E. E. Atkin and A. Bacot 
499 
while sterility was maintained; although in some instances slight pro¬ 
gress followed the addition (Experiment XIX, page 518), it soon ceased, 
the larvae eventually dying without attaining their full growth. 
Killed cultures of B. coli. 
In Experiment X a preliminary trial was made to ascertain if the 
larvae could be reared under sterile conditions upon a culture of B. coli 
killed by heat. No success followed, but young larvae hatched from 
unsterilized eggs made rapid progress in a control tube, this tube being 
of course infected by the larvae. Experiment XIV was a repetition 
on a larger scale; several tubes were prepared, but the eggs placed in 
these failed to hatch. A single newly hatched larva (the only one 
which could be spared at the moment) was transferred from another 
experiment to one of the tubes. It failed to make any progress during 
a month and died within a few hours of the inoculation of the tube at the 
end of this period. 
Sterile filtrate of B. coli. 
In Experiment XXIV a culture of B. coli killed by chloroform was 
added to tubes of sterile distilled water containing eggs; a number of 
these hatched and tube No. 12 remained sterile, although its fellow 
No. ] 1 became infected on the 11th day. None of the larvae in No. 12 
passed the first moult, while some of those in the infected tube had 
made considerable progress and were in the third instar. The larvae 
in tube No. 12 all died in the second skin, whereas in the infected tube 
the larvae were well grown before the food supply failed, two at least 
having attained their fourth (last larval) instar. 
Thinking that possibly the action of the heat used in killing the 
cultures of B. coli might have the effect of destroying its nutrition value 
for the mosquito, larvae, a number of trials were carried out with the 
sterile filtrate from broth cultures of B. coli. No success attended any 
of them, either in neat or diluted condition, nor did the addition of the 
filtrate to other sterile media in which larvae were living produce any 
effect, apart from the few cases in which sterility broke down at the 
period when the filtrate was added. (See Experiments XIX, XX and 
XXIII.) 
Living yeast and yeast extracts. 
See Experiments XVI, XVII and XXI; note also the conclusion of 
XXII, page 521, of XXIII and of XXIV and the conclusion of XXV. 
There is a break of similar character between the nutritive value of 
Parasitology ix 
33 
