Etiology Pathogenicity. 127 



lungs and lymph glands), and also grows somewhat better 

 anaerobically than do the other varieties of this organism. 



Tenacity. In distilled water the bacilli retain their virulence up to 14 days; 

 heating for % of an hour to 5S° C. kills them in 20 minutes, direct sunlight in 6 

 to 8 minutes, diffused daylight in about one hour (Joest). Exudate dried on silk 

 threads loses its virulence in daylight after 48, in darkness after 72 hours. In 

 sterilized milk the virus retains its virulence for 14 days, in sour milk not more 

 than a few days. In hog and cow manure, at a depth from 20 cm. to 1% m., they 

 remain alive for about 14 days (Beck & Koske). Disinfectants have an effective 

 action on the organism even in mild solutions. Thus their development is checked 

 by carbolic acid 1:2000, sulphuric acid 1:5500, potassium hydrate 1:900; while 

 corrosive sublimate 1:15000 as well as %% creolin solution destroys the bacteria 

 in one minute, 1% copper sulphate solution in three, 1% solution of lime water and 

 chlorate of lime in 20, 1:2000 formalin in 40, lastly iron sulphate solution in 40 

 minutes. (Erdos & Koppanyi.) 



Pathogenicity. The virulence of various strains of the 

 bacillus varies within very wide limits and changes sometimes 

 very rapidly even in cultures of the same strain. Aside from 

 hogs, animals susceptible to artificial infection are mice, rabbits, 

 guinea pigs and domestic fowl. All animals of these species 

 succumb to a subcutaneous infection of 0.1 to 0.5 cc. of bouillon 

 culture inside of 24 hours, dying of septicemia. Rabbits are 

 especially susceptible, and they are killed in 36 hours by 0.1 

 cc. of a bouillon culture diluted to a trillionth part (Preisz). 

 Some strains are so much less virulent, that they kill guinea 

 pigs injected intraperitoneally and rabbits intravenously only 

 with difficulty, and are altogether harmless for chickens, which 

 may, however, develop a chronic affection of the joints (Lig- 

 nieres). Carnivorous animals succumb to intravenous infec- 

 tions. In large animals a subcutaneous injection results in a 

 local inflammatory process (calves, however, may die), while 

 intravenous injections result occasionally in death. Feeding of 

 cultures is not as effective, but rabbits may easily be affected 

 by this method. After repeated inoculation horses develop a 

 diseased condition with indications of a chronic intoxication 

 and interstitial hepatitis. 



Intrapulmonary injections cause multiple necrotic pneu- 

 monia in hogs (Schiitz), and sometimes this may also be pro- 

 duced by inhalation of a virulent culture (Scliutz, Olt, Putz, 

 Beck & Koske). Intertracheal injections of the culture have a 

 similar action (Lignieres, Karlinski), and intravenous injec- 

 tion produces a double pneumonia, pleurisy and pericarditis 

 (Smith). After subcutaneous injection in the thigh an inflam- 

 matory growth develops occasionally at the point of injection, 

 with which then a lymphangioitis becomes associated, where- 

 upon the animal dies in 4 to 5 days or may linger for several 

 weeks (in the latter cases not infrequently inflammatory mani- 

 festations of the different joints develop in addition to the 

 cachectic manifestations. Autopsy frequently reveals in acute 

 cases a necrotic pleuro-pneumonia with hemorrhages (Preisz). 

 In the majority of cases, however, the local inflammatory pro- 

 cesses subside, and the animal recovers, or the inoculation does 



