502 
Stegomyia fasciata 
EXPERIMENTS WITH UNSTERILIZED EGGS. 
Ejfect of foul water charged with bacteria. 
Experiment I. 
100 c.c. of tap water was put into each of two glass pans. The water tempera¬ 
ture during the course of this experiment was about 65° to 67° F. 
A batch of about 350 eggs laid on filter paper three weeks previously and allowed 
to dry after incubation, but stored in a moderately humid atmosphere, was divided 
into two lots, approximately haK being immersed in each pan. 
To the water in one pan [A) was added 3 c.c. of sewage water (a fragment of 
human faeces was placed in water and allowed to incubate for 48 hours at 80° F.); 
to the water in the other pan (B) nothing was added. 
After 1 hour in A 
4 
„ „ B 
After 4 hours in A 
10 
„ „ B 
After 20 hours in A 
113 
>, B 
6 
After 70 hours in A 
9 
?> »> B 
36 
eggs had hatched, 
no eggs had hatched, 
additional eggs had hatched, 
no eggs had hatched, 
additional eggs had hatched, 
eggs had hatched, 
additional eggs had hatched. 
>» *9 
Total 136, 
Total 42. 
Experiment II. 
The experiment was repeated, using water in which horse dung had been steeped 
for the stimulating fluid. The quantities and other arrangements were similar to 
those in Experiment I, 3 c.c. of the contaminated water was added to pan A at the 
start, but none to pan B. 
After 18 hours in A 148 eggs had hatched. 
?> »» ^ If )) 
3 c.c. of the contaminated water was then added to pan B. At the expiration 
of another 18 hours 159 additional eggs had hatched in pan B. The size of these 
larvae suggested that they must have hatched within an hour or two of the addition 
of the manure water. 
Experiment III. 
Contrasted effect of alkali and water charged with bacteria. 
Temperature 75° F. 
Into each of 4 pans containing 100 c.c. of tap water was placed -007 gr. of incu¬ 
bated eggs of S. fasciata (the number would be about 200 or 300 eggs). The pans 
were kept all night at 75° F. Pan (1) formed a control. To pan (2) was added 
a solution of washing soda, producing an equivalent of 1 in 1000 in the pan; to 
pan (3) sufficient ammonia was added to produce 1 in 1000. To pan (4) about 5 c.c. 
of peptone broth from an experimental tube in which a bacterial infection caused 
the eggs to hatch. 
