W. L. Yakimoff and others 
55 
On the 17th day — 1 : 398 
5 J 
30th 
„ = 1 : 268 
35th 
„ = 1 : 220 
43rd 
„ = 1 : 179 
5? 
57th 
„ = 1 : 286 
5 5 
65th 
„ = 1 : 244 
5 ? 
72nd 
„ = 1 : 237 
79th 
„ = 1:112 
This shortage is due to simultaneous oligocythaemia and leucocytosis. 
(4) The leucocytic formula. Previously to infection the forms of leucocytes 
in this foal were distributed as follows: 
lymphocytes 
37-3 
mononuclears 
1-0 
transitionals 
4-2 
polynuclears 
45-7 
eosinophils ... 
6-5 
mast cells ... 
0-3 
myelocytes ... 
0-8 
Tiirck’s Keizungsformen ... 
3-7 
During trypanosomic infection the most conspicuous role belongs to the 
lymphocytes and neutrophil polynuclears. 
Lymphocytes. On the day of infection, several hours after the inoculation 
of blood containing trypanosomes, the percentage of lymphocytes began to 
increase and from this day the curve began to rise with some fluctuations, 
reaching 70-3 % on the 19th day (the day of appearance of trypanosomes in 
the blood). Having fallen in the next 3 days to 43-3 %, 50*6 % and 36 %, on 
the 26th day the curve again rose to 62 %, and later, during the whole time 
up to the death of the animal, it stood high (to 74-6 % on the 36th day), only 
descending twice to 31 % and 21 %, respectively. 
The curve of the neutrophil polynuclears presents the reverse of the curve 
of the lymphocytes: whilst the latter rises, the curve of the neutrophils 
falls, and vice versa. On the day of the highest lymphocytosis (74-6 %) there 
were only 7 % of polynuclears (on one occasion—on the 23rd day—the 
percentage was even lower—4 %). 
During the whole period of the disease the percentage of the polynuclears 
was above the average; previously to infection only three times (on the 7th 
and 8th days—52-3 % and 47*3 %, on the 13th—52*6 %, and on the 73-75th 
—52 %-62 %), and on the two last days preceding death (46 % and 45*3 %). 
The first rise (7th and 8th days) indubitably occurred on the day of 
penetiation of the trypanosomes into the blood (mouse No. 21 inoculated 
with the blood of the foal on the 9th day became infected). This increase of 
the polynuclears may be termed the period of primary polynucleosis. 
