February, '09] JOURNAL OF ECONOMIC ENTOMOLOGY 43 



diarrhoea developed. Sandilands, in the Journal of Hygiene states 

 that the great majority of eases of diarrhoea are due to the consump- 

 tion of infected food, and suggests that the seasonal incidence of 

 diarrhoea coincides with, and results from, the seasonal prevalence of 

 flies. Dr. Jackson records several epidemics of a malignant type 

 of dysenterj^ radiating from a single point and disappearing entirely 

 when proper disinfection of closets was enforced. 



The evil possibilities of the fly are by no means exhausted in the 

 above recital. It is well known that flies feed upon sputum. Ex- 

 periments by Lord recorded in the Boston Medical and Surgical 

 Journal show that flies may ingest tubercular sputum and ex- 

 crete tubercular bacilli, the virulence of which may last for at 

 least 15 days. He considers the danger of human infection from 

 this source to lie in the ingestion of fly specks on food, and suggests 

 that during the fly season great attention should be paid to the screen- 

 ing of rooms and hospital wards containing patients with tubercu- 

 losis and laboratories where tubercular material is examined. 



Nuttall considers that the evidence previously submitted proves 

 that the house-fly may carry about and deposit anthrax bacilli, though 

 there may be a question as to how generally flies are responsible for 

 the dissemination of this disease. Parke admits the possibilities of 

 flies distributing, in addition to those mentioned above, plague, tra- 

 choma, septicemia, erysipelas and leprosy. Furthermore, there are 

 those who would hold flies responsible for the more frequent new cases 

 which occur in a zone immediately surrounding the smallpox hos- 

 pital and which may be due either to the wafting out of infected 

 particles or their carriage by flies. The latter is considered the more 

 probable. Howe, according to the statement of Dr. Howard, has 

 demonstrated that the purulent conjunctivitis of the Egyptians is 

 spread by the house-fly. The experiments of Grassi show that the 

 eggs of Taenia, Trichocephalus and Oxyuris pass uninjured through 

 the alimentary tract of flies. 



A word respecting the dissemination of flies may not be out of place 

 'in this connnection. The experiments by Dr. L. 0. Howard several 

 years ago illustrated in a striking manner the possibilities of reducing 

 the number of flies by giving adequate treatment to accumulations 

 of manure in the vicinity. This is very satisfactory so far as reduc- 

 ing the annoyance caused by flies is concerned. There is a phase of 

 this question which has apparently received little consideration, 

 namely, the conveyance of flies by vehicles of one kind or another. 

 It only requires a little observation to convince one's self that the 

 butcher cart of the country is a very efficient carrier of flies, pre- 



