294 BACTERIA 



lus is pathogenic for the horse, ox, rabbit, guinea-pig, cat, 

 and some birds. Cases are on record of supposed infection 

 of children by cats suffering from the disease. The horse, 

 it will be remembered, yields the antitoxin which has saved 

 so many lives (Metropolitan Asylums Board Report, 1896). 



The influence of drainage, milk, and schools must not be 

 forgotten by sanitary authorities any more than the essen- 

 tial importance of adequate isolation hospital accommoda- 

 tion. Mr. Shattock's experiments on the effect of sewer air 

 upon attenuated Klebs-Loffler bacilli have been mentioned 

 (see p. 105). Nevertheless there can be no doubt that 

 emanations from defective drains have a materially predis- 

 posing effect, not, it is true, upon the bacilli, but upon the 

 tissues. Sore throats thus acquired are par excellence the 

 site for the development of diphtheria. 



The influence of school attendance has claimed the recent 

 attention of the Medical Officer of the London School Board 

 and the Medical Officer of the administrative County of 

 London. In London since 1881 there has been a marked 

 increase of diphtheria, which has occurred, though in a much 

 less degree, throughout England and Wales. 



The Registrar-General has only classified diphtheria as a 

 separate disease since 1855, when the death-rate per 1,000,. 

 ooo in England and Wales was stated as 20. The following 

 are the figures for four decades up to 1895 : 



AVERAGE DEATH-RATE PER MILLION OF THE POPULATION 

 FROM DIPHTHERIA IN ENGLAND AND WALES AND IN 

 LONDON (IN DECADES 1856-95) 



England and 



Wales. London. 



1856-65 246.9 225.4 



1865-75 124.8 123.5 



I 875~^5 129.0 176.7 



1885-95 210.6 421.4 



