BREATHING 24I 



carriers. While the diphtheria germs do not remain in the 

 patient's mouth for any such length of time as those of 

 typhoid fever linger in the body, they do remain there from 

 three to six weeks, and sometimes for some months. As 

 long as they are present the person is a source of danger to 

 his associates. A person may become a carrier of diphtheria 

 germs who has not himself had the disease. It frequently 

 happens in a school that after one or two cases of diphtheria 

 have appeared, quite a number of the children will be found 

 to have diphtheria germs in their throats, having obtained 

 them, doubtless, from associating with the patients. To 

 these carriers the bacilli may not be doing injury, since some 

 children are immune ; but as long as the germs are present in 

 their mouths the carriers are a source of danger to others who 

 may not be immune. The most efficient method of prevent- 

 ing the distribution of this disease through a school, or any 

 institution, is to examine the throats of all children who are 

 associated with cases of true diphtheria, and then temporarily 

 to isolate those whom a microscopic examination shows are 

 carriers. By such means it is practically always possible to 

 check the spread of diphtheria and to prevent epidemics in 

 schools, and the method is more effective than that of closing 

 the schools. 



