372 BACTERIA IN DIPHTHERIA. 



obtained it in pure cultures, and by inoculations in pigeons, chickens, 

 rabbits, and guinea-pigs proved that it gave rise to a diphtheritic 

 inflammation when inoculated into the mucous membrane of the 

 trachea, conjunctiva, pharynx, or vagina. In a second communica- 

 tion Loffler reported his success in finding the same bacillus in ten 

 additional cases, and also that he had isolated from the same source 

 a non-pathogenic bacillus which resembled it very closely. This 

 pseudo-diphtheria bacillus has since been found by other bacteri- 

 ologists (Von Hoffmann, Roux and Yersin), and it is uncertain 

 whether it is to be considered a distinct species, or a non-pathogenic 

 variety of the diphtheria bacillus as maintained by Roux and Yersin. 

 But its occasional presence does not invalidate the very positive ex- 

 perimental evidence relating to the specific pathogenic power of the 

 true diphtheria bacillus. 



Loffler, in 1890, reviewed the evidence upon which this bacillus is 

 now generally conceded by bacteriologists to be the specific infectious 

 agent in true diphtheria. The following are the principal points in 

 the demonstration : 



FIRST. It is found in all undoubted cases of diphtheria. In 

 support of this we have the results of researches made by Loffler, 

 Wyssokowitsch, D'Espine, Yon Hoffmann, Ortmann, Roux and 

 Yersin, Kolisko and Paltauf, Zarinko and Sorensen, who in nearly 

 every case have demonstrated without difficulty the presence of this 

 bacillus. On the other hand, Prudden failed to find it in a series of 

 twenty-four cases studied by him ; but his own account of these 

 cases indicates that they were not cases of true diphtheria. He says 

 in a subsequent communication : 



" In view of the doubt existing among practitioners as to whether all 

 forms of pseudo-membranous inflammation should be called diphtheria or 

 not, and with the purpose of making a wholly objective study, the writer 

 distinctly stated at the outset of that paper that all the fatal cases of exten- 

 sive pseudo-membranous laryngitis, as well as pharyngitis, should in his 

 study be considered as cases of diphtheria. This left the question as to the 

 propriety of establishing separate groups of pseudo-membranous inflamma- 

 tion open and free from bias. It was distinctly stated, however, that six- 

 teen out of the twenty-four cases occurred in a large asylum, in which 

 measles and scarlet fever were prevalent during the period in which these 

 studies were under way. Five other cases in another asylum were ex- 

 posed to similar conditions." 



In a subsequent series of "twelve cases of fatal pseudo-mem- 

 branous inflammation occurring in two children's asylums, in which 

 t T many months there had been no scarlatina and no measles, and 

 in which there was no complicating suppurative inflammation and 

 ii" < i \ -sipelas," Prudden (1890) obtained Loffler's bacillus in cultures 

 t i"in Cloven, and he says : 



" We are now, it would seem, justified, as it did not appear to the writer 



