DISTRIBUTION OF BACTERIA 



lOI 



From these experiments it appears that flies are able to 

 infect sugar for at least two days after feeding on an emulsion 

 oi B. prodigiosus in syrup. 



{e) The period during which infected /cecal material is 

 deposited. 



Several experiments to ascertain the period during which 

 infected faecal material may be deposited were conducted in the 

 following way. Flies were allowed to feed on syrup infected 

 with B. prodigiosus for 30 minutes, and then transferred to fresh 

 cages. xA.t various intervals they were again transferred to fresh 

 cages, and the faeces left in the old cages emulsified in water, 

 and the emulsions sown on agar. 



TABLE II. Shoiving the period during luhich infected fizces 



are deposited. 



Time after infection 

 when fteces collected 



2 hours 

 3 

 4 

 6 

 8 



10 

 l<S 



26 



48 



3 "^^ays 

 4 



B. prodi 



Result 

 ^iosus cultivated from 3 out of 4 deposits 



,, from 3 out of 5 deposits 



,, from 3 out of 5 deposits 

 ,, from 6 out of 8 deposits 



not cultivated from 5 deposits 



cultivated from 3 out of 6 deposits 



not cultivated from 5 deposits 



cultivated from 3 out of 7 deposits 



not cultivated 



cultivated. One colony in cultures from 8 deposits 



not cultivated 



These experiments show that heavily infected faecal material 

 may be deposited for at least two days after infection. 



