520 
Stegomyia fasciata 
After ]20 hours. The larvae in all the starred (infected) tubes continued to grow 
rapidly: in the filtrate tube in which a mould appeared, all the eggs hatched but 
the larvae made no progress. 
Films from the filtrate tubes in which sterihty broke down stained by Gram’s 
method showed a mixed infection of bacteria other than B. coli. One tube showed 
sporing forms. The results were consistent with the explanation that the tubes 
were infected by organisms on the eggs, some of which had escaped the sterilizing 
process. 
Of the two peptone water tubes all the eggs in one tube hatched; a mould was 
noticed developing in the tube. The larvae made little if any progress during a 
period of 20 days, the mould gradually increasing at the surface of the fluid. The 
larvae were all dead within a month of hatching. 1 c.c. of the sterile filtrate of 
B. coli was added to the remaining peptone water tube and the two tubes of distibed 
water. Within 4 days all the eggs hatched in the peptone water tube, but it was 
evident that sterility had broken down. The larvae made rapid progress, but 
failed in their race with the bacteria—the fluid in the tube becoming very foul—and 
the larvae died. 
Sterility also broke down in the two tubes of distilled water, to which the filtrate 
was added. It is quite possible that it had broken down at the time when the 
eggs began to hatch, but as the tube was not tested the fact was not apparent until 
the filtrate was added. The larvae made rapid progress at first, but it soon appeared 
that they had exhausted the food supply as, although they continued healthy, no 
progress was made. The larvae gradually died off—a few survivors lingered on 
until the 88th day; they were then small and undersized in the third or fourth 
instar. Moulds were developing in both tubes and the death of the larvae followed 
in a few days. Concerning the filtrate tubes to which precipitated white of egg and 
treated milk were added nothing of interest remains to be said; all were infected 
with a species of bacterium that required cool conditions—60° to 65° F.—for its 
favourable development. The larvae grew rapidly at first but slowed down after 
a few days; after the 8th day they were still in the third instar. Those in the tube 
to which milk was added attamed the foxirth instar by the 12th day and then died. 
The larvae in one of the white of egg and filtrate tubes developed slowly and 2 
adults were reared within a month, but a mould had developed in the tube, and the 
remaining larva died. In the other tube a mould also developed and all died as 
larvae. 
3 % Yeast extract solution. Nos. 106 and 107. No larvae hatched within 
96 hours, but one was out in each tube withiq 120 hours; these larvae died within 
2 or 3 days. In one tube no more eggs hatched within 10 days; in the other a few 
larvae emerged and died. On the 12th day both tubes were inoculated from a cul¬ 
ture of a yeast; the eggs hatched during the night, in one tube they all died, but in 
the other a few of the larvae made rapid progress. Three A specimens were reared 
within 18 days of the inoculation and three 5$ followed a week or so later. 
2% Yeast extract solution with charcoal. One tube; within 24 hours 6 or 7 
larvae had hatched, the larvae making shght if any progress within 3 days of hatch¬ 
ing; within the next few days moulds commenced to grow. By the 7th day after 
hatching a few larvae had passed their first moult. Some of the larvae attained to 
the fourth instar within 20 days of hatching, but the growth of moulds had made 
