122 INSECTS AND MAN 



pick out the enteric cases by the masses of flies they 

 attract. This was very noticeable at Modder River, for 

 at that time there were in many tents men with severe 

 sunstroke who resembled in some ways enteric (or typhoid) 

 patients; and it was remarkable to see the insects hover 

 round and settle on the enterics. The moment an enteric 

 patient put out his tongue a fly would settle on it. ... At 

 Bloemfontein the flies were a perfect pest; they were 

 everywhere, in and on every article of food. It is im- 

 possible not to regard them as important factors in the 

 dissemination of enteric fever. Our opinion is further 

 strengthened by the fact that enteric fever in South Africa 

 practically ceases every year in the cold weather ; and this 

 was the case at Bloemfontein." So clearly did the evidence 

 point to house flies as carriers of typhoid during the war, 

 that numerous investigators took up the matter and proved 

 conclusively that they were very efficient vectors of the 

 disease, even after a lapse of twenty-three days from the 

 day of infection. 



Another disease, with a higher death-rate than typhoid, 

 and, like typhoid, carried by house flies, is infantile diarrhoea, 

 or enteritis. " In London, during the year 1910, there died 

 of this disease 1,811 infants under two years of age; and 

 during 1911, which had a hot summer, the infantile death- 

 rate rose to even greater proportions. But in Bombay, 

 during 1910, 2,263 died, and in Paris this disease killed 

 1,152 infants ; in New York, 5,649 ; Chicago, 3,384 ; Rio de 

 Janeiro, 2,692." As a final example we read that : " During 

 the hot weather at Cairo in 1909 it killed 3,000 children 

 in less than two months." At the Lister Institute in 

 London, Dr Morgan carried out a series of researches on 

 this disease from 1905 to 1908, and succeeded in isolating 

 a germ which he called Morgan 1. Rats fed on the 

 bacillus died of enteritis; monkeys, too, subjected to the 

 same test, died exhibiting all the symptoms usual in 

 children. The researches were continued, but attention 



