124 
Theileria parva 
TABLES I & II. 
Showing the percentage of infected red blood corpuscles and the percentage of such 
corpuscles which contained one, two, three and four or more parasites, commencing 
on the day when the parasites were first detected in the peripheral blood and ending 
on the day preceding that on which the cows died. These counts served for the con¬ 
struction of the accompanying charts. The percentage of infected corpuscles was 
usually determined by counting 250 consecutive corpuscles in the central portion of 
each blood film. The percentages of infected corpuscles containing different numbers 
of parasites are based upon the examination of 100 such corpuscles. The day on 
which the parasites appeared in the animal’s blood is reckoned from the day on which 
it was infested with pathogenic ticks (Rhipicephalus evertsi). 
Table I. (Cow I.) 
% r.b.c. 
infected 
% r.b.c. containing 
Day 
1 
2 
3 
4 or more parasites 
19 
5 
92 
8 
• 
. 
20 
10 
90-8 
7-6 
1-6 
• 
21 
16 
87-6 
11-2 
1-2 
• 
22 
25 
82-4 
14-4 
2-8 
•4 
23 
28 
82-4 
12-8 
3-6 
1-2 
24 
40 
80 
15-6 
4 
•4 
25 
56 
68-4 
22-4 
6-8 
2-4 
26 
51 
64-4 
26 
6 
3'6 
27 
52 
55-2 
32 
9-2 
3-6 
28 
62 
57-2 
30-4 
10 
2-4 
29 
62 
56 
27-2 
11 - 2 
5-6 
30 
60 
36 
37 
18-2 
8-8 
31 
75 
47-2 
32-4 
14-4 
•6 
32 
Cow died. 
Table II. 
(i Cow II.) 
21 
6 
92-8 
6 
•8 
•4 
22 
8 
88 
11-6 
. 
•4 
23 
13 
88-8 
10-8 
• 
•4 
24 
22 
80 
17-6 
2 
•4 
25 
26 
80-4 
16 
2-6 
1 
26 
32 
77-6 
19-6 
2-4 
•4 
27 
41 
80-4 
16-4 
3-2 
• 
28 
47 
67-6 
20-4 
9-2 
2-8 
29 
60 
68-5 
26 
5 
•5 
The distribution of the parasites in the blood from various organs. 
An examination of the blood corpuscles in smears made from various 
organs immediately alter death gave a remarkably uniform result with 
regard to the percentage of infected corpuscles and the relative numbers 
