Bacilli Resembling the Diphtheria Bacillus 445 



amined in New York ; they seem to have no relationship to 

 diphtheria, and are never virulent. 



Dr. Alice Hamilton* carefully studied 29 organisms, of 

 which 26 corresponded fully with the pseudo-diphtheria 

 bacilli. They were divisible into three groups: I, Those 

 non-pathogenic for guinea-pigs; II, those that produce 

 general bacteremia in guinea-pigs, and are neutralized by 

 treatment with the serum of a rabbit immunized against a 

 member of the group; III, organisms which form gas in 

 glucose media, produce bacteremia in guinea-pigs, and are 

 neutralized neither by diphtheria antitoxin, nor by pseudo- 

 diphtheria. Some of the organisms of the second group are 

 also pathogenic for man. Instead of regarding the pseudo- 

 diphtheria bacillus as a harmless saprophyte, Dr. Hamilton 

 believes it an important organism explaining some of the 

 paradoxes that we find at hand. Thus, cases of supposed 

 diphtheria irremediable by or deleteriou sly affected by anti- 

 toxic serum may depend upon one of these organisms. It 

 is also probably one of them that Councilman found in his 

 case of ''general infection by B. diphtherias," and that 

 Howard encountered in his case of acute ulcerative endo- 

 carditis without diphtheria, from the valves of whose heart 

 cultures of a diphtheria-like organism not pathogenic for 

 guinea-pigs were isolated. 



The observation of Martini, | that the diphtheria bacillus 

 will not grow in fluid antitoxic serum in which the pseudo- 

 diphtheria bacillus thrives, I have not been able to confirm. 



Having practically the same cultural and staining reac- 

 tions as the diphtheria bacillus, the question presents itself, 

 Is the pseudo-diphtheria bacillus the diphtheria bacillus in 

 an attenuated condition? This question we are, as yet, 

 unable to answer. Every attempt to bring back virulence 

 to the pseudo-bacilli has failed, and we know it only as a 

 saprophyte. 



*"Jour. Infectious Diseases," 1904, i, p. 690. 



t "Centralbl. f. Bakt. u. Parasitenk.," Jan. 30, 1897, Bd. xxi, No. 3. 



