Pathogenesis. 267 



A similar view would probably also apply to the part of the 

 bacillus suisepticus. Ovoid bacteria which correspond in all 

 their characteristics to these organisms occur as saprophj'tes 

 in healthy hogs (see p. 129). Animals which have been injected 

 subcutaneously with filtered cholera blood frequently develop 

 acute, fibrinous, catarrhal or necrotic pneumonia, in which the 

 ovoid bacteria are present in great numbers. 



These findings can be explained satisfactorily only by con- 

 sidering that the bacillus suisepticus, like the bacillus suipes- 

 tifer, finds favorable conditions for its propagation in the body 

 affected by the cholera virus, and thereby exerts its pathogenic 

 action in the production of a multiple necrotic pneumonia. 

 From case to case one or the other of these bacilli, and fre- 

 quently both at the same time or following each other, may 

 become conspicuous in the pathological changes. 



Therefore in association with the primary cholera infection 

 there may be not only the characteristic anatomical changes of 

 hog cholera present, but also those of swine plague; thus not 

 only the anatomical hog cholera, but also the anatomical swine 

 plagiie as it occurs in outbreaks of cholera, either in association 

 with the former, or alone, is primarily brought on by the filtera- 

 ble cholera virus. In all of these cases only one disease comes 

 into consideration, and that is hog cholera, which however mani- 

 fests itself in various clinical and anatomical pictures, depending 

 on the secondary infection, namely either as a pure septicemia, 

 as hog cholera or as pure swine plague, or the changes may indi- 

 cate a mixed infection with the last two forms. Accordingly a 

 septicemic, a pectoral and a mixed form of hog cholera may be 

 distinguished. It should however be distinctly understood that 

 the intestinal and the pectoral changes in the organs are only 

 secondary complications, and that strictly they should not be 

 considered as belonging to the manifestations of hog cholera. 



Contrary to the ahove-aescri.jed views relative to the secondary 

 action of the bacillus suisepticus, Ostertag contends that pure swine 

 plague may occur as an independent acute disease even under favorable 

 hygienic conditions, infecting old, as well as young animals, and causing 

 losses amounting to TS*^ . He further claims that chronic swine plague 

 is directly connected with the acute, destructive, classical swine plague. 

 He bases this view mainly on the observation that the acute form 

 may pass into chronic, and as such may again introduce the acute 

 fatal form, and that with the material of both forms, either of the 

 forms may he alternately produced (see also p. 128). 



On the other hand Uhlenhuth and his co-workers perfectly agree 

 with the view of Hutyra. They found that pigs infected with filtrated 

 blood frequently develop a pleuro-pneumonia, and that the treatment 

 of pigs with immune serum protects them also against a secondary 

 pneumonia. They therefore emphasize the suggestion that changes 

 in the lungs belong to the accompanying hog cholera symptoms, and 

 therefore are to be considered as symptoms of the disease. Therefore 

 the so called pure cases of swine plague in outbreaks of cholera should 

 be considered as cholera infections, and the previously considered mixed 



