37 2 
In contrast to what is seen in blood films made 
by spleen or liver puncture where most of the parasites 
are either free or contained in a matrix, in sections no 
such relation exists ; the parasites lie in cells. These 
cells are of various types. 
(a) But slightly modified endothelial cells. These have an 
oval nucleus and extensive protoplasm showing vacuolization (Fig. 20). 
The protoplasm may show buds or protrusions. These cells contain 
six to twelve parasites. Identical cells are seen in the capillaries of 
the testis and of granulation tissue. 
(b) Large round cells with a large nucleus. The protoplasm has 
a ground glass appearance and is vacuolated. In the testis and in 
granulation tissue these cells are attached at one point to the capillary 
wall, the rest of the cell projecting freely. They also occur in the 
blood taken post-mortem from the large veins. They contain twenty 
or more parasites (Fig. 21). 
(c) Very large cells with one or two vesicular nuclei. They occur 
in the liver and spleen in immense numbers. They occur either 
extended along the capillary wall or in a retracted form. In the 
spleen their processes extend among the smaller cells of the pulp. 
They contain numerous parasites. 
( d) Large cells staining more intensely than the last and some¬ 
times showing signs of necrosis. The nucleus is pushed to the side. 
The centre of the cell is occupied by a large vacuolated space, around 
which are arranged numerous parasites. The cells, in fact, contain 
so many parasites that they appear to be on the point of rupture, 
and such cells are rarely seen whole in films unless fixed extremely 
carefully with osmic acid vapour. They contain as many as two 
hundred and fifty bodies (Figs. 22, 23). 
Bone marrow .—In films the parasites occur in macrophages in 
immense quantity. To some extent also in large mononuclear cells, 
and a few in polynuclear cells, and in myelocytes. 
Large intestine .—Parasites occur in large numbers in the granu¬ 
lations, and in the mucous membrane in the early stages of infiltration. 
They occur in similar cells to those found in other situations. 
Granulation tissue .—Sections of papules or ulcers of the skin 
show a few parasites in what are apparently endothelial cells of the 
fine capillaries. In larger capillaries cells may contain three or four 
parasites, while in small vessels large cells similar to those in the liver 
and spleen are found crowded with parasites. These cells are attached 
at one point to the capillary wall. 
