420 Calf Diphtheria. 



Cultivation. The bacillus develops only at body temperature, and 

 only auaerobieally. Artificial cultivation succeeds on blood serum, agar 

 containing blood serum, bouillon, and in milk. On serum agar, colonies 

 2 to 3 mm. in diameter develop with striped surface and consisting of 

 felt-like braided threads. At the same time indol and gas are produced, 

 which have an unpleasant cheesy odor (Jensen, Ernst). Bouillon is 

 uniformly clouded in a few days, liciuid blood serum is coagulated. No 

 growth results on potatoes. 



Pathogenicity. Inoculation of pus containing bacilli or of 

 a pure culture into or under the skin of a rabbit causes pro- 

 gressive necrosis of the skin (see p. 102). Inoculation into 

 mice produces also skin necrosis, while guinea pigs, dogs, cats 

 and chickens are not susceptible to the infection. A sub- 

 cutaneous injection in cattle, hogs and pigeons causes only 

 local necrosis of the skin, in horses cold abscesses. (According 

 to L. Roux the experimental necrosis develops especially after 

 adding other bacteria to the pure culture, whereas alone it 

 frequently causes only cold abscess.) The introduction of 

 pseudo-membranes of affected calves into the nose and into 

 the mouth of lambs only several days old, produces a diph- 

 theritic stomatitis, while if sewed in under the eyelids a severe 

 conjunctivitis with keratitis results. Feeding experiments al- 

 ways give negative results. 



The, bacillus necrophorus, as has been proven by Bang and later by 

 Jensen, plays an important part in various diseases of animals, in which, 

 during their course necrotic and gangrenous processes develop as com- 

 plications. Thus the necrotic and croupous diphtheritic processes of 

 the mucous membranes in general, especially however of the mucous 

 membranes of the pharynx and the intestines (among others in hog 

 cholera), in sheep, on the lips and on the borders of the nostrils, or 

 on the external genital organs (see Vol. II), further in gangrene of 

 the hoofs and the teats, in necrotic dermatitis, etc., are freciuently pro- 

 duced by this bacillus. In addition to these the occasional necrotic areas 

 in the liver, kidneys, lungs, etc., may be attributed to this cause. 



In the great majority of cases the bacillus necrophorus attacks 

 only tissue that is already affected. Successful infection experiments, as 

 well as metastatic necrotic areas, proved however that under specially 

 favorable conditions it may attack even healthy tissues. Its character- 

 istic location at the border of the necrotic and the living tissue, proves 

 that it exerts its pathogenic action, the necrosis of the tissue elements, 

 by the elimination of toxic products. 



The bacillus necrophorus is described in literature under various names and 

 is identical with the: Bacillus necrophorus, Fliigge; Bacillus diphtheriae vitulorum, 

 Loeffler; Bacillus necroseos, Salomonsen; Bacillus filiformis, Schlitz; Bazillus des 

 Kalbernoma, Eitter ; Streptothrix cuniculi, Schmorl ; Actinomyces cuniculi, Gasperini ; 

 Actinomyces necrophorus, Neukirch, and Streptothrix necrophora, Ernst (L. Eoux). 



Natural infection may probably be explained by stating that 

 the bacillus necrophorus, which is very extensively distributed 

 in nature, is among others frequently contained in the feces 

 of herbivorous animals, and owing to its anaerobic character 



