FATE OF ORGANISMS EATEN BY LARVA 1 23 



(4) "In those cases in which B. dysoitericE (' Y ') was 

 successfully recovered from pupse, the colonies on the plate 

 were invariably fewer than those obtained from pup?e and 

 imagines after administration to the larva; of more adaptable 

 organisms such as ' Bac. A ' (Ledingham). 



(5) "A certain proportion of the pupee remained sterile, so 

 that the process of metamorphosis is undoubtedly accompanied 

 by a considerable destruction of the bacteria present in the larval 

 stage. 



(6) " The possibility of flies becoming infected from the 

 presence of pathogenic organisms in the breeding grounds of 

 the larvae may be considered as very remote." 



General Summary. 



The evidence hitherto published relating to the possibility 

 of the micro-organisms ingested by the larva; surviving in the 

 adult fly has been fully quoted because the subject is one of 

 great importance. Though it seems to have been proved that 

 the spores of B. antJiracis may survive, most observers agree 

 that such non-spore bearing pathogenic organisms as B. typhosus, 

 B. enteritidis and B. dysejitericB derived from cultures and added 

 to the food of the larvae are not present in the flies \vhich emerge, 

 except under very special and highly artificial conditions. Most 

 of these observers conclude from their experiments that the 

 possibility of flies becoming infected from the presence of 

 pathogenic organisms in the breeding ground of the larv^ may 

 be considered as remote. On the other hand Faichnie working 

 with uncidtivated B. typJiosiis and B. paratypJwsiis A stated 

 that he was able to isolate these organisms from the flies which 

 emerged. All the other investigators have failed to take into 

 account the possibility o{ adtivated bacillih&hdiwing in a different 

 manner to uncultivated bacilli. Faichnie's experiments are not 

 altogether conclusive since the experimental conditions were 

 such that the newly emerged flies might have re-infected them- 

 selves by feeding on the contaminated material. There is no 

 evidence in his paper that he separated the larva; which had fed 

 on infected material and examined the pupae and imagines 



