E. E. Atkin and A. Bacot 
503 
After 6 hours (No. 2) Soda, showed a few larvae out. 
„ (No. 3) Ammonia, showed a few larvae out 
„ (No. 4) Contaminated, many. 
„ (No. 1) Control, only one or two. 
To the control pan about 2 e.c. of an infusion from horse dung was added, and 
the pans were left all night. 
18 hours later (No. 2) Soda, showed a small number out. 
„ (No. 3) Ammonia, about the same number out. 
,, (No. 4) Contaminated, swarms. 
,, (No. 1) Control, after the addition of the infusion of horse 
manure many more had hatched than in either the 
soda or the ammonia containers, but not so many 
as in the contaminated pan. 
10 c.c. of water from pan (No. 4) was added to pans Nos. 2 and 3. An examina¬ 
tion 6 hours later showed that the numbers of larvae had increased by one-third to 
a half, the freshly emerged larvae being easily distinguished from those which had 
hatched some hours previously, by their pointed conical heads. 
Experiment IV. With sterilized eggs. 
Contrasted effect of alkali, filtrate of B. coli and living B. coli. 
Tubes taken from Experiment XXI (see page 519). 
A batch of eggs was sterihzed by Method b and from 12 to 20 were pipetted 
into a number of tubes containing 10 c.c. of sterile distilled water and one (No. 5) 
containing sterile filtrate of B. coli. After 20 hours at 75° F. the tubes were 
examined and four containing distilled water were selected in which only one or two 
eggs had hatched, the idea being to use resistant eggs which did not respond without 
stimuli. 
In tube No. 1, 2 eggs had hatched (1 larva was dead). 
„ No. 2, 2 
„ No. 3, 2 
,, No. 4, 1 ,, ,, 
,, No. 5,0 ,, ,, 
To No. 1 was added 1 c.c. of water in which horse dung had 
been steeped for 48 hours at-37° C. .= 10 %. 
„ No. 2 was added 1 c.c. of a sterile filtrate of a B. coli culture = 10 %. 
„ No. 3 „ 1 c.c. of a 1 % solution of washing soda = 1-1000. 
„ No. 4 „ 1 c.c. of a 1 % solution of -880 ammonia = 1-1000. 
No. 6, a tube of filtrates of B. coli culture, was inoculated 
from a living culture of B. coli. 
Result after 1 hour: 
Increase in hatching 
No. 1, more than 12 larvae out ... . 10 or over 
No. 2, 4 larvae out 
No. 3, 3 „ 
No. 4, 1 
No. 5, 0 „ 
2 
1 
0 
0 
