282 INFECTIVE DISEASES. 



farm suffered from latent scarlet fever does not appear to have 

 been ascertained. 



There is, it is true, no evidence to show that any one daily carried 

 infection to the milk, but the exact path of infection is not always 

 easy to trace ; and because it was not actually traced it was hardly 

 reasonable to assume that the possibility of contamination from a 

 human source could be altogether eliminated. 



In attempting to communicate scarlet fever to cows Professor 

 M'Fadyean confirmed the negative results which had been experi- 

 enced in some earlier experiments by Klein. In 1882 Klein 

 inoculated and fed cows and yearling heifers with diseased products 

 from human patients, using desquamated cuticle and the discharges 

 from the throat ; but the experiments all failed. M'Fadyean's 

 failures were still more marked. Cows and calves were inoculated 

 with blood from scarlet fever patients, and they were made to drink 

 water thickened with desquamated cuticle, but all the experiments 

 proved unsuccessful. 



The avithor believes that the outbreak at Hendon was one 

 of cow-pox, which was prevalent in this country in 1886. The 

 outbreak in Wiltshire could not be distinguished bacteriologically 

 or clinically or in its micropathology, from the disease at Hendon, 

 and the Wiltshire outbreak proved on investigation to be true cow- 

 pox. This conclusion was questioned at the time, as cow-pox was 

 generally believed to be extinct in England ; but that view is 

 entirely fallacious, and the author's conclusions have since been fully 

 confirmed by independent observers, whose work will be referred to 

 in another chapter (p. 321). 



Stamping-out System. — The Notification Act of 1890 may be 

 voluntarily adopted in sanitary districts, but it would be a great 

 advantage if notification were carried out uniformly all over the 

 country. Prompt information may lead to detecting the origin of 

 cases of scarlet fever, and isolation and disinfection will assist in pre- 

 venting its spread. Epidemics have occurred on a large scale owing 

 to scarlet fever existing among those engaged in dairy work, and 

 the precaution not being taken of stopping the milk supplied to the 

 consumers. Scarlet fever cannot be so readily controlled as small- 

 pox, for it may be spread by mild cases before the nature of the 

 disease is suspected, and small-pox cannot be conveyed in milk. 



