Diphtheria Antitoxin 489 



From these data the writers conclude that it is not safe 

 to base an opinion regarding the maintenance of quarantine 

 upon the bacterioscopic findings independently of the clinical 

 history of the case. 



The occurrence of true diphtheria bacilli in the throats 

 of healthy persons has been a stumbling-block to many 

 practitioners uninformed upon bacteriologic subjects, who 

 fail to account for its presence and also fail to realize how 

 rare its appearance under such circumstances really is. 



Park * found virulent diphtheria bacilli in about i per 

 cent, of the healthy throats examined in New York city, 

 but diphtheria was prevalent in the city at the time, and 

 no doubt most of the persons in whose throats they existed 

 had been in contact with cases of diphtheria. He verv 

 properly concludes that the members of a household in 

 which a case of diphtheria exists, though they have not 

 the disease, should be regarded as possible sources of 

 danger, until cultures made from their throats show that 

 the bacilli have disappeared. 



In connection with the contagiousness of diphtheria the 

 recent experiments of Reyes are interesting. He has 

 demonstrated that in absolutely dry air diphtheria bacilli 

 die in a few hours. Under ordinary conditions their vitality, 

 when dried on paper, silk, etc., continues for but a few days, 

 though sometimes they can live for several weeks. In sand 

 exposed to a dry atmosphere the bacilli die in five days 

 in the light ; in sixteen to eighteen days in the dark. When 

 the sand is exposed to a moist atmosphere, the duration 

 of their vitality is doubled. In fine earth they remained 

 alive seventy-five to one hundred and five days in dry air, 

 and one hundred and twenty days in moist air. 



Diphtheria Antitoxin. Behring f discovered that the 

 blood of animals rendered immune against diphtheria by 

 inoculation, first with attenuated and then with virulent 

 organisms, contained a neutralizing substance (Anti-korper) 

 capable of annulling the effects of the bacilli or the toxin when 

 simultaneously or subsequently inoculated into susceptible 

 animals. This substance, held in solution in the blood- 

 serum of the immunized animals, is the diphtheria antitoxin. 



* "Report on Bacteriological Investigations and Diagnosis of Diph- 

 theria, from May 4, 1893, to May 4, 1894," "Scientific Bulletin No. i," 

 Health Department, city of New York. 



t " Deutsche med. Wochenschrift," 1890, Nos. 49 and 50; " Zeit- 

 schrift fur Hygiene," xn, i, 1892. 



