DIPHTHERIA 193 



bacilli in their throats without manifesting any symp- 

 toms of the disease. Non-virulent varieties of the 

 diphtheria bacillus are not infrequently found in the 

 throats of healthy persons. Much attention has been 

 given by bacteriologists to the question as to how 

 long the bacillus may persist in the throats of con- 

 valescents from the disease. Drs. Park and Beebe, 



FIG. 7. Bacillus of diphtheria ; magnified 1000 diameters. 



of the New York Health Department, found in a 

 series of 605 cases that the bacilli disappeared in three 

 days in 304, in seven days in 176, in twelve days in 64, 

 in fifteen days in 36, in three weeks in 12, in four 

 weeks in 4, and in nine weeks in 2. This shows the 

 necessity for expert opinion before one who has re- 

 covered from the disease is allowed to associate with 

 susceptible children. 



