182 
Development of Hook-worms 
It is evident from the above table that the presence of a moderate 
amount of water encouraged the development of the hook-worm eggs 
and larvae, while an amount sufficient to cover the faecal material to 
a depth of half an inch is not prejudicial. The fact, however, that the 
faeces floated to the surface in this particular experiment somewhat 
lowered its value. 
With regard to the salt solutions it is evident that 10 % saline is 
not sufficient to kill the eggs within three days, while 5 % cannot be 
depended on in less than eleven days. Below that strength salt solution 
has apparently no more effect than rain water. 
It must be remarked, however, that the larvae obtained in these 
experiments developed- much more slowly than those from the normal 
control. The average hatching time in the control was a little over 
one day. In the cultures from rain water it was about two days, 
while in those from salt solution it was generally nearly three days or 
over. 
The control sample became dried up on the seventh day and had 
to be moistened every second day. 
VJII. In this series faecal material from the same patient as in 
the previous experiment was employed. The quantities used were: 
Weight of 
faeces 
Weight 
of Balt 
Percentage 
of salt 
1. 
3-0 g. 
0-7 g. 
23% 
*> 
31 
0-6 
20% 
3. 
3-6 
0-5 
14 
/O 
4. 
3-3 
0-3 • 
9% 
5. 
3-9 
0-2 
5% 
6. 
4-3 
0 
0 (control) 
The material was of Arm consistency and fairly dry. The salt was 
mixed up 
•with 
it. 
The results 
are 
as follows: 
Nov. 1 
1. 
2. 
2 
3 
4 6 6 
7 8 
9 10 11 12 13 14 
+ 
3. 
-1- 
4. 
+ 
+ 
+ - - 
5. 
•f 
+ 
-1- -t- + 
+ + 
------ 
6. 
+ 
+ 
+ - - 
+ 
These results are in agreement with those obtained in previous 
experiments. *■ 
