SCARLET FEVER 253 



in life they are far less likely to be attacked, and the case- 

 mortality is very much less.^ The disease requires very 

 strict sanitary control, on account of the long period of 

 infectiveness, and the readiness with which the infective 

 material (desquamating epidermis) may adhere to clothing, 

 etc. 



No definite relation has yet been traced between the 

 prevalence of the disease and the rise and fall of the 

 ground-water, or any other meteorological condition. 



The disease is probably conveyed chiefly by fomites, and 

 the breath, sputa, and excreta of patients should be con- 

 sidered as infective. No doubt the chief danger lies in the 

 dissemination of the disease by the desquamating particles 

 of skin. Milk is a frequent source of the conveyance of 

 the disease. An epidemic due to the milk-supply will 

 exhibit some or all of the following features : (1) The out- 

 break is sudden, and many of the attacks are simultaneous, 

 (2) A large proportion of the households attacked have a 

 common milk-supply. (3) The incidence of the disease 

 will be greatest on the principal consumers. Thirty-two 

 epidemics of scarlet fever have been recorded as directly 

 due to contaminated milk-supplies by Dr. B. Hart in the 

 pages of the British Medical Journal since 1881. See the 

 reprinted ' Eeport on the Influence of Milk in spreading 

 Zymotic Diseases ' for the detailed reports of the outbreaks. 

 There is no evidence of the disease having been at any 

 time water-borne, nor is it air-borne to any considerable 

 extent, so that hospitals need not be considered as a source 

 of danger to the surrounding neighbourhood. 



Pathogenesis. — The incubation period is from about two 

 to seven days, and a rash is not always found. Epidemics 

 are frequently ushered in by the occurrence of numerous 

 cases of ' sore throat,' and, as frequently happens in most 

 epidemics, the cases are less severe at the end of the 



