54 
HEMOLYMPH NODES OF THE SHEEP 
ably thicker than usual, and a very coarse and imperfect reticulum was 
noticeable by means of the ordinary stains. It is, however, the above 
referred to acidophile phagocytic cells with a hyaline like protoplasm 
and the presence of pigment, which gave sections of some of these nodes 
the prominent distinguishing microscopical characteristics. These acido- 
phile cells are occasionally so numerous and so large that they are plainly 
evident under low-power magnification. In contrast to the lymphocytes 
and erythrocytes, they are most abundant in the depleted portions, and 
gradually decrease in number as the more typical portions of the node are 
approached. In the depth of the latter they are practically absent. 
Though most of them are fairly circular in outline, some are quite irregu- 
lar in form. In some cases this irregularity of form seemed to be due 
to degenerative changes, or slight lobulation; but many of them had dis- 
tinct processes, and looked exactly like branched connective tissue cells, 
and must, I believe, be regarded as having at least partly such and a retic- 
ular origin. On some of these cells which lay isolated, processes could 
be seen which were in continuity with the coarser reticulum or with the 
cells at the border of the trabeculae. In addition to those shaped like 
ordinary branched connective tissue cells, others with a greatly elongated 
cell body with a process at each end were also found. Although but a 
single terminal process or a bifurcated one was seen, as a rule, other pro- 
cesses may, of course, have extended in other planes and directions. The 
nuclei of these cells are vesicular, irregularly oval in outline, fairly cen- 
tral in position, seldom larger than twice the size of the erythrocytes, and 
contain but few chromatin granules. Usually only one nucleus is present, 
but it is not uncommon to find polynuclear cells. The cytoplasm, which 
is abundant and takes an acidophile stain, is non-granular or nearly so in 
non-pigmented cells ; but cell inclusions are very common. The latter 
usually have the form and appearance of laked erythrocytes, and, if exter- 
nal appearances are a sufficient guide, may be designated positively as 
such. One or two such cellular inclusions are very common, and speci- 
mens with four or more occasionally occur. While most of the cells con- 
taining erythrocytes are non-pigmented, many of those without inclu- 
sions have a protoplasm which is very densely filled with golden or brassy 
pigment granules. This intra-cellular pigment is not confined to the cell 
body, however, but is also found in some of the processes. Although the 
proportion of the intra- and extra-cellular pigment varies considerably in 
different nodes, the size of the granules is quite uniform. Special tests 
for iron were used repeatedly on sections from these pigmented specimens, 
but no positive results were obtained. It is of particular interest in this 
connection that similar pigment and acidophile cells undoubtedly phago- 
