Pyobacillosis of Hogs. 143 



The cultivation, although somewhat difficult, succeeds aerobically 

 as well as anaerobically, but only at temperatures of between 24 and 

 40°C., (the best growth being obtained at 37°C.), and only in the 

 presence of proteid. As nutritive media coagulated horse, cattle or 

 hog blood serum is most suitable on the surface of which fine bluish 

 points, and corresponding with these through liquefaction of the 

 medium, small cup-shape depressions develop in from 2 to 7 days. 

 Stab cultures in coagulated serum show a grayish thread consisting 

 of little round colonies or a continuous growth, which, after liquefac- 

 tion of the serum, soon sink down and form a flaky gray mass. On 

 serum agar small transparent drop-like colonies develop in the stab 

 which confluate, forming a lustrous transparent thin layer. On serum 

 agar plates the colonies form small thorn apple-like and later round 

 colonies. Luxuriant growth is obtained in milk which commences to 

 coagulate from the bottom up in 48 hours, and finally turns to a 

 uniform whey from which a water-clear serum separates later. 



The resistance of the bac. pyogenes is very slight. In cultures it does not re- 

 main active longer than from 2 to 3 months. A temperature of 57 "C, drying, for- 

 malin vapors or sulphuric acid kill it rapidly. (Piitz, Berger). 



According to the investigations of Grips, Glage & Nieberle the 

 pathogenic characteristics of the organism develop in small test animals 

 only after the injection of large doses of cultures, in which case they 

 produce suppurative processes. In sucking pigs the feeding of pure 

 cultures produces a chronic gastro-intestinal catarrh, which, especially 

 during weaning time, results in fatal diarrhea. In addition atelectasis, 

 exudative pleurisy and peritonitis as well as nervous attacks may de- 

 velop not infrequently. The animals which recover from the disease 

 remain runts. Intratracheal injection produces suppurative bronchitis. 

 Subcutaneous injection causes a spontaneously perforating abscess at 

 the point of inoculation. In older weaned pigs the action of the inocula- 

 tion is manifested in similar changes, only that in this case also skin 

 lesions in the form of pox-like eruptions and scabs are frequently 

 observed. Intrapulmonary injections result in catarrhal pneumonia,, 

 exudative pleuritis or abscess formations surrounded by a hepatized 

 area. Metastatic lesions may develop in the joints. Intrapleural in- 

 jections cause a specific pleuritis with catarrhal pneumonia in the ad- 

 joining lung tissue, as well as chronic pericarditis. Intraperitoneal 

 injections produce a specific peritonitis, while intravenous injections 

 result in a fatal pyemia. Healthy pigs which are placed in contact 

 with experimentally infected animals become stunted in growth as a 

 result of chronic gastritis. 



The later experiments of Piitz, Berger & Holth gave practically 

 the same results, as they have proved that the pyobacillus produces 

 suppurative inflammation in the animal tissues, which is characterized 

 by its chronic and slow character. A marked prolification similar to 

 the condition occurring in actinomycosis, precedes the breaking down 

 of the tissues (Holth). The authors mentioned above failed in pro- 

 ducing catarrhal pneumonia in hogs by inhalations or tracheal in- 

 jections of cultures. 



According to these experiments the diseased condition occurs in 

 hogs, especially in young pigs, principally associated with suppurative 

 processes. They are caused by specific bacilli and may be artificially 

 produced in healthy animals. The nature of the anatomical changes 



