194 APPLIED BACTERIOLOGY 



The spread of the disease by the agency of milk is a 

 matter deserving special attention, particularly as the 

 establishment of creameries in so many parts of the 

 country may prove to be factors of great importance in 

 the dissemination of the disease. At these creameries 

 the milk of a very large number of cows is received twice 

 a day, and mixed in a large tank before passing through 

 the separator. Thus, if the milk from one cow or one 

 dairy contains the bacillus of diphtheria, it would be im- 

 possible to avoid the infection of the whole. The skim 

 milk so obtained is at some factories condensed in tins, 

 when the bacillus would probably be killed ; but at others 

 the milk is sold for human consumption, and as the 

 organism multiplies in milk at an enormous rate, it is 

 easy to understand how epidemics of great magnitude 

 might be caused. The only remedy for this would be to 

 insist on the sterilization of all milk leaving the dairy 

 factory, or the constant supervision and inspection of all 

 cows and employes. 



An epidemic of diphtheria due to the milk-supply will 

 exhibit features similar to those of a typhoid epidemic 

 produced in the same way. (1) The outbreak is sudden, 

 and many attacks occur together. (2) The greater pro- 

 portion of households attacked will have a common milk- 

 supply. (3) The incidence of the disease will fall chiefly 

 on the principal consumers. 



Fifteen epidemics of diphtheria have been recorded as 

 directly due to contaminated milk-supplies by Dr. E. Hart 

 in the pages of the British Medical Journal since 1881. 

 See reprinted ' Report on the Influence of Milk in spreading 

 Zymotic Diseases' for the detailed reports of the out- 

 breaks. 



Dust is undoubtedly a very important source of the con- 

 veyance of the disease, although it has been stated by 



