N. H. SWELLENGREBEL AND C. STRICKLAND 
381 
Day 
1 
2 
3 
4 
5 
6 
7 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
22 
23 
TABLE IV. (,Series II—I.) 
Infected lice 
With 
development 
0 
2 
0 
3 
0 
1 
3 
1 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
Without 
development 
6 
5 
1 
2 
2 
2 
4 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
0 
Uninfected 
lice 
1 
1 
0 
0 
0 
0 
0 
* 
2 
13 
- + 
9 
6 
6 
3 
3 
7 
6 
6 
6 
6 
3 
* The rat lost its trypanosomes between the 7th and 10th day. 
t Beginning of the control series. Last day on which developmental forms were found. 
the flea experiment. We have not indicated the dimensions of the 
different forms because they are the same as in the flea. 
The first changes are the same as those observed in the gut of the 
flea (Diagram XV). The blepharoplast wanders in the direction of the 
nucleus (Fig. 2) and the flagellate becomes more or less club-shaped 
(Figs. 3 and 4), but sometimes it remains thin (Fig. 5). 
Fig. 1. Agglomeration of two normal forms. G. 
Figs. 2—7. Nucleus and blepharoplast change their position. G. 
Figs. 8—9. Thick and slender crithidiae. G. 
