TRYPANOSOMES, TRYPANOSOMIASIS, AND SLEEPING SICKNESS 41 
causes one not to rely on the presence of vacuoles. They often appear to be 
present in trypanosomes living under unfavourable conditions. In animals treated 
with arsenic, vacuolic forms can be seen. If non-vacuolated trypanosomes be injected 
into the peritoneal cavity of a guinea-pig and some of the fluid withdrawn after a few 
hours, many trypanosomes containing large vacuoles can often be seen. This is 
especially so with T. gambiense. The vacuoles seem more accentuated in stained 
films than in the fresh specimens. As Laveran points out this is especially observed in 
slides made from the cerebro-spinal fluid or from very serous blood. Films from 
such fluids take longer to dry even if the slide be warmed to blood temperature 
beforehand. 
If in a heavily-infected animal the parasites seen in its peripheral blood be 
compared with those met with in the organs, bone marrow, and large vessels, no 
differences can be made out. A series of animals were killed and the numbers of 
parasites present in the organ juices, heart, and large blood vessels compared with 
the peripheral parasites. In all cases the peripheral blood contained more, the 
average number of parasites in the different organs were the same. The various 
groups of glands did not contain more. On comparing the numbers found in the 
organs of animals which had died from the disease, at from one to twelve hours 
after death, the results have varied. If the blood be very serous more parasites will 
be found there than in the organ juices. Sometimes the bone marrow or one organ 
will contain more than the others. The brain and cord contain fewer than do the 
organs. 
Gland Puncture — Parasites in the Glands 
A study of the number ot the parasites in the glands as compared with those 
met with in the blood have not confirmed Greig and Gray's observations. From 
one native superficial glands were removed. Twice were glands taken at a period 
when the blood was negative to ordinary examination, and once when the blood 
contained a fair number of parasites. After excision the glands were immediately 
dried, the surface cauterized, and the gland juice withdrawn. When the blood was 
negative the glands did not show any parasites ; on the occasion when parasites were 
observable in the peripheral blood the gland juice contained a less number of 
trypanosomes. Gland juice was also removed by puncture with the same results. 
Similar findings are to be recorded with glands excised from or punctured in animals 
infected with the disease. Unfortunately, monkeys, rabbits, guinea-pigs, and rats do 
not usually have very enlarged glands, but in the other animals no better results can 
be shown. Gland puncture of two donkeys infected with T. gambiense and with very 
few parasites in their blood have not proved of use in the routine examination of the 
animals, though the glands were enlarged and easily palpable. Dutton and Todd 
have made use of gland puncture with very satisfactory results. 
F 
