lOO 



DISTRIBUTION OF BACTERIA 



TABLE 9. Shoiving the results of expei'inients with living 

 flies allowed to zvalk over the surface of agar plates. 



No. of flies 



allowed to 



walk on plate 



Result 



About 600 colonies of B. prodigiosus 

 Numerous colonies of B. prodigiosus 



Several 



{d) Experiments on the infection of sugar. 



Flies were allowed to feed on syrup infected with B. pro- 

 digiosus for 15 minutes, and were then removed to fresh cages. 

 At various times one or two crystals of brown sugar were placed 

 in the cage and the flies allowed to suck them for some time. 

 The crystals were then taken out and dissolved in a drop of 

 water, and the solution sown on agar. The results of three 

 series of experiments of this kind are incorporated in the following 

 table : 



TABLE 10. SJiozving results of alloiving infected flics to 



feed on sugar. 

 Time after infection 

 when sugar given Results 



3 hours ... B. prodigiosus cvX'iw'AX^iX. Numerous colonies 



4 M ■•• ,> 

 4-5 „ 



5 .. ••• >» 

 5'25>. ■•• .. 



32 „ 



42 ,, 



46 „ 



56 „ 



66 ,, 



3 (lays 



4 1. 



5 >. 



6 ,, 



