KONG, 5 Roberg: Bacterial Infections 325 
larvee were washed for five minutes in a 5 per cent solution of 
lysol. The larve were then washed three times in sterile salt 
solution and placed in Dunham’s peptone solution, after which 
they were crushed with a sterile glass rod. This material was 
incubated for twenty-four hours and streaked on Dieudonné’s 
medium. Growths of cholera vibrios were looked for. 
Three attempts to find vibrios in the intestines of 6-day-old 
larvee failed by this method. It was believed that in killing the 
surface vibrios with 5 per cent lysol sufficient liquid was ingested 
by the larve to kill the vibrios contained in the gut. To pre- 
clude any possibility of lysol entering the larval interior, the 
larve were sealed by applying a red-hot platinum point to the 
anal extremities, thus searing and closing the openings. Larve 
treated in this manner and washed in lysol also did not reveal 
the presence of any cholera vibrios. Failing to find vibrios 
within the larve, the agar-slant growth was examined for vibrios - 
and found to contain none, but did possess other contaminating 
organisms. 
To keep larve alive on a medium containing cholera vibrios 
until emergence of the adults occurred, it was found necessary 
to obtain a medium as free as possible from putrefying material; 
to use larve of an age which would soon pupate; and repeatedly 
to drench the sterile sand with 24-hour-old cholera broth cultures. 
This method is outlined in series III. In this series the cholera 
vibrios were identified by smears stained with Sterling’s gentian 
violet, by the characteristic growth on Dieudonné’s medium, by 
typical motility in hanging-drop preparations, and by agglutina- 
tion of the vibrios in hanging drops by the addition of cholera- 
immune serum. 
In series IV experiments were performed to determine 
whether cholera vibrios are harbored in the intestinal tract of 
flies which have been fed upon media containing vibrios, and 
the length of time they remain infective; if vibrios adhere to 
the surface of the body; and how long they remain infective. 
In performing these experiments it was necessary to use 
extreme care in handling the minute flies which were infected 
with cholera vibrios to prevent their escape. Under ordinary 
circumstances they can be caught with a forceps as they attempt 
to escape when the lid is raised from the vessel containing them. 
Before cholera-infected flies were handled, various methods 
were tried in order to find a means whereby it would be im- 
possible for them to escape. The most satisfactory means was 
the employment of a bent glass tube which served as a passage- 
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