E. E. Atkin and A. Bacot 
521 
considerable progress by this time, and the larvae died within 2 or 3 days. 
Infection by bacteria in addition to the moulds was probable. 
Experiment XXII. 
Planned to contrast the effect, if any, on hatching of B. coli filtrate, beef broth 
and distDled water. It failed owing to the number of tubes in which sterility broke 
down. The experiment, however, affords evidence relative to the effect of the 
growth of moulds and the ability of the larvae to develop on a diet of living yeast 
cells. 
To each of 9 tubes containing 6 c.c. of sterile distUled water, was added 1 c.c. 
of filtrate from a culture of B. coli. 
To each of 6 tubes was added 1 c.c. of plain beef broth. 
Eight tubes contained the distilled water only. 
Eggs were sterilized by Method c and from 12 to 20 pipetted into each tube. 
After 24 hours. 
Filtrate and water. 7 of the tubes have at least 20 eggs; 2 have only 12 in them. 
In all the tubes there are one or more larvae swimming. In most of the tubes 
there are 5 or 6 larvae; in one 8 or 9, and in one a dozen. 
Beef broth. Four of the tubes had 12 to 18 eggs; two had at least 20 eggs in 
them. The hatchings were: 2:1:2:1:8:2. 
Distilled water. Six of the tubes had from 12 to 20 eggs; two had 20. The 
hatchings were: 1; 1: 0 : 0 : 0 : 2 ; 0 : 0. 
After 4 days. 
Filtrate and water. In one tube (No. 9) there was a bacterial growth; the water 
was cloudy; aU the eggs had hatched and the larvae showed vigorous progress. 
In aU the remaining tubes, though hatching was general, larval progress was not 
evident; there was no bacterial growth, but moulds had commenced to grow in 
the tubes. 
Beef broth and water. In two tubes (2 and 6) bacterial growth started; in two 
(1 and 5) moulds grew, while two (3 and 4) remained sterile. Hatching was general, 
but not complete in those tubes which were not infected by bacteria or moulds; 
larval growth was rapid only in those containing bacteria. 
Distilled water. In two of the tubes two or three eggs hatched; in three one 
hatched, while in three no larvae emerged. 
Subsequent history. 
Filtrate and water. Nine tubes numbered 1 to 9. 
No. 1 had a double infection of bacteria and moulds; one undersized d bred after 
35 or 40 days, remainder died. 
No. 2, white surface'moulds gradually increased, and the larvae gradually died 
off; 1 lived 60 days, and died in the third instar. 
No. 3, dark smface moulds grew gradually; 1 larva lived 53 days but died in 
the third instar. 
No. 4, grey surface moulds grew gradually; none of the larvae passed the 
second moult—all died within 50 days. 
