INFECTION FROM FLIES J;UKD IN INFECTED MATERIAL 225 



cage into which about 30 flies were liberated. Those flies died in 

 a day or two, but on August 26th, fourteen days later, a single fly 

 hatched and twelve flies emerged on the day following. The box 

 of earth was now replaced by a sterilised earthenware plate, and 

 the wire cage was changed for a bell-shaped mosquito net. The 

 flies were fed upon sugar and water. On August 26th one fly, 

 a day old, was chloroformed and transfixed with a red-hot needle: 

 its body was flamed (i.e. singed) and it was put into a bottle of 

 sterile salt solution. After shaking up, 1 c.c. of this solution was 

 put into McConkey broth which remained unchanged for 48 hours. 

 The fly was then crushed with a sterile glass rod and a drop 

 plated : this gave B. typhosus. On August 27th four other flies 

 were similarly treated ; the control experiment in McConkey was 

 negative but B. typhosus was obtained from the crushed flies. 



Similar results were obtained on September 8rd from two six- 

 day old flies and on September 6th from two nine-da}' old flies 

 treated in the same manner. On September 10th two flies, thirteen 

 days old, were placed in a sterile bottle for 24 hours and then 

 removed. The bottle was washed out with salt solution, and from 

 this B. typliosus was recovered. The two flies were then crushed 

 in salt solution, not having been flamed, and B. typhosus was 

 obtained. On September 13th a sixteen-day old fly was placed in 

 a sterile bottle for half an hour and then removed ; two drops of 

 excrement were visible and from sterile salt solution which was 

 added B. typhosus was obtained. This fly was flamed and crushed 

 and the bacillus was recovered. B. typhosus was not recovered 

 from another sixteen-day old fly similarly treated. 



A second series of experiments was carried out with the faeces 

 of a man suffering from paratyphoid fever (B. paratypliosus A.), 

 the diagnosis having been made by a blood culture. 



On August 22nd two ounces of liquid faeces infected with 

 B. paratyphosus A. were put into a box of earth and about thirty 

 flies were allowed to feed on it, etc. In a day or two they died 

 owing to the absence of water. On September 1st one fly hatched 

 out; on September 3rd, 12 flies were seen, and on that date the 

 earth was replaced by a sterile plate as in the previous experiments. 

 On September 1st one fly, one day old, was examined as before: 

 the McConkey broth control was negative and after being flamed 

 n. H.-F. 15 



