186 
Development of Hook-worniPi 
The results were as follows: 
1 2 3 4 5 6 7 
5 p.m. +- + - + + + 
6 p.m. +- + - + + + 
The experimental plates were then removed indoors and kept there 
for nearly two days. 
At 2 p.m. on the second day cultures were again made with the 
following results: 
123466789 10 
— — + + — + + + 
This experiment provides one or two rather interesting conclusions. 
It shows that hook-worm eggs can resist the effect of strong sunlight 
for over two hours when the faecal material is freely exposed either 
alone or surrounded by water. When, however, the material is exposed 
under glass to the direct rays of the sun, the eggs are all killed off within 
an hour whether there be water present or not. It seems very probable 
that this result is due to the heat concentrated within the covered glass 
dish. On the other hand in the case of the material placed in the 
shade the eggs in the covered specimen survived longer than those in 
the uncovered specimens. 
XIV. This series was similar to the last with certain modifications. 
The material used was solid and slightly moist. The procedure adopted 
was as follows; 
1. Part placed in covered glass dish 
2. Part placed in covered glass dish with water 
3. Part spread out thinly in covered dish 
4. Part spread out thinly in covered dish with water 
5. Part placed in open glass dish 
6. Part spread out thinly in open dish 
7. Part placed in open dish with water 
8. Part spread out thinly in open dish with water 
9-16. Duplicate series—exposed to sunlight 
17-24. Control series—kept in room 
The average shade temperature registered during the experiment 
was 83-2° F. with a wet bulb of 73-4° F. and a solar radiation up to 
1.30 p..iii. of 138-2°. Indoors the temperature was about 81-5° F. 
Exposed to 
direct sun- 
■ light from 
noon till 
1.30 p.m. 
