214 BACTERIA IN MILK AND MILK PRODUCTS 



during a limited time. There was no antecedent throat illness, and 

 no school infection or contact contagion traceable. The houses were 

 sanitarily good, and had a good water supply. There was but one 

 thing common to most of the cases, and this was the milk supply. 

 It was found that within the area of the greatest prevalence of 

 throat illness, about one-fifth of the households were supplied by a 

 common milk supply. The incidence of the disease fell, actually and 

 relatively, upon consumers of the suspected milk. 



Inquiry into the milk supply elicited no evidence of human 

 disease pollution, nor contamination by water or air. Nor was there 

 any definite disease of cows present at the time as far as could be 

 judged. But by a process of exclusion, Mr Power suggested that 

 " there may have been risk of specific fouling of milk by particular 

 cows suffering, whether recognised or not, from specific disease." 



Since that time there have been some 30 outbreaks of milk-borne 

 diphtheria. In most cases the milk appears to have been infected 

 directly by persons suffering from the disease, recognised or un- 

 recognised. 



Milk-borne Scarlet Fever 



There are some seventy milk-borne epidemics of scarlet fever on 

 record, and yet comparatively little is known as to the bacteriology 

 of the disease (see p. 296). In almost all the outbreaks which have 

 occurred there is evidence, more or less conclusive, that persons 

 suffering from scarlet fever have been concerned in milking or in the 

 distribution of milk. But in 1882 Mr W. H. Power, in investigating 

 an outbreak of milk-borne scarlet fever in North London, came to the 

 conclusion that the cow had been the exciting cause of the epidemic, 

 and was suffering from some diseased condition which could convey 

 to the milk the virus of scarlet fever.* In 1885 occurred the 

 " Hendon outbreak " of scarlet fever, which affected North London 

 districts and Hendon. After inquiry, it was believed that the scarlet 

 fever in these districts followed the consumption of milk from a 

 particular farm at Hendon. Further, in these four districts wherein 

 scarlatina had shown an extravagant incidence upon the milkman's 

 customers, the disease had begun its peculiar incidence about the end 

 of November or beginning of December. In one of those districts 

 (South Marylebone), scarlatina continued day by day, and with 

 increasing force up to the date of the inquiry, to attack the customers 

 of the retail business. In two other districts (Hampstead and St 

 Pancras), after attacking in some numbers, for a few days at the end 

 of November and beginning of December, the customers of the busi- 

 ness, the disease showed no fresh attacks for about ten days (a short 

 but clearly defined intermission), and then about the middle of 



* Supplement to the Report of Local Government Board, 1882, p. 65. 



