184 
Development of Hook-ivorms 
XL Experiment with sand. 
In this series the material employed was fairly consistent and dry 
but not formed. Eggs were not numerous. Ten separate portions 
were used and treated with sand in various ways. 
1. Control. No sand. 
2. Covered with equal amount of dried sand. 
3. Covered with twice amount of dried sand. 
4. Thoroughly mixed with half the amount of dried sand. 
5. Thoroughly mixed with twice the amount of dried sand. 
6. Thoroughly mixed with equal the amount of dried sand. 
7. Covered with equal amount of sterilised sand. 
8. Covered with half amount of sterilised sand. 
9. Thoroughly mixed with equal amount of sterilised sand. 
10. Thoroughly mixed with half amount of sterilised sand. 
The results of cultures from these experiments are as follows: 
Nov. 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
1. 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
4- 
4- 
2. 
+ 
+ 
+ 
+ 
+ 
+ 
-1- 
+ 
+ 
4- 
4- 
3. 
-1- 
+ 
-1- 
+ 
+ 
- 
- 
- 
- 
- 
- 
4. 
+ 
-1- 
-t- 
+ 
-1- 
+ 
+ 
+ 
4- 
4- 
4- 
5. 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
4- 
4- 
4- 
6. 
+ 
+ 
+ 
+ 
+ 
+ 
-1- 
+ 
4- 
4- 
+ 
7. 
■f 
+ 
+ 
+ 
-1- 
-1- 
+ 
4- 
4- 
4- 
8. 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
4- 
4- 
4- 
9. 
+ 
+ 
+ 
+ 
+ 
-1- 
4- 
+ 
4- 
4- 
4- 
10. 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
4- 
4- 
4- 
From each of the cultures a considerable number of active and 
vigorous larvae were obtained. 
This series shows that sand, instead of having a deleterious influence 
on hook-worm eggs and larvae, has exactly the opposite effect, except 
when the faeces are thoroughly covered by the sand. The experiment, 
indeed, suggests that admixture with loose sand is an excellent method 
of rearing larvae for laboratory purposes. 
XII. Experiments on the effect of direct sunlight. 
As a preliminary to this series a small experiment was performed 
to test the effect of exposing the faecal material. Some faeces were 
freely exposed on a plate on the laboratory bench with doors and windows 
wide open during the day time. Another portion of faeces was exposed 
