26 
and other physicians who so kindly responded to the circular letter 
sent out by the Surgeon-General requesting reports of milk epi- 
demics.) The 90 epidemics compiled by Car0e have not been in- 
cluded because of lack of time and space. No attempt has been made 
to note every outbreak reported as spread by milk ; many cases where 
the evidence did not seem entirely convincing have been omitted. 
Necessarily much of the evidence upon which it is determined 
whether or not an epidemic is conveyed by milk is circumstantial; 
the same may be said of water-borne disease, and indeed of many of 
the things in daily life which we firmly believe. In an explosive 
outbreak of an infectious disease, to find that all persons attacked 
had used one milk supply, that they had apparently nothing else in 
common, that no cases occurred except among users of this milk, and 
then to isolate from the milk the specific organism of the disease in a 
virulent state, is believed to be good evidence in the absence of other 
explanation. It is not to be inferred that this has been taken as an 
absolute standard up to which all epidemics must come before being 
considered as spread by milk, for to do this the outbreak would have 
to occur in a locality previously entirely free from the disease and 
the development of secondary-contact cases, which is necessarily a 
common occurrence, would wrongly exclude such epidemics. Then, 
too, the difficulty of isolating the Eberth bacillus when in small 
amount and accompanied by large numbers of other organisms and 
our lack of absolute knowledge as to its specificity, and the fact that 
no organism has as yet been isolated which is commonly accepted as 
the causal agent of scarlet fever, would lead to erroneous conclusions 
if the isolation of a specific organism were insisted upon. 
TYPHOID FEVER. 
Schiider® in 1901 collected from the literature 650 typhoid epi- 
demics the supposed cause of which had been reported. Four hun- 
dred and sixty-two were reported as spread by water, 110 by milk, 
and 78 by all other means. This places milk second only to water as 
a carrier of typhoid infection. But the ratio of 462 to 110 probably 
by no means shows the true relation of water and milk as producers 
of such outbreaks. Schiider’s epidemics were collected mainly from 
continental Europe, where milk epidemics are apparently not as com- 
mon as in England and America, due possibly to the more or less cus- 
tomary practice in Europe of using pasteurized or cooked milk. The 
result of such a compilation as the above may also have been affected 
by the fact that until comparatively recently water has received 
much more attention in typhoid epidemiological work than has milk. 
® Schiider, Zeitschrift f. Hyg. und Infectionskrankheiten, 1901, XXXVIII, 
p. 343. 
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