(161) 



402 , C. GORDON HEWITT. 



In two of: the experiments the flies were all dead on the 

 seventh and eighth days respectively, at a temperature of 

 14 C. At higher temperatures he found that flies died more 

 rapidly. He was able to show that the flies contained the 

 bacilli in a virulent condition for about two days after they 

 had fed on infected organs ; this, and the fact that the infected 

 flies can live for several days, are extremely important from 

 the practical standpoint, as indicating that flies should neither 

 be allowed to have access to the bodies or excreta of cases of 

 plagne, nor to the food. 



7. Miscellanea. 



There are on record a number of suggestions that flies may 

 be responsible for the dissemination of other diseases caused 

 by bacteria and other micro-organisms, and some account will 

 now be given of these and the experiments in support of such 

 beliefs. 



If flies have access to wounds of an inflammatory and sup- 

 purative nature they are liable to transport the Staphylo- 

 cocci to other spots. Buchanan (1907) allowed M. domestica 

 to walk over a film of Staphylococcus pyogenes aureus 

 from an abscess, and afterwards over agar ; a mixed growth 

 resulted, in which S. pyogenes aureus predominated. 

 Celli (I.e.) records experiments- which proved that S. 

 pyogenes aureus retains its virulence after passing 

 through the intestine of the fly. 



In the experiments carried out in 1907 by my friend Dr. 

 M. B. Arnold and myself, he chose B. prodigiosus for 

 the purposes of the experiment, as it is easily recognisable 

 and not likely to be accidentally introduced. Flies which had 

 just emerged from the pupae, and therefore not already con- 

 taminated with an extensive bacterial flora, were allowed to 

 walk over a film of the bacillus, after which they were con- 

 fined to sterile glass tubes. At varying periods they were 

 taken out and allowed to walk over the culture plates. Those 

 confined for over twelve hours retained the bacilli on their 



