DIPHTHERIA. 305 



cations of the disease are numerous, and that it undoubtedly 

 occurs as a complication in other diseases. But when all this 

 is taken into consideration the fact must still be accepted 

 that careful clinical observation and experimental investi- 

 gation have been made by many thorough workers, and that 

 these workers have assigned to a special bacillus the power 

 of giving rise to at least one form of diphtheria. It is 

 possible that the streptococcus may play an important part 

 in certain cases of diphtheria, but this has not yet been 

 actually proved ; whilst the evidence in favour of the specific 

 infective Klebs-Loffler bacillus is now almost overwhelming. 



As regards the streptococci that are found in this disease, it appears that 

 these organisms so fully described by Klebs, Formad, and Prudden and 

 Northrup, and later by Loftier and Babes, when inoculated give rise to 

 local inflammation, and even to inflammation of joints, &c. ; in no case, 

 however, do they appear to give rise to the formation of a false or a fibrinous 

 membrane. No doubt they play a part in the preparation of the tissues 

 for the diphtheria by weakening them so as to enable them to offer less 

 resistance to the action of the specific organism. These streptococci 

 may actually make their way into distant organs of the body, and it 

 has been found possible to make pure cultivations of them from such 

 organs. These, then, differ very markedly, as regards their distribution in 

 the body, from the diphtheria bacillus, which grows only at the point of 

 inoculation, manufactures all the poison in that position, the poison only 

 being carried into the body ; the bacilli remaining in situ, multiply 

 during the advance of the disease, and degenerate as soon as the tissues 

 begin to obtain the upper hand, which they do in all cases where recovery 

 occurs, and even in some cases where the patients afterwards die from the 

 effects of the absorption of the specific poison. 



The diphtheria bacillus, having been obtained pure, was 

 naturally seized upon by Loffler, then by Roux and Yersin, 

 and, lastly, by Brieger and Fraenkel for their experiments on 

 toxalbumens ; the way having been paved somewhat by 

 Hankin's discovery of albumoses in certain anthrax culti- 

 vations. 



The diphtheritic poison is always most active when alka- 

 line ; during the acid period already mentioned, the toxic 

 power is very considerably diminished. Moreover, if an 

 acid be added to a virulent alkaline filtered liquid, its 

 poisonous activity is immediately diminished ; but, curiously 

 enough, this property is immediately regained when the 

 fluid is again neutralized by the addition of a fixed alkali. 

 So virulent is the alkaline liquid that one-fifth of a cc. of 

 the filtered fluid, from a cultivation of the diphtheria bacillus 



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