368 PATHOGENIC BACTERIA IN MILK 



ance, " rainfall is more important than temperature in relation to 

 epidemic diarrhoea." Rain washes the air, if the expression may- 

 be allowed, and carries to the surface aerial dust. It, of course, 

 also washes the surface of the soil and removes surface pollution, 

 and with it micro-organisms capable of infecting infants, usually 

 by food. Thus the relationship between these meteorological con- 

 ditions and milk, though an open question, may be an essential 

 one to the origin of the disease. In any event, it seems clear 

 that milk is probably the common vehicle of infection (Ballard, 

 Del^pine, Newsholme), and this probability must now be referred to. 



The relationship of milk to epidemic diarrhoea.— Most of 

 our knowledge respecting the part played by milk in the production 

 of epidemic diarrhoea is derived from cases of the disease traceable 

 to milk infection. These cases have occurred in outbreaks or 

 sporadically. 



In 1892 Gafifky^ recorded an instance in which three men 

 connected with the Hygienic Institute at Giessen were suddenly 

 taken ill. They were the assistant, the chemist, and the janitor. 

 They had chills, fever, diarrhoea, and general symptoms. The 

 only article of diet of which they had all partaken was milk, 

 which was traced to a cow suffering from enteritis. The milk of 

 this cow as it left the udder contained no bacteria. But bacteria 

 gained access during the milking from the dried particles of faecal 

 matter on the posterior portion of the udder. In these particles 

 was found a bacillus which proved very pathogenic for mice and 

 guinea-pigs, and which corresponded to an organism isolated from 

 the stools of the patients. 



In 1894 an outbreak occurred at Manchester,^ characterised 

 by diarrhoea, sickness, and abdominal pains. The cases numbered 

 160 in 47 houses, or just 50 per cent, of the houses served by 

 one and the same milk seller. Raw-milk drinkers were the 

 chief sufferers, and those not drinking the implicated milk did not 

 suffer. Dr Niven visited the farm whence the milk came, and 

 found that it was the milk from the farm itself, and not the added 

 milk from a more distant farm which supplemented the farmer's 

 stock, that had caused the epidemic, the home farm milk only being 

 sent into the affected district. Near the farm were 40,000 tons of 

 privy-midden refuse. Two streams ran near the farm, meeting 

 below, one fouled by the drainage of the " tip," and the other being 



^ Deut. Med. IVoc/i., vol. xviii., p. 14. 



2 Annual Report of Medical Officer of Health of Manchester^ 1894 (Dr 

 Niven). 



li 



