434 
(/?) 7. gambiense 
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 
Remark 
*3 
Piebald 
'73 
6 
•9 
2 million 
8 
See Chart ; 
24 
White! 
‘65 
5 
'5 
500,000 
10 
25 
Piebald 
'55 
3 
'3 
2 million 
3 
26 
White 
150 
6 
'5 
1 so,000 
8 
2 7 
White 
"3 
5 
* 5 
60,000 
7 
28 
White 
101 
5 
'7 
60,000 
3 
2 9 
Piebald 
230 
2 
11 
1 million 
3 
3 o 
Piebald 
'25 
8 
>6 
5 00,000 
8 
31 
Piebald 
TOO 
4 
12 
85.000 
2 
32 
Piebald 
'55 
2 
11 
1,500,000 
3 
Not very resistar: 
33 
White 
40 
2 
8 
100,000 
8 
Young 
_ 1 
\vcragc ... 
723,000 
From the foregoing tables it follows: — 
(1) That the average incubation period* in the case of 
7 . rhodesiense was 2‘Q days, whereas the average incubation period 
in the case of T. gambiense was 4'4 days. 
(2) 1 he average life of rats inoculated with T. rhodesiense was 
11 3 days, whereas the life of rats infected with T. gambiense was 
13 8 days. 
These inferences are legitimate, for the average weight of the 
rats inoculated with T. rhodesiense was 138*8 grams, whereas the 
average weight of those inoculated with T. gambiense was 13/ 
grams. Also the numbers of trypanosomes inoculated were 
nearly the same in the two strains, averaging 780,000 and 723,00c 
respectively. 
\ 3 ^ On comparing the number of divisions of parasites 
occurring in the first twenty-four hours in both strains, we find 
that it was approximately the same, namely, six divisions on the 
a\ciage, and varied in each case from two to ten divisions, most 
frequently being eight. 
(4) There is also a shorter period between the crests of the 
waves in the graphs denoting the number of trypanosomes in 
parasitS’iitn^r We . mcan , the interval fa days) from the moment of inoculation of the 
peripheral blood of°host ^ trv P anosomes are first found in one cubic millimetre of the 
