158 MILK AND THE PUBLIC HEALTH CHAP. 



of epidemic diarrhoea from the administrative aspect are 

 satisfied as to its case -to -case infeetivity, at least in some 

 cases. Two examples may be mentioned. Epidemic diarrhoea 

 has been a voluntary notifiable disease in Woolwich since 

 1905. Dr. Sidney Davies, the medical officer of health, 

 remarks in a valuable special report on this disease in 1908: 

 " From the information obtained by the writer and the 

 sanitary inspectors, there can be no doubt that the infection 

 spreads from person to person in a family." By means of 

 spot maps it was shown that there was a very marked group- 

 ing of cases. 



Sandilands l brought forward evidence that certain fatal 

 forms of summer diarrhoea are communicable. He remarks, 

 however 



. . . nevertheless communicability is by no means a conspicuous 

 feature of epidemic diarrhoea in every case. Thus in 19 out of 

 35 tenement houses in Kensington where deaths were registered as 

 due to diarrhoea, no other cases occurred. Again in 25 out of 35 

 fatal cases of diarrhoea, no source of infection was found in the 

 families occupying the houses where these patients died. And 

 lastly, in 22 families containing young children fatal diarrhoea 

 occurred, and yet in these families 44- parents and 53 children 

 were intimately exposed to infection without falling ill. In 5 

 hospitals there is no evidence of the spread of diarrhoea from 

 patient to patient, and the sum of the evidence suggests that 

 diarrhoea is not more infectious than typhoid fever, and is not 

 conveyed except by the same channels. 



In regard to the means by which the bacterial infection is 

 transmitted from case to case the house fly has been suspect 

 for many years, and the evidence implicating flies steadily 

 grows in convincingness. The recent contribution by Niven 2 

 upon " Summer Diarrhoea and Enteric Fever " may be re- 

 commended as a valuable epidemiological study of this 

 relationship. 



In considering the relationship of milk and epidemic 

 diarrhoea, while the balance of evidence is decidedly in favour 

 of the view that the specific infection, which is the cause of 

 the disease, is domestic in origin rather than derived from 



1 Trans. Royal Society of Medicine, 1910, vol. iii. p. 95. 



2 Trans. Royal Society of Medicine, Epidemiological Section, 1910, vol. iii. 

 p. 131. 



