CELLULAR CONTENT 
45 
in the follicles, save when these contained blood. Large mono-nuclear 
leucocytes were found frequently in the lymphatic tissue, and in greater 
numbers in cover-slip preparations taken from the vein draining a node. 
In the arteries, on the other hand, and in the blood islands, they were 
found in smaller numbers only. 
Although individual phagocytes could usually be found, marked 
phagocytosis was not a constant phenomenon. In some cases, however, 
the whole section was dotted with scattered polymorphonuclear leuco- 
cytes, which were filled with fragments of erythrocytes and fairly 
well preserved cells. These phagocytic leucocytes were not much en- 
larged, as a rule, and were always well preserved. In some cases, how- 
ever, so many and such extremely large phagocytes were present that the 
whole section of a node was seen to be studded with them on lower power 
(x 42) magnification. Since these large cells were filled so completely 
with erythrocytes and fragments of such, they gave the section the ap- 
pearance of containing numerous small blood islands or areas. The nu- 
clei of these large endotheloid cells, a group of which was sometimes 
contained in a follicle, were large, oval and vesicular. Occasionally simi- 
lar isolated cells were found in small numbers, in the hemal areas of nodes 
in which phagocytosis by polymorphonuclear leucocytes was very active; 
but this association was not at all constant. 
Besides typical eosinophiles, which were sometimes exceedingly nu- 
merous and rarely arranged around an artery (see fig. 26), others with 
less evident granules were not uncommonly present. These were usually 
most evident in sections of nodes fixed in acetic bichloride and stained in 
haemotoxylin followed by rubin S. Besides these atypical eosinophiles, 
other generally much larger acidophile cells with vesicular and occasion- 
ally pyknotic nuclei, were also found in developing and mature nodes. 
They varied considerably in size, and were undoubtedly phagocytic in 
some cases. 
The most uncommon cells found in the course of this investigation 
were of course the poly- and megakaryocytes, of varying sizes and 
shapes. Some of these multi-nucleated ( ?) cells were extremely 
large, and had a very irregular outline. In fact they were rarely so irreg- 
ular that the outlying portions suggested the occurrence of pseudopods 
and amoeboid motion. These cells, which were usually found in the 
lymphatic tissue, were sometimes surrounded more or less completely by 
an empty space of varying width, which was, however, seldom so large 
as to accommodate additional cells. Although more numerous in devel- 
oping nodes, there was nothing which indicated that they are character- 
