94 Equine Piroplasniosis 
Changes in the blood. 
Differential count of leucocytes 
Day 
R.b.c. 
per c.mm. 
Haemoglobin 
Leucocytes 
per c.mm. 
Eosin’s 
Mono’s and 
Neutroph’s lympho’s 
1 
— 
— 
— 
30 
53 17 
2 
— 
8,800 
3 
6,400,000 
— 
4 
— 
0-207 
. — 
5 
6,570,000 
— 
6,850 
8 
6,700,000 
— 
6,600 
10 
— 
0-189 
— 
11 
6,685,000 
— 
— 
12 
— 
0-192 
— 
17 
5,872,000 
0-155 
5,300 
0 
83 17 
18 
4,140,000 
0-178 
— 
19 
4,960,000 
0-185 
Mean of two read¬ 
ings in each case, 
being 0 capacity 
of 1 c.c. of blood 
in c.c. 
Mean of ca., ten 
readings in each 
case. 
From the foregoing record we see that the body temperature rose on the 9th day, and 
that the parasites appeared on the 10th day after inoculation. Following upon the initial 
rise of temperature there was a fall and then a rise, the temperature attaining 10'5'6°F. on 
the 16th day. The red blood corpuscles were not materially decreased in numbers except 
toward the end, and the haemoglobin content was not appreciably altered. There was a 
fall in the number of leucocytes. The parasites multiplied rapidly only during the last 
36 hours, but they never infected more than 0-5 ®/q of the corpuscles. 
Note upon the chemical method of haemoglobin determination used 
in this investigation. 
The oxygen capacity of the blood was investigated by direct measurement of the 
oxygen which it contained when shaken with air. The method employed was that form 
of the differential method described by Barcroft and Koberts (Journ. of Physiology, xxxix. 
p. 435, 1910) and based upon the observation of Haldane, that ferricyanide of potassium 
liberated, from an alkaline solution of haemoglobin, an amount of oxygen equal to the 
respiratory oxygen contained combined with the pigment. 
The method is briefly as follows : 
Into each of the bottles is placed 0-2 c.c. of dilute ammonia solution (made by adding 
1 c.c. of NHg, SG -880 to 250 c.c. of water) and about OT c.c. of blood, accurately 
measured from a pipette. The present experiments were performed with 0-082 c.c. The 
fluids are gently shaken so that the blood becomes laked and thoroughly oxidised. The 
bottles may then be placed on the apparatus, but before this is done a drop of potassium 
ferricyanide is placed in the pouch projecting from the side of one of the bottles. The 
