NOT DESCRIBED IN PREVIOUS SECTIONS. 499 



Stains with the usual aniline colors. 



Biological Characters. An aerobic, non-liquefying, motile bacillus. 

 Forms spores. Grows at the room temperature in the usual culture media. 

 Upon gelatin plates the colonies are spherical or oval and of a light-brown 

 color ; under a low power they are seen to be finely granular, and later have 

 a dark-brown color. Upon the surface of gelatin stick cultures a grayish- 

 white layer is formed ; but slight development occurs along the line of punc- 

 ture. Upon the surface of agar a thick, gray layer forms along the line of 

 inoculation. Upon potato yellowish, glistening, dew-like drops are first 

 formed along the line of inoculation, and later a rather thick, brownish 

 layer is formed which extends rapidly over the surface. Development is 

 most rapid in the incubating oven. 



Pathogenesis. According to Afanassiew, pure cultures injected into the 

 air passages or pulmonary parenchyma, in young dogs or in rabbits, produce 

 bronchial catarrh, broncho-pneumonia, and attacks of spasmodic coughing 

 resembling those of whooping cough. Death sometimes occurs. At the 

 autopsy the bacillus is found in great numbers in the bronchial and nasal 

 mucus. 



120. PNEUMOBACILLUS LIQUEFACIENS BOVIS. 



Obtained by Arloing from the lung of an ox which succumbed to 

 infectious pleuro-pneumonia. 



Morphology- Slender, short bacilli, which rather resemble mi- 

 crococci when cultivated in gelatin. 



Stains with the usual aniline colors. 



Biological Characters. An aerobic and facultative anaerobic, 

 liquefying, non-motile bacillus. Spore formation not observed ; is 

 killed by exposure for fifteen to twenty minutes to a temperature of 

 55 C. Grows in the usual culture media at the room temperature 

 better at 35 C. Forms white colonies in gelatin plates, and 

 causes rapid liquefaction of the gelatin. Upon potato grows very 

 rapidly as a white layer, which later has a brownish color. 



Pathogenesis. From one-half to one cubic centimetre of a pure 

 culture injected beneath the skin of an ox, where the connective tis- 

 sue is loose, causes the development of an acute abscess the size of a 

 man's hand ; after extending for two or three days this gradually 

 becomes smaller and recovery occurs. When larger quantities are 

 injected a fatal termination may result. Guinea-pigs and rabbits 

 are less susceptible, and dogs are said to be immune. 



The researches of Arloing seeem to have established the etiologi- 

 cal relation of this bacillus to infectious pleuro-pneumonia of cattle. 

 Arloing has shown (1894) that inoculations in cattle of pure cultures 

 of the bacillus are followed by immunity quite as pronounced as that 

 resulting from inoculations with serum from the lungs of diseased 

 animals method of Willems ; also that infected animals are more 

 sensible to the action of the toxic substances in filtered cultures than 

 healthy animals corresponding with results obtained by use of tu- 

 berculin and mallem. 



Arloing has obtained two varieties of his bacillus from the lungs 

 of cattle, one an attenuated variety which does not liquefy gelatin. 



