TUBERCULOSIS 



177 



Experiments xvitJi B. tuberculosis {Cultitre). 



" A large number of freshly-caught flies were allowed to feed on an emulsion of a 

 culture of human tubercle bacilli in syrup. After feeding, the flies were transferred to 

 a clean cage and fed daily on syrup. After varying intervals of time flies were caught 

 and dissected. Smear preparations were made from the crop and intestinal contents 

 and stained in the usual way for tubercle bacilli. Smears were also made from vomit 

 and faecal material and stained in the same way. Each of the preparations was very 

 carefully examined for tubercle bacilli by two observers." 



TABLE 24. SJioiving the results of an experiment ivith 

 a eulture of B. tubereulosis. 



Time after 

 infection 



[7 ho 



58 

 78 



96 



days 



14 



16 



No. of 



fly 



13 

 14 

 i.s 

 16 



17 

 18 



19 



20 



25 

 24 

 25 

 26 

 27 

 28 

 29 



30 

 31 



Crop 



+ 

 + 

 + 

 + 

 + 

 + 

 + 



(many) 



(few) 



+ 



+ (many) 



+ (several) 



4- 



4- 



4- (8 found) 



+ (2 „ ) 



4- (several) 



o 



4- (several) 



4- 



4- (2 found) 



4- (few) 



4- (i clump) 



4- (2 found) 



o 



Faeces 



4- in 6 out of 6 samples 

 4- in 3 out of 3 samples 



also in vomit 

 4- in 5 out of 6 samples 



4- in 3 out of 7 samples 



4- only I tubercle bacillus found 

 in several samples 



4- several 



4- I tubercle bacillus found 



4- 3 tubercle bacilli in 2 samples 



I tubercle bacillus found 



" These experiments show that, under experimental conditions, tubercle bacilli, 

 derived from a culture, may be present in the crop for three days. In the intestine, 

 however, they may be found for much longer periods, being present in considerable 

 numbers for at least 6 days. Subsequently their numbers diminish, but they may be 

 discovered by careful search for 12 days or even longer. In the faeces they are 

 numerous up to the 5th day, and occasional specimens may be found in frecal material 



G.-S. 12 



