212 BACTERIA PRODUCING DIPHTHERITIC INFLAMMATIONS 



keeping it in the incubator for eighteen hours and then pouring plates 

 with glycerin agar. In the cultivation of larger masses of the bacilli 

 for the production of the toxin, bouillon is generally employed. Some 

 strains of bacilli grow readily and abundantly on it, others only feebly. 

 The bouillon should be slightly alkaline to litmus. Frequently the 

 growing and multiplying bacilli, after twenty-four to forty-eight 

 hours, produce a diffuse cloudiness in the bouillon and form a film 

 or pellicle on its surface. 



Toxin Formation. The diphtheria bacillus forms a soluble, very 

 poisonous toxin, which when inoculated into a susceptible animal, 

 produces all the general symptoms of the disease. 



Diphtheria Antitoxin. This is prepared by the systematic injection 

 of diphtheria toxin and subsequently cultures of diphtheria bacilli 

 into a perfectly healthy horse. The technique and details are almost 

 identical with those employed in the preparation of tetanus antitoxin, 

 and are fully described in the chapter on the Bacillus tetani. 



Animals Susceptible. Young cats in houses where diphtheria occurs 

 among children, frequently contract the disease. Guinea-pigs, young 

 cats, young rabbits, and other animals can easily be infected experi- 

 mentally. Many animals are susceptible to experimental intraperi- 

 toneal injection with diphtheria toxin. 



In making a diagnosis of diphtheria the possibility of the presence 

 of the pseudodiphtheria bacillus must always be considered. As the 

 latter cannot always be distinguished morphologically from the true 

 Bacillus diphtherise, animal experiments are sometimes necessary to 

 decide the question. 



BACILLUS NECROPHORUS. 



The Bacillus necrophorus was first found by Loeffler in diphtheria 

 of calves and called by him Bacillus diphtherise vitulorum (Latin, 

 vitulus, a calf). It is also known as Streptothrix necrophora, Bacillus 

 necroseus, Streptothrix cuniculi (Latin, cuniculus, a rabbit). 



Occurrence and Pathogenesis. It is a very common cause of diph- 

 theritic, necrotic inflammations among domestic animals. Ostertag, 

 quoting Bang, enumerates the following pathologic conditions in 

 which it has been found: 



Diphtheria of calves. 



Furunculosis of cattle. 



Dry gangrene of the udder of cows. 



Multiple necrotic foci in the liver of cattle. 



Multiple abscess in the liver of cattle. 



Diphtheritis of the uterus and vagina of cows. 



Diphtheritic necrosis of the small intestines of calves. 



Embolic pulmonary necrosis in cattle. 



Embolic myocardial necrosis in cattle. 



