338 
Races of Entamoeba histolytica 
in the following table (Table V). The measurements, as before, are given 
in units of the micrometer scale. 
Table V. 
Dimensions of cysts (in balsam) 
Case No. 
3-0 
3-5 
4-0 
4-5 
5-0 
5-5 
6-0 
6-5 
7-0 
7-5 
8-0 
8-5 
9-0 
E. 130 ... 
3 
7 
131 
78 
19 
4 
22 
40 
123 
39 
23 
10 
1 
E. 79 
2 
52 
59 
89 
28 
24 
44 
68 
63 
56 
12 
3 
H. 11 
— 
— 
7 
16 
12 
3 
35 
86 
160 
97 
64 
18 
2 
The outstanding feature of these curves is that they all possess two 
apices. Case E. 130 (Fig. 5) is perhaps the most striking. The distribu¬ 
tion of the cysts around the two modes (6p, and 10-5p,) is remarkably 
E.79 
symmetrical; and the entire curve may be compared with the two 
separate curves, taken together, from Cases H. 8 and E. 42 (shown in 
Fig. 4). The latter represented two different strains of E. histolytica — 
from two different patients—and it can hardly be doubted that a 
similar interpretation must be applied to the former (Case E. 130): for 
here we obviously have an infection—in this case of the same patient— 
with two different strains simultaneously, the cysts belonging to each 
strain being present in approximately equal numbers. The other two 
cases (E. 79 and H. 11) give less symmetrical curves, but are obviously 
capable of like interpretation. Case H. 11, for example (see Fig. 7), 
clearly represents a double infection in which the number of cysts belong¬ 
ing to one strain (that producing large-sized cysts) greatly exceeds that 
of the other (that producing small cysts). 
