» DIPHTHERIA. 335 



bacillus when isolated is tested by inoculation the test may prove 

 to be entirely fallacious. 



Loffler and Von Hoffman both found bacilli in healthy throats, 

 and thus created doubt as to the importance of the Loffler bacillus. 

 Hoffman found this bacillus in the throats of twenty-six out of 

 forty-five individuals, some of them suffering from scarlet fever, 

 measles or some other non-diphtheritic affections, while the rest were 

 healthy. The bacilli from these sources showed slight differences 

 in morphological and cultural characteristics, and Hoffman was 

 unable to decide whether these bacilli were diphtheria bacilli, which 

 had become harmless, or whether they were accidental epiphytes, 

 belonging to a closely allied but different species. 



Roux and Yersin confirmed these observations. In a hospital 

 for ehildi-en in Paris without any question of the existence of 

 diphtheria they found the so-called pseudo-diphtheria bacilli in 

 fifteen cases out of forty-five. In a school, in a seaside place 

 entirely free from diphtheria, the same bacilli were found in 

 twenty-six out of fifty-nine children. They were also found in 

 children with simple sore throats, and in five out of seven cases 

 in measles. Roux and Yersin concluded that these bacilU were 

 not distinct from the Loffler bacillus. There were slight variations, 

 but there was no constant difference except in their pathogenic 

 properties. The appearance of the colonies, the growth in broth, 

 and the peculiar morphological elements showed chal'acters common 

 to both, and there was, in fact, less difference than there is 

 between attenuated anthrax and virulent anthrax in forn^ and in 

 cultures; but inoculations of the bacillus did not cauSe death, 

 though in some cases in guinea-pigs there was marked oedema at 

 the seat of inoculation. On the other hand, Lbffler's bacilli 

 possess different degrees of virulence, some cultures producing only 

 temporary oedema, while others cause death in twenty-four hours. 



Virulent diphtheria bacilli subjected to a current of air can 

 in two weeks be deprived of their virulence partially, and in four 

 weeks entirely. Weakened bacilli can be raised in virulence by the 

 simultaneous injection of the streptococcus of erysipelas, but bacilli 

 deprived of their virulence and bacilli originally non-virulent cannot 

 be made to assume virulent properties. Escherich maintained 

 that they could be distinguished by comparative cultures ; that the 

 pseudo-diphtheria bacilli made broth alkaline, so that in forty-eight 

 hours litmus was turned red by Lbffler's bacilli and blue by the 

 false bacilli. The bacilli themselves, according to Hoffman, are, as 

 a rule, shorter, wider and more uniform in size. 



