654 BACTERIA OF THE RESPIRATORY TRACT 



yielded 43 per cent positives. Crypt cultures, however, from these same tonsils yield- 

 ed 97 per cent positives, and in almost all the hemolytic variety was greatly predom- 

 inant. Furthermore in another series of cultures from the throat and pharynx 58 per 

 cent yielded hemolytic streptococci; and in persons without tonsils cultures similarly 

 made yielded them in 15 per cent, and in these persons were found either bad teeth 

 or tonsil remnants. 



It appears that the crypts are an almost constant source of hemolytic streptococci, 

 and this location may be considered in a sense their normal habitat. We have not 

 been able to find any other part of the body that so constantly harbors them. The 

 throat, as we have known for a long time, is their chief source and habitat in the body, 

 and from the throat they may be distributed to various parts of the body by contact 

 and otherwise. Or they may be transferred to other persons through the usual channels 

 of transmission of respiratory diseases. This point deserves emphasis. Nearly every- 

 one is harboring in the tonsils or throat hemolytic streptococci which have not been 

 differentiated from strains that cause serious infections. Some of these strains are less 

 virulent, but not all. Presumably such bacteria may at times cause arthritis, iritis, 

 and other focal infections, but finding them in the tonsil may mean nothing in rela- 

 tion to a possible systemic disease. 



The incidence of hemolytic streptococci in the normal throat has been studied by 

 many workers, and the percentages as found range from 10 to 60 per cent or higher. 

 From the mass of literature on this point the impression may be gained, indeed the 

 conclusion has been drawn by some, that this organism does not occur in the throats 

 of some persons. Others believe that certain persons are definite carriers in that they 

 constantly harbor large numbers of the organisms in the throat. To test this point, I 

 made throat cultures from a large group of adult persons, three or more times, with 

 the following results: All at some time during an interval of about one month showed 

 the presence of hemolytic streptococci in the throat. Probably they might all have 

 been positive in a shorter time had more cultures been taken at shorter intervals. The 

 percentages positive of the different groups varied from 33 to 66. 



On the whole, throat cultures from tonsillectomized persons contain fewer hemo- 

 lytic streptococci than those made from persons with tonsils.' It has been shown, too, 

 that in the naso-pharynx the incidence and numbers of these and other bacteria 

 (pneumococci, hemophilic bacilli) are decidedly less in children whose adenoids and 

 tonsils have been removed. 



The incidence of hemolytic streptococci in the adenoids has been studied by 

 Pilot and Pearlman^ who found them common in the naso-pharynx and its vegeta- 

 tions. From naso-pharyngeal swabs and the surface of the adenoids they were found 

 in 55 per cent; from the depths between the folds of the cryptlike depressions of the 

 adenoids of the same persons in 61 per cent in larger numbers. The excised tonsils 

 of the same patients revealed them in still larger numbers in 95 per cent. These strep- 

 tococci agree in their morphology, cultural characteristics, fermentation reactions, 

 and pathogenicity, and are practically identical with hemolytic streptococci from 

 various human sources. The adenoids, therefore, like the pharyngeal tonsils must be 

 considered as common foci harboring hemolytic streptococci. 



' Pilot, T.: ibid. ' Pilot, I., and Pearlman, S. J.: ibid., 29, 47. 1921. 



