CHAPTEE XVI. 



DIPHTHERIA. 



There is no better example of the valuable contributions of 

 bacteriology to scientific medicine than that afforded in the case 

 of diphtheria. Not only has research supplied a means of distin- 

 guishing true diphtheria from conditions which resemble it, but 

 the study of the toxins of the bacillus has explained the manner 

 by which the pathological changes and characteristic symptoms 

 of the disease are brought about, and has led to the discovery 

 of the most efficient means of treatment, namely, the anti-diph- 

 theritic serum. 



Historical. — The first account of the bacillus now known to he the 

 cause of diphtheria was given by Klebs in 1883, who described its 

 characters in the false membrane, but made no cultivations. It was 

 first cultivated by Loffler from a number of cases of diphtheria, his 

 .observations being published in 1884, and to him we owe the first 

 account of its characters in cultures and some of its pathogenic effects 

 on animals. The organism is for these reasons known as the Klebs- 

 Lbffler bacillus, or simply as Lbffler's bacillus. By experimental in- 

 oculation with the cultures obtained, Loffler was able to produce false 

 membrane on damaged mucous surfaces, but he hesitated to conclude 

 definitely that this organism was the cause of the disease, for he did 

 not find it in all the cases of diphtheria examined, he was not able to 

 produce paralytic phenomena in animals by its injection, and, further, 

 he obtained the same organism from the throat of a healthy child. This 

 organism became the subject of much inquiry, but its relationship to 

 the disease may be said to have been definitely established by the 

 brilliant researches of Eoux and Yersin, which showed that the most 

 important features of the disease could be produced by means of the 

 separated toxins of the organism. Their experiments were published in 

 1888-90. 



General Facts. — Without giving a description of the patho- 

 logical changes in diphtheria, it will be well to mention the out- 

 standing features which ought to be considered in connection 

 with its bacteriology. In addition to the formation of false 

 membrane, which may prove fatal by mechanical effects, the 

 chief clinical phenomena are the symptoms of general poisoning 



