266 Hog Cholera. 



Against the idea that the bacillus suipestifer is the primary virus 

 of hog cholera are the experimental observations of Uhlenhuth and his 

 co-workers, who found that virus which was treated for one hour with 

 2.5% antiformin still proved virulent, while cultures of the bacillus 

 suipestifer lost their pathogenic action even for the very susceptible 

 rabbit, after being subjected to such a solution from 30 to 40 minutes, 

 the organism being readily dissolved by the antiformin. A similar 

 difference is also shown to exist by the fact that the hog cholera virus 

 is destroyed by shaking with a 10% uric acid only in four days 

 (Marxer), whereas the bacillus suipestifer is killed in 23 hours 

 (&tiHin^)-; the observation that the bacillus suipestifer agglutinates 

 the serum from hogs affected with acute cholera in dilutions of only 

 1:5-20 (Uhlenhuth), whereas in animals artificially infected with this 

 bacillus the agglutination takes place in higher dilutions (1 :1000 and 

 over) should also be noted. Moreover in virulent hog cholera serum 

 there are no opsonins or bacteriotropins, which have an influence on 

 the bacillus suipestifer (Broil). 



Eecently (1907) Lourens took a stand relative to the importance of the bacillus 

 suipestifer as the primary cause of hog cholera, when he proved that this bacillus 

 passes through the porcelain filter in a granular form, and that it may later 

 multiply in the filtrate. Filtrates containing bacilli, however, produce inflammatory 

 changes^ at the place of injection, and since the disease always develops in one 

 to two 'days, Lourens ' findings are in no way sufficient to weaken the importance 

 of the results obtained with fresh blood and filtrates of organs, or to shake general 

 belief in the correctness of recent discoveries. Moreover McBryde found recently 

 that the bacillus suipestifer may pass through some of the Berkefeld filters, but 

 not Chamberland B and i'', which however allow the hog cholera virus to pass. 



The same applies to the theory of Schreiber, according to which the blood of 

 hogs affected with hog cholera supports, through the agressins which it contains, 

 the pathogenic action of the bacillus suipestifer, or mobilizes the same, the bacillus 

 being a frequent habitant of the intestines of hogs. This theory stands in contra- 

 diction to the fact that even small quantities of blood, and especially from hogs 

 which have not yet developed intestinal changes, produce the disease, and further 

 that artificial infection may also result from feeding such blood, and that antiformin- 

 blood mixtures prove effective, in spite of the fact that the endotoxins of the 

 bacillus suipestifer are destroyed by this product. 



The view that the bacillus suipestifer plays only a secondary part 

 in the etiology of hog cholera is further substantiated by the discovery 

 that bacilli which morphologically, culturally, and biologically corres- 

 pond to the bacillus suipestifer not infrequently occur in the intestines 

 of entirely healthy hogs ; thus Garbert succeeded in demonstrating such 

 in seven out of 23, Uhlenhuth in 8.4% of 600 healthy hogs. Similar 

 results are also reported by Morgan from England, Gardenghi from 

 Italy, and Velzen from Holland. Furthermore Titze & "Weichel found 

 organisms in the intestinal contents of calves affected with white scour, 

 which absolutely corresponded to hog cholera bacilli, and also in one 

 healthy calf. 



The facts mentioned here,, as well as the experimental 

 observation that hogs which were inoculated with the filtrable 

 virus develop intestinal changes caused by the bacillus suipes- 

 tifer, lead to the belief that the bacillus suipestifer being a 

 frequent normal habitant of hog intestines, penetrates into the 

 tissues injured by the filtrable cholera virus, and exerts in the 

 same its pathogenic properties. 



