E. E. Atkin and A. Bacot 
491 
the 39th day was inoculated from a living culture of B. coli. The dor¬ 
mant eggs hatched within a few hours. A similar result followed the 
inoculation of a tube of peptone broth in the same experiment with 
B. coli, the eggs hatching within a few hours of the introduction of the 
bacteria after they had lain dormant for 39 days. 
In Experiment XXIII several instances occur. In a sterile tube of 
distilled water containing 1 part in 6 of a filtrate from a broth culture 
of B. coli, eggs that had been dormant for 28 days hatched within 12 
hours after the tube had been inoculated from a living culture of B. coli. 
In a sterile tube of distilled water containing 1 portion in 6 of beef 
broth the eggs hatched on the 50th day within a few hours after the 
inoculation of the tube with B. coli. A similar tube was infected on 
the 60th day with a small quantity of a broth culture of B. coli ; the 
eggs hatched within 10 to 15 minutes. On the 100th day of the experi¬ 
ment eggs that had been lying dormant in a tube of sterile distilled 
water hatched within 10 minutes of the addition of 3 % of a living 
culture of B. coli. 
In a duplicate tube the addition of 3 % of a recently killed culture 
of B. coli caused 1 egg to hatch out of 11 within 15 to 20 minutes, but 
no more hatched within an hour and a half, when the addition of 3 % 
of a living broth culture of B. coli caused 6 eggs out of the remaining 
10 to hatch within 15 minutes. The remaining eggs did not hatch at 
all and were most probably dead. 
Unidentified bacteria. 
Cases in which hatching followed the breakdown of sterility were 
frequent; instances will be found in most of the experiments, in many 
cases two or more tubes containing different media being affected. 
Although the species of bacteria were not identified it was clear from 
their behaviour when sub-crdtured that they were of different kinds; 
some developed spores, while at least three different species were 
present, which would only grow at a temperature below 80° F. 
Apparently any species of living bacterium may act as a stimulus 
though there is some evidence that certain species act more quickly 
than others (see Experiment XXIV). It is also significant that hatch¬ 
ing only follows inoculation with a small quantity on a loop after 
several hours, whereas if as large a quantity as 2 % or 3 % of a broth 
culture is added, hatching follows as a rule within 15 minutes. There 
is also some evidence which suggests that fresh cultures are more 
effective than older ones of two or three weeks’ age. 
