(163) 



404 C. GORDON HEWITT. 



appendages and transferred them subsequently to the culture 

 media, but they were not recovered from those flies which 

 were kept in confinement for twenty-four hours ; a large 

 number of flies, however, were not used. 



Dr. Kerr, of Morocco, in a paper on " Some Prevalent 

 Diseases in Morocco/' read before the Glasgow Medico- 

 Chirurgical Society (December 7th, 1906), described epidemics 

 of Syphilis where, according to the author, the disease was 

 spread by flies which had been feeding upon the open sores 

 of a syphilitic patient. 



Howard (1909) calls attention to an important investigation 

 carried on by Esten and Mason (1908) on the role which flies 

 play in the carriage of bacteria to milk. The flies were caught 

 by means of a sterile net; they were then introduced into a 

 sterile bottle and shaken up in a known quantity of sterilised 

 water to wash the bacteria from their bodies and to simulate 

 the number of organisms that would come from a fly falling 

 into a quantity of milk. They summarised their results in the 

 table given on p. 403. 



From that table it will be seen that the numbers of 

 bacteria carried by a single fly may range from 550 to 

 6,600,000, while the average number was about 1,222,000. 

 Commenting on these results, the authors state that te early in 

 the fly-season the numbers of bacteria on flies are compara- 

 tively large. The place where flies live also determines 

 largely the numbers that they carry." From these results the 

 importance of keeping flies away from milk and other food 

 will readily be seen. 



VIII. FLIES AND INTESTINAL MYIASIS. 



The larvae of M. domestica and its allies are frequently 

 the cause of intestinal myiasis and diarrhoea in children. The 

 occurrence of the larvae in the human alimentary tract may be 

 accounted for in several ways. The flies may have deposited 

 the eggs on the lips or in the nostrils of the patient, or the 

 eggs may have been deposited on the food, subsequently 



