74 
Experiments ivith Flies 
externally. They were then placed in 10 7o formalin for four to 
five minutes. Thereafter they were removed one by one to a tube of 
sterile broth and shaken up. From this tube they were transferred to 
a second broth tube and shaken. Finally from this second tube each 
pupa was removed to an agar slope and mashed up with a strong 
platinum loop. The two broth tubes and the series of agar slopes were 
then incubated at 37° C. Next day both the broth tubes were sterile 
but all the agar slopes showed abundant groiuth in which B. pyocyaneus 
was present. After 48 hours the broth tubes were still sterile but on 
the third day one broth tube (the second) showed growth. This slight 
discrepancy, however, in no way invalidates the general conclusion 
arrived at by Mr Bacot that the pupal interior may become heavily 
infected by organisms taken up during the larval stage. By further 
improvements in technique it may be possible to eliminate entirely any 
growth-effects before the final mashing-up process*. 
EDITORIAL NOTE. 
Dr Graham-Smith, who has been carrying out investigations for the 
Local Government Board, has obtained some very interesting results. 
Blow"-fly {Galliiihora erythrocephala) maggots were fed on meat 
infected with the spores of B. anthracis. When full fed the maggots 
were transferred to clean cages in which they pupated. The flies 
emerged about three weeks after the larvae had fed on the infected 
meat. Cultures were made from the organs of 51 of those flies, in some 
cases shortly after emerging, and in some cases when the flies were 
a few days old. B. anthracis was obtained from 26 flies. B. anthracis 
was also obtained from agar plates on which the flies had walked, from 
faeces deposited by them, and from syrup on which they were allowed 
to feed. Several of the cultures obtained were proved to be virulent. 
These investigations will shortly be published in Reports to the 
Local Government Board on Public Health and Medical Subjects. 
G. H. F. N. 
1 Since this was written I have devised a simple but efficient method of examining the 
bacterial content of the pupal interior in iV. domestica. The pupa is held lightly between 
the left thumb and forefinger so that its blunt extremity is free. With a small searing- 
iron this extremity is seared and at the same time flattened. It is then pierced by a fine 
capillary pipette controlled by a rubber teat. The pupal contents are stirred up by the 
extremity of the pipette and finally drawn up into the tube whence they are immediately 
squirted on to plates. The whole process takes less than a minute to perform. 
Kecently I have been successful in isolating B. typhosus from pupae the larvae of which 
have fed on this organism. The experiments will be pubhshed shortly. 
