PATHOGENICITY FOR MAN 235 



flora of a carrier of Type IV, once in an individual free from other 

 pathogenic bacteria, and once during an attack of mild bronchitis 

 subsequent to a cold. The other pneumococci encountered belonged 

 to the heterogeneous group. 



Another recent report is that of Brown and Anderson, 152 who 

 found no strains of the first three types, but only those of the re- 

 maining types — all of low virulence for mice — from a small series 

 of normal subjects. Christie (1932), 232 in making cultures from 

 the throats of nurses in a Glasgow hospital, isolated pneumococci 

 from eleven of twelve nurses in the pneumonia ward but none from 

 nurses in the control wards. Of the organisms found in the nurses 

 exposed to pneumonia, Christie demonstrated Type I pneumococci 

 four times and Type II seven times. Whether the organisms found 

 corresponded to the types prevalent among the pneumonia pa- 

 tients was not stated in the communication. 



The classification of carriers of Pneumococcus based on re- 

 peated bacteriological examinations extending over a year or more 

 as drawn up by Webster and Hughes was slightly modified by 

 Bliss, McClaskey, and Long (1934). 131 After a year's study of 

 young adults, the authors divided the subjects into non-carriers 

 and chronic carriers, the latter group including those persons who 

 intermittently exhibited pneumococci in the throat. While the so- 

 called intermittent carriers might or might not yield positive cul- 

 tures on repeated examination, the cultures when positive were 

 consistently of the same type of Pneumococcus in any given case, 

 indicating to the authors a chronic condition with constant bac- 

 teriological findings only as to type. Furthermore, the authors 

 considered that their demonstration added evidence in favor of the 

 stability of pneumococcal types in the human body. From the 

 foregoing discussion it would seem to be more logical to designate 

 healthy individuals who harbor pneumococci in the nose and throat 

 for short periods of time as temporary carriers and those in whom 

 the organisms persist for longer periods as chronic carriers. A 

 subdivision of the latter into continuous and intermittent carriers 



