 
even to the spindle-shaped and star-shaped cells. It presents a 
fine-grained black pigment which is not affected by caustic soda or 
potash, caustic ammonia, muriatic, nitro-muriatic, sulphuric acid and 
ferrocyanide of potash. It is not affected by the various coloring 
materials which are used in staining the tissues. The coloring 
fluids which I have used especially are: Carmine, Ranvier’s 
picro-carmine, alum-carmine, Orth’s lithion-carmine, borax-carmine, 
hematoxylin, and various anilin colors, such as gentian-violet, 
methylene-violet, methylene-blue, fuchsin and several others. The 
black liver- and spleen-pigment correspond exactly, as well micro- 
scopically as chemically, with the coal dust of the lungs and of the 
bronchial and tracheal-lymphatic glands. 
IN THE LIVER 
It is very rarely visible macroscopically. If it is present it assumes, 
as is well known, and as Weigert points out, a light-gray color. 
Microscopically it is seen deposited especially in the periportal 
interacinous tissue along the small arteries, at times also within the 
cells of the tissue along the vena centralis, also in the lymphatic 
vessels of the capsule and in the periportal (interlobular) lymphatic 
