W. Nicoll 
183 
IX. In this series material from the same patient as in the two 
foregoing experiments was used. Three portions were employed. 
The first was submerged to the depth of half an inch in rain water, 
the second to the depth of an inch and the third to the depth of one 
and a half inches. The experiment was continued for ten days and 
during all that time larvae were recovered from each of the three lots. 
It would thus appear that the submersion of infective faeces in water 
to the depth of even one and a half inches will not prevent the develop¬ 
ment of hook-worm larvae. 
X. The faecal material used in 
this experiment was firm 
decidedly moist. 
The salt was 
merely 
sprinkled on the surface. 
amounts used were as follows: 
Weight of 
W eight 
Percentage 
faeces 
of salt 
of salt 
1. 
3-4 g. 
0 
0 (control) 
o 
6-8 
0-2 g. 
2-9 % 
3. 
51 
0-4 
7-8 % 
4. 
4-5 
0-8 
17-7 % 
5. 
4-7 
1-6 
34-0 % 
6. 
3-4 
3-2 
94-1 % 
7. 
5-4 
6-4 
118-5% 
8. 
2-7 
12-8 
477-0 % 
This series is confirmatory of previous experiments. 
The results are tabulated below: 
Dec. 19 
20 
21 
22 
23 
24 
25 
26 
27 
1. 
+ 
+ 
+ 
-i- 
-1- 
+ 
+ 
+ 
2. 
+ 
+ 
- 
- 
- 
- 
- 
- 
3. 
+ 
- 
+ 
-1- 
- 
- 
- 
- 
4. 
+ 
- 
- 
- 
- 
5. 
- 
- 
- 
- 
- 
6. 
7. 
8. 
— 
— 
— 
— 
— 
, _ 
Here again it is evident that 17 % of salt sprinkled on the surface 
is not sufficient to kill hook-worm eggs within 24 hours, and that 8 % 
is not sufficient to kill in less than four days. In all the cultures larvae 
were very scanty, in most cases only one or two developing. 
