433 
From these tables it will be seen that young and light rats, such 
as Numbers 18 and 33, are less resistant than older and heavier 
rats, e.g., Numbers 1 and 23. 
It will also be seen that when the initial rise is rapid and high 
the rat soon dies, and does not show periodic variation. 
COMPARISON OF THE TWO STRAINS IN RATS 
We now append a table, for purposes of easy comparison, 
of various points regarding the two strains in rats. The figures 
are compiled from the foregoing data, and relate to enumerations in 
seventeen rats exhibiting periodic variation, and of five rats 
exhibiting continuous rise in the case of T. rhodesiense ; also of seven 
rats exhibiting periodic variation and of four rats showing 
continuous rise in the case of T. gambiense. 
(a) 7 '. rhodesiense 
No. 
Colour 
Weight in 
grams 
Incubation 
period in 
days 
Duration 
of life in 
days 
No. of 
Trypanosomes 
inoculated 
Approximate 
No. of Divisions 
in first 24 hours 
I 
Piebald 
187 
2 
'4 
1 million 
3 
2 
White 
108 
2 
10 
350,000 
7 
3 
White 
225 
1 
9 
2 million 
8 
4 
Piebald 
220 
3 
'3 
500,000 
8 
5 
White 
120 
3 
11 
750,000 
2 
6 
Piebald 
100 
3 
9 
1 million 
8 
7 
Piebald 
i8q 
2 
9 
30,00c 
4 
8 
White 
1 95 
3 
'3 
100,000 
Fall 
9 
Piebald 
100 
3 
12 
500,000 
8 
10 
Piebald 
150 
3 
>5 
500,000 
8 
n 
White 
148 
3 
18 
300,000 
3 
12 
White 
«38 
4 
12 
600.000 
8 
<3 
White 
140 
4 
16 
200,000 
4 
H 
Piebald 
127 
3 
12 
200,000 
5 
>5 
Piebald 
104 
4 
11 
200,000 
IO 
16 
White 
58 
4 
12 
200,000 
8 
>7 
White 
62 
4 
8 
38,000 
Fall 
18 
White 
108 
2 
9 
2 million 
8 
■9 
Piebald 
137 
3 
10 
ii million 
7 
20 
Piebald 
182 
2 
8 
2 million 
8 
21 
Piebald 
>30 
3 
11 
ii million 
7 
22 
White 
iis 
2 
7 
it million 
6 
| 
Average ... 
780,000 
Remarks 
(7 to 8 divisions in 
next 24 hours) 
(10 divisions in next 
24 hours) 
Pregnant 
Pregnant 
See Chart 2 
Bll 
