236 VETERINARY BACTERIOLOGY 



Immunity. The diphtheria bacillus, according to Ehrlich, 

 produces two types of poison, the true toxin and the toxone. The 

 first is responsible for the acute symptoms of poisoning, the latter 

 for the paralysis that frequently occurs during convalescence. 

 The haptophores of both toxin and toxone are believed to be 

 identical, and to be neutralized by the same antitoxin. A con- 

 sideration of the production of diphtheria antitoxin has been taken 

 up in the chapter on Toxins and Antitoxins, under the heading of 

 Immunity. Agglutinins may develop in the blood, but are not 

 constant, and are of no practical value in diagnosis. They may 

 be produced in experimental animals by the injection of killed 

 cultures of the diphtheria bacillus. Precipitins have likewise 

 been produced by artificial immunization, but usually cannot be 

 demonstrated in the blood of infected individuals. Bactericidal 

 sera may be prepared by repeated injections of killed, washed 

 cultures of diphtheria bacilli, and favorable results have been 

 reported in the use of such a serum in freeing the throat of con- 

 valescents from the bacteria. Its clinical value can scarcely be 

 said to be proved. Opsonins have not been demonstrated. 



The value of diphtheria antitoxin for prophylactic and curative 

 injections is well established. It has resulted in materially lessen- 

 ing mortality whenever it has been used. As much as 100,000 

 units have been injected in some cases, but the usual curative 

 dose is 8000 to 15,000 units. 



Bacteriologic Diagnosis. Sterile swabs are used to swab out the 

 throat and nose of the suspect, and are smeared over the surface 

 of blood-serum. Mounts made in five to eighteen hours thereafter, 

 stained with Lofner's methylene-blue, should show the character- 

 istic organism with its metachromatic granules. Diagnosis may 

 sometimes be made directly from smears taken from the throat. 



Transmission. The organism doubtless sometimes gains 

 entrance into the body by the inhalation of infective droplets, but 

 more commonly by the use of common drinking vessels and 

 through fomites. 



Bacillus pseudodiphthericus 



Synonyms. Bacterium pseudodiphthericum ; Mycobaderium 

 pseudodiphthericum; bacillus of Hoffman; Bacillus clavatus; 

 Corynebacterium pseudodiphthericum. 



