I/O SUMMER DIARRHCEA 



which the patients were infected with INForgan's bacillus. Either all the flies wtre 

 dead on arrival, or only a few were still alive. Deducting these cases we find that 

 this type of bacillus was found in flies from lo (38%) out of 26 of these houses. 

 Further, it is of importance to note that no bacilli of this type were isolated from flies 

 received after September i6th. Previous to that date satisfactory cultures from flies 

 from 24 infected houses were made and Morgan's bacillus isolated from flies from 

 10 (42 "/.,)■ 



Satisfactory cultures were obtained from flies received from 11 of the 13 non- 

 Morgan infected houses mentioned. Flies from one (q^/o) yielded a bacillus of the 

 Morgan type (Ga 6). Flies from three houses yielded bacilli of the types discovered 

 by Dr Lewis in the f;eces of the patients. 



Flies from four other Birmingham houses, in which cases of epidemic diarrhoea 

 had occurred, were examined. All the flies from two houses were dead on arrival, 

 but from a fly from one (50 "/o) of the remaining two batches Morgan's bacillus (Ga 8) 

 was isolated. 



Batches of flies (series B) from seven houses in Cambridge, in which cases of 

 epidemic diarrhoea had occurred, were examined between i8th and 31st August. 

 Morgan's bacillus (Ga 8) was isolated from the flies from three (43 "/o) houses. 

 Batches of flies (Series C) from the diarrhoea infected farm house near Cambriilge 

 were examined on six occasions. Morgan's bacillus was isolated from the flies 

 of three batches. 



On the other hand 10 batches of flies from Birmingham houses (series D) in which 

 no cases of epidemic diarrhcea had occurred, were examined. Cultures were made 

 from 147 flies, but from only one fly was a bacillus of the Morgan type (Ga6) isolated. 

 From four Cambridge houses (series E, F, G, H), in which no cases of diarrhoea had 

 occurred, 452 flies were examined. From three flies bacilli of this type (Ga 5, Ga 7, 

 Ga 8) were isolated (o'6*^^Vo)- 



Taking the result.s of all the examinations made, it is found 

 that bacilli of the Morgan type (86°/o of which belong to the 

 variety Ga 8) were isolated from 5-3 "/o of flies (32 out of 642 flies) 

 from diarrhoea infected houses and from 0"6°/o of flies (4 out of 

 600) from houses in which no cases of diarrhoea had occurred. 



Taking into consideration the following facts — that in tabu- 

 lating the results cultures from dead flies which seldom }'ielded 

 non-lactose fermenting bacilli are included, that the patients, in 

 some of the houses from which the flies were sent, were convales- 

 cent, that from most of the infected houses only a single batch 

 of flies was received, that only a small number of flies from each 

 batch was examined and further that only three colonies of 

 non-lactose fermenting bacilli were isolated from each infected 

 fly — the results are interesting and suggestive. They show that 

 flies obtained from diarrhoea infected houses in Birmingham and 

 in Cambridge during the summer of 191 1 harboured Morgan's 

 bacillus at least nine times as often as flies from non-infected 



