68 THOMPSON YATES AND JOHNSTON LABORATORIES REPORT 
or white cells, or both, 1 have here described it as clear, slightly cloudy, or cloudy. If 
with blood only the cloudiness has a pink tinge, but if with white cells only it has no 
pink tinge. It is invariably clouded almost immediately after death by excess of 
white cells. The colour and extent of the cloudiness is best gauged by looking 
down and not through the centrifuge tube. 
The fluid, as soon as drawn, should be centrifugalized gently for fully five 
minutes. It can then be poured off to the last drop into another tube, leaving only 
the resulting small deposit, which can then be picked up with a fine pipette, placed 
on a slide and systematically examined under a coverglass well ringed with vaseline, 
with a one-eighth or one-sixth objective, and a No. 4 eyepiece. If centrifugalized 
violently for a length of time the activity of the trypanosomes may be much decreased, 
and, consequently, the labour of searching for them more difficult, and if there is 
much deposit they may even be mutilated by the pressure of the cells. I have found 
it far better to centrifugalize the fluid a second time after the deposit from the first 
centrifugalization has been examined, for, owing to degeneration changes, which com- 
mence in the cells almost as soon as the fluid is drawn, it is best to examine it and 
fix some films without delay. It is imperative that the fluid should be centrifugalized 
a second or even a third time if possible, for, on two occasions at least, I have found 
trypanosomes in the second deposit and not in the first. If there is no deposit in the 
tube the lowest fluid should be pipetted without pouring off, for the parasites are 
easily poured away with the fluid. 
With regard to the white cell elements, I have described them as very scanty, 
scanty, increased, and much increased, and I have assumed that very scanty is the 
normal condition. The difference between these various degrees is difficult to make 
out, and is apt to depend upon the amount of fluid allowed to remain with the 
deposit. 
Table V 
L.P. 
Very Scanty 
Scanty 
Increased 
Much Increased 
Totals 
Tryps. present 
3 
1 1 
31 
Tryps. absent 
7 
I 0 
I 
43 
Total ... 
1 0 
35 
2 I 
8 
74 
The majority of the punctures come under the headings of scanty or increased, 
viz., forty-six per cent, under the former, and twenty-six per cent, under the latter, 
leaving about thirteen per cent, for both very scanty and much increased. 
