DIPHTHERIA 163 



paper to the possibility of error owing to the swab having 

 been rubbed on a small area of the throat, also to the 

 ' crowding out ' of the bacilli, which may occur owing to 

 the presence of common saprophytes, or, again, to the 

 destruction of the bacilli by the use of antiseptics. 



Distribution and Occurrence. — Diphtheria seems to be dis- 

 tributed more or less widely all over the globe, but is far 

 more prevalent in cold and temperate climates than in the 

 tropics. It is one of those few diseases in which a distinct 

 increase (which cannot be attributed entirely to improved 

 diagnosis) has taken place in the past few years. Some 

 twenty-five years ago the disease was far more prevalent 

 in rural districts than in towns, but during the past few 

 years, while it has decreased in rural, it has increased in 

 urban districts. Its tendency to reappear at intervals in 

 particular districts would point to the specific organism 

 having either a saprophytic tendency, or to its retaining 

 its vitality in dust, and thus rendering the site of previous 

 cases more or less permanently infective. 



Its distribution does not appear to be affected by other 

 diseases ; its mortality is highest during the last quarter, 

 and lowest in the summer months. There is no evidence 

 of any influence being exercised by race or sex, but the 

 mortality is highest at ages below five, and rapidly 

 diminishes after ten years of age. 



Transmission of the disease may take place by direct 

 infection, as in kissing, by the use of infected spoons, cups, 

 etc., or by inhaling the breath of a patient, or sputum or 

 discharges which have been permitted to dry without having 

 been disinfected. It would also be safest to treat the bowel 

 discharges as infective. The organism, if it finds its way 

 into milk, either from infection from an employe or through 

 the disease of cows themselves, multiplies with great 

 rapidity, and epidemics may thereby be occasioned. 



