432 MILK 



for the whole group of 2 per cent, of the deaths may be attributed 

 to infected milk." 



High infant mortality has been commonly ascribed to con- 

 taminated milk, although no specific germ so far has been identi- 

 fied as the cause of cholera infantum. The importance of milk 

 in relation to this disease has also been exaggerated, and Schere- 

 schewsky goes so far as to state that "the hypothesis that the 

 ordinary saprophytic germs of milk produce disease and death in 

 infants is singularly lacking in experimental confirmation." 



Admitting that the culpability of milk as a carrier of infection 

 has been exaggerated, the fact that the virus of diseases is dis- 

 seminated through its means cannot be denied, and any study 

 that leads to the decrease of milk-borne morbidity or death should 

 be encouraged. 



Milk-borne epidemics have characteristics which usually dis- 

 tinguish them clearly from epidemics due to other causes. The 

 explosive outbreak of a milk-borne epidemic is similar to that of 

 a water-borne epidemic, but differs inasmuch as it is usually con- 

 fined to patrons of a particular dealer. It is true that not all those 

 who consume milk from the same supply are taken ill. As a mat- 

 ter of fact, among the users of the same supply the number of 

 those taken ill may vary from a small percentage to 80 or 90 

 per cent. This, of course, is due to certain factors that have to 

 be taken into account, the most important of which are: 



1. The quantity of milk consumed: It is obvious that the larger 

 the quantity of milk consumed, the greater is the intoxication, 

 and since it is a well-known fact that while a moderate number 

 of bacteria may not cause disease, a large number is more liable 

 to do so. This is the reason why milk-borne epidemics are more 

 frequent among the well-to-do class than among poorer people, 

 since the latter purchase their supply in moderate quantity for 

 immediate consumption, while the former use milk more liberally. 

 The following figures taken from Swithinbank and Newman's 

 Bacteriology of Milk clearly illustrate the relation of the amount 

 of milk consumed to the number of cases of disease occurring: 



RELATION OF AMOUNT OF PARTICULAR MILK CONSUMED TO INCIDENCE OF EPIDEMIC 

 (Wimbleton and Morton 1886-87) 



Invaded Invaded 



Amount of particular milk Total No. per cent. Total No. per cent, 



consumed daily per household. houses. invaded, of total, persons, invaded, of total 



Less than 1 pint 81 39 48.1 315 68 21.6 



1 to 1.5 pints 102 62 61.7 472 162 34.5 



2 to 2. 5 pints 43 32 76.7 207 87 42.0 



3 or more pints 48 39 81.2 362 169 46.6 



The fact that women and children are larger consumers of 

 milk than men explains the greater liability of women and chil- 

 dren to milk-borne infections. 



