530 
Stegomyia fasciata 
The remaining tubes were infected with a j'east to see if any dormant eggs survived. 
Single eggs hatched in tubes No. 1 distilled water and No. 6 broth and filtrate. 
Further quantities of yeast cells were added to distilled water and filtrate tube 
No. 12 on the 204th day; the larva pupated on the 205th day and an adult was 
reared on the 208th day. 
Experiment XXIV. 
Planned to test further the effect of sterile cultures of bacteria and extracts of 
yeasts on dormant eggs. 
Twenty-four tubes each containing 8 c.c. of distilled water were sterdized and a 
number of sterile eggs varying from 20 to 50 were introduced. After 5 days the 
tubes were examined, and a selection made of those in which only a few eggs had 
hatched. 
The following were chosen; 
No. 
1, about 50 eggs, 6 hatched; aU the larvae dead. 
No. 
2 
>» 
25 
»> 
none 
99 
No. 
3 
>» 
40 
>* 
2 
„ all the larvae dead. 
No. 
4 
30 
»» 
1 
,, larva dead. 
No. 
5 
50 
4 
„ 1 larva hving. 
No. 
6 
45 
99 
3 
„ aU the larvae dead. 
No. 
7 
30 
99 
3 
„ 2 larvae living. 
No. 
8 
30 
99 
3 
,, aU the larvae dead. 
No. 
9 
25 
99 
none 
99 
No. 
10 
*> 
25 
99 
2 
„ aU the larvae dead. 
No. 
11 
»» 
40 
99 
2 
99 99 99 99 
No. 
12 
>> 
20 
99 
1 
„ larva dead. 
No. 13 
>> 
35 
99 
5 
„ 1 larva hving. 
No. 14 
30 
99 
4 
„ 2 larvae hving. 
Ten tubes were not used. 
The cultures or extracts used were as follows: 
Autolyzed extract of brewers’ yeast, B. coli. Staphylococcus aureus, sterilized by 
autoclaving. B. coli and 8. aureus, sterihzed by steaming. B. coli, killed by 
chloroform and a sterile filtrate of B. coli. This last w£ts several weeks old at the 
time of the experiment. 
All the media had been kept for 48 hours and sub-cultured to test for sterility 
before use; -5 c.c. = 6 % was added to each tube except in the case of the auto- 
lyzed yeast in which test -2 c.c. = 2-5 % was added to one tube and -5 c.c. = 6 % 
to the other. 
Autoclaved: 
No. of Tube 
Autolyzed yeast extract... No. 1, 2-5 % added 
No. 
2,6% 
99 
B. coli 
.No. 
3,6% 
99 
No. 
4. 6 % 
99 
S. aureus ... 
.No. 
5, 6 % 
99 
No. 
6, 6 % 
99 
Hatching commenced within 
5 minutes. 
Hatching commenced within 
5 minutes. 
No effect within 10 minutes. 
