1887.] on Etiology of Scarlet Fever. 151 



had for years past their attention fixed on these milk epidemics, and 

 in the Eeports of the Medical Officer many of these are described 

 with great detail ; amongst these Dr. Ballard's Report in 1870 on 

 Enteric Fever in Islington, Dr. Buchanan's on Scarlet Fever in South 

 Kensington in 1875, and Mr. Power's on Scarlet Fever in St. Giles's 

 and St. Pancras in 1882, are especially to be referred to. Mr. Ernest 

 Hart has tabulated all the outbreaks of milk epidemics which were 

 investigated before 1881 in vol. iv. of the Transactions of the Inter- 

 national Medical Congress for 1881. Now, analysing these out- 

 breaks as far as they refer to scarlet fever, there are several of them 

 where the assumption that the milk consumed acquired the jDower of 

 infection by contamination from a human source cannot be excluded. 

 This infection, if proven, would stand on the same footing as if due 

 to contagion from person to person ; for it is clear, whether the con- 

 tagium is conveyed from one person to another by air, food, drink, or 

 otherwise, it always remains contagion from person to person. Now, in 

 many of the cases of epidemics tabulated by Mr. Hart, and recorded by 

 subsequent observers — i. e. after 1881 — this mode of milk contamina- 

 tion cannot be excluded, as I said before ; but, comparing the dates 

 when the milk was supposed to have become so contaminated with 

 the dates when the milk has actually produced infection, it will be 

 found that a certain discrepancy exists, and, as will be shown later, 

 another mode of infection — viz. from a person affected with scarlatina 

 to the cow and through the cow to the milk and then to human beings 

 — cannot be excluded either. There are other epidemics recorded in 

 these tables in which the mode of infection of the milk is not ascer- 

 tained, and in a third set the milk acquired infective power in some 

 way or another, but certainly not from a human source. 



As an illustration of the first group of epidemics — i. e. probable 

 contamination from a human source — I will refer to a case recorded 

 by Dr. Eobertson, of Keswick, in which a dairy closely adjoined a 

 house where scarlet fever had existed for several weeks. The cows 

 were milked, every night and morning, into an open tin can, which was 

 carried across an open yard, past the affected house. The children 

 who first caught scarlet fever in the locality played about the yard 

 while in a state of desquamation. On one particular day a general 

 epidemic of scarlet fever broke out in the town, between thirty and 

 forty families being invaded. All those suffering from the disease 

 received their milk supply from this particular dairy-farm. Some 

 member of every family supplied had either a scarlatinal sore throat 

 or scarlet fever on this day. Other families suj^plied from a different 

 source escaped the disease. A lodger had the milk raw for supper 

 and was attacked. His landlady boiled her milk the same night and 

 escaped. We must here observe that a large number of fresh cases 

 of scarlatina occurred on the same day, and the inference from this 

 fact is that on some other day, shortly before, when the children who 

 were peeling from recent scarlet fever were playing in the yard, they 

 conveyed infection to the milk which was in their neighbourhood. 



