TRYPANOSOMES, TRYPANOSOMIASIS, AND SLEEPING SICKNESS 83 
formation were found in all the groups. Very often the lymphoid tissue was not 
confined by the capsule, but was also found external to it, and lymphocytes were also 
interspersed in the adipose tissue. The germ centres in some of the glands were 
normal, but in others they were broadened out with numerous gaps in their continuity, 
whilst in others still they were not recognizable at all. The lymphoid tissue was verv 
often interspersed with a large number of red cells, so that in the specimen stained 
with methylene blue lighter areas of unstained red cells and darker ones of lymphoid 
tissue were met with. The vessels often had accumulations of red cells around them, 
and in their lumen many white corpuscles. 
Among the various cells found inside the sinus and outside it were very numerous 
phagocytic cells with red blood corpuscles, which in the specimen stained with modified 
Laveran's method, were deeply stained orange ; other cells were mono- and polv- 
nuclear leucocytes with eosinophile granules ; cells of the size of large mononuclear 
leucocytes having small nuclei and basophile granules ; giant cells in limited numbers ; 
occasional cells such as are found in bone marrow, of an irregular oblong shape, 
staining a peculiar dark blue colour with haemotoxylin and containing one or more 
vacuoles, the protoplasm presenting a meshwork with one or two darker-stained spots 
in it ; and a few plasma cells. Blood pigment, which gives the Prussian blue reaction, 
was present in nearly all the glands. 
The sections of the bone marrow of the femur showed the ordinary constituents 
of marrow ; nucleaed red cells were present in small number. The vessels were con- 
gested, and around them were very often accumulations of red blood corpuscles. 
Some parts presented typical gelatinous degeneration. In one place in the medullary 
substance of the left suprarenal was an infiltration of lymphocytes. The testes and 
epididymis were normal. 
Brain and spinal cord showed the same changes as in the previous case, but to a 
far less extent. The pia and arachnoid over the cerebellum and over the convexity, 
more especially, of the cerebrum, presented a small-celled infiltration. The vessels 
were highly congested. The small-celled infiltration accompanied the vessels into 
the cerebral cortex. Many of the vessels of the cortex, however, were free from this 
perivascular infiltration, and only showed enlargement of the perivascular lymph spaces. 
The vessels of the grey basal ganglia were the most affected. The perivascular 
lymph spaces were occupied by a cellular accumulation consisting of lymphocytes, 
red blood cells, and a few plasma cells. The same changes were, observed around 
the vessels of pons and medulla, while in the cord they were very little marked ; here 
the vessels have often a much-enlarged perivascular lymph space with a few 
lymphocytes in it. The cord showed a gliosis of its central canal. The nerve fibres 
presented very little degeneration, while the nerve cells, however, showed different 
stages of chromatolysis and pyknosis, more pronounced in the brain, however, than 
in the cord. The bacteriological staining methods revealed a varying number of large 
