268 Hog Cholera. 



forms, that is the cases which were heretofore considered as results 

 of two entirely different infectious diseases, are etiologically due to 

 one primary cause, namely to the infection of the body by the cholera 

 virus. 



At the present time it cannot even be imagined in what way the 

 filterable virus exerts its pathogenic action; on the other hand the 

 pathogenicity of the bacillus suipestifer and the bacillus suisepticus 

 is (juite well understood. Regarding the first one it must be accepted 

 that as a rule it penetrates into the follicles of the already catarrhal 

 intestinal mucous membrane, where it produces a cellular infiltration 

 of the follicles, Avith which a necrosis of the tissues soon becomes 

 associated. In this manner nodules first develop, then small, deep 

 round ulcerations covered with caseous material, Avhich gradually 

 become larger. At the same time usually, l)ut in some instances quite 

 independently, a necrosis of the epithelium and of the superficial layers 

 of the mucous membrane results from the immigration of the bacilli 

 into the lymi)li spaces of the mucous membrane, whereupon diphtheritic 

 or croupous inflammation results. Such deposits also develop very fre- 

 quently on the mucous membrane of the stomach, and of the pharj'ux. 



From the intestinal wall the bacilli pass through the lymph vessels 

 into the mesenteric lymph glands, where they produce a cellular infiltra- 

 tion, and conseciuently a tissue necrosis, as a result of which dry caseous 

 areas develop in the enlarged glands. In chronic cases the process 

 may remain confined to the intestinal wall and to the mesenteric lymph 

 glands, and may by disturbing the digestion finally result in complete 

 exhaustion of the animals. 



In other cases the bacilli may be disseminated along the lymph 

 'vessels, to distant lymph glands and into the blood circulation. The 

 infection of the blood may sometimes occur in the early stages, and 

 contribute to the aggravation of the already existing septic condition. 

 Besides bacillary emboli may cause the development of metastatic 

 inflammatory lesions, which will later caseate beginning at the center 

 (such caseated areas are most frequently found in the lungs, kidneys, 

 spleen and the liver). 



The necrosis (caseation) which is quite characteristic of hog cholera, 

 is probably to some extent the result of an obstruction of the blood 

 vessels by masses of bacilli, and the consequently developing nutritive 

 disturbances. In the first place however it is probably due to the 

 toxic action of the bacilli. 



Up to the present time experiments for the demonstration of toxins in cul- 

 tures of the bacillus suipestifer have not given uniform results. While Preisz found 

 that neither inactivated cultures nor bacteria-free filtrates of cultures were toxic for 

 test animals, Voges and Karlinski claimed that the killed bacteria contain an 

 intracellular toxin (according to Voges 10 mg. of killed bacteria are fatal to guinea 

 pigs). De Schweinitz produced a ptomaine from cultures by precipitation with 

 alcohol (Sucholotoxin) and also a poisonous albumose (Sucholoalliumin). He fur- 

 ther found two kinds of enzymes in aqueous extracts of agar cultures, as well as 

 in milk in which the liacilli were grown for three weeks, of which the one converts 

 starch into dextrose (Diastase), while the other liciuefies gelatin and digests fibrin 

 and albumen (trypsin-enzym). Prettner also found in the cultures bacteriolytic 

 enzymes, which slowly dissolve gelatin. According to the investigations of Prett- 

 ner and Emmerich the bacillus produces nitrous acid in material containing nitrates, 

 as well as in the intestinal canal, which may cause a nitrite poisoning in the body 

 of the animal (cyanosis, necrosis of the intestinal epithelia, paralysis or gangrene 

 of the sympathicus, serous transudations in the intestinal lumen, formation of 

 niethemoglobin in the blood). F. Schmidt aimed to obtain specdfic substances from 

 cholera bacilli, by the use of Brieger 's method (suspension of cultures grown on 

 agar in water ami shaking) as well as through the method of Conradi (autolysis), 



