400 THE DIPHTHERIA BACILLUS GROUP 



Pathogenesis. Experimental Evidence of Pathogenesis. Loffler 1 ap- 

 pears to have been the first to attempt to establish the etiological 

 relationship of the diphtheria bacillus to the disease. He succeeded 

 in producing diphtheritic membranes on the mucous surfaces of 

 animals by rubbing cultures on the previously injured surface. Num- 

 erous laboratory accidents, where the organisms have been inadver- 

 tently swallowed with the subsequent development of typical clinical 

 diphtheria, complete the proof of the* etiological relationship of the 

 organism to the disease. 



Animal Pathogenesis. Laboratory animals, excepting mice and 

 rats, are very susceptible to the diphtheria toxin. Guinea-pigs are 

 particularly susceptible, and the subcutaneous injection of fatal or 

 nearly fatal doses of broth cultures is followed after one to three days 

 by the appearance at the site of inoculation of a membrane, edema, 

 and a serosanguineous exudate. A pleuritic' and frequently a peri- 

 cardial exudate are found as well. There is hyperemia of the abdom- 

 inal organs and a very characteristic swelling and hyperemia of the 

 adrenals. The kidneys are also usually hyperemic. Often there are 

 ecchymoses and even ulcers in the gastric mucosa. No bacilli are 

 found in the internal organs. Intraperitoneal injections are less severe 

 as a rule than subcutaneous inoculations of the same dose. There 

 is usually some peritoneal effusion which frequently contains diph- 

 theria bacilli. Intratracheal inoculation after mechanical injury is 

 commonly followed by the appearance of a false membrane and the 

 animal dies of toxemia; 2 intravaginal injection after injury of the 

 mucosa frequently leads to a necrotic inflammation with membrane 

 formation. 3 Repeated applications of diphtheria toxin to the con- 

 junctiva of rabbits cause a marked conjunctivitis with membrane 

 formation. 4 



Human. In man diphtheria bacilli are usually localized in the 

 false membranes, chiefly on the tonsils or pharynx, and these mem- 

 branes may extend to the nose, larynx, and mouth. The organisms 

 occasionally invade the blood stream. They may even extend into 

 the lungs causing a true bronchial pneumonia. Occasionally diph- 

 theria bacilli may cause rhinitis fibrinosa or simple rhinitis. 5 They 

 also are found in occasional cases of vulvitis gangrenosa and noma 



1 Loc. cit. 



2 Fraenkel, Deutsch. med. Wchnschr., 1895, 176. 



3 Roux and Martin, Ann. Inst. Past., 1894, p. 625. 

 4 Morax and Elmassian, Ann. Inst. Past., 1898, p. 219. 

 5 Neumann, Centralbl. f. Bakt., 1902, xxxi, 33. 



