190 Insects and Disease. 



14th February, 1913. 



Chairman — Dr J. Maxwell Ross, Hon. V.P. 



The Part Played by Insects in the Propagation 

 of Disease. 



By J. C. Thomson, M.A., M.D., D.P.H., 

 Dip. in Tropical Medicine and Hygiene (Cantab.). 



[Dr Thomson, in a lucid and interesting manner, illus- 

 trated the importance of the part played by insects in the 

 transmission of disease by many examples. In some detail 

 he dealt with the transmitting insects of Malaria (the 

 Anopheles Mosquito), Elephantiasis (the Culex Mosquito), 

 Yellow Fever (Stegomyia fasciata), Sleeping Sickness (Tse- 

 tse Fly), Kala-azur, the black sickness (the Common Bed- 

 Bug), Relapsing Fever (Ticks, Body Louse, and possibly 

 Bed-Bug), Typhus Fever (lice), and the Bubonic Plague 

 (Pulex cheopsis), and dwelt on the remarkable success 

 attending the efforts to abolish Malaria and Yellow Fever by 

 the destruction of the transmitting agents. 



Special emphasis was laid upon certain facts relating 

 to the common house fly (Musca domestica), the lesser 

 house fly (Fannia canicularis), and the blue-black blow 

 fly (Calliphora erythrocephala), which have recently come 

 to light, and afforded conclusive evidence that the house 

 fly in all its species is a factor to be reckoned with in the 

 transmission of such diseases as infantile diarrhoea, typhoid 

 fever, tuberculosis, diphtheria, cholera, anthrax, and the 

 parasitic worms that infest the intestine. Most directly im- 

 portant was the relationship of the insect to infantile diarrhoea 

 and enteric fever. Epidemics of the former occur in this 

 country in late summer and early autumn, and the maximum 

 mortality coincides usually in the week in which the tempera- 

 ture recorded by the 4 feet earth thermometer attains its 

 mean weekly maximum, just when the warmth of the soil 

 favours free hatching-out and increased prevalence of flies. 



Dr Thomson recommended the improving of the sani- 

 tary condition of stables, the abolition of middens and open 



