470 PATHOGENIC AEROBIC BACILLI 



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 li^ht-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 1 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 an in- 

 fectious form of pneumonia. 



Morphology. Slender, short bacilli, which rather resemble micrococci 

 when cultivated in gelatin. 



Stains with the usual aniline colors. 



Biological Characters. An aerobic and facultative anaerobic, liquefy- 

 ing, non-motile bacillus. Spore formation not observed ; is killed by ex- 

 posure 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 tissue 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. 



121. BACILLUS PSEUDOTUBERCULOSIS. 



Obtained by Pfeiffer (1889) from the organs of a horse suspected of hav- 

 ing glanders and killed. 



Morphology. Rather thick bacilli with round ends ; vary considerably 

 in length usually three to five times as long as broad. 



Stains with f uchsin and Lofner's solution of inethyleiie blue ; does not 

 stain by Gram's method. 



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

 lus. Spore formation not observed. Grows in the usual culture media at 

 the room temperature. Upon gelatin plates, at the end of twenty-four 

 hours, the superficial colonies are small, yellowish-brown plates, which in- 

 crease rapidly in diameter ; under a low power a central papilla is observed, 

 around which the colony extends as a pale-yellow, peculiarly marbled, crys- 

 talline disc ; the deep colonies are at first transparent, sharply defined spheres ; 

 on the third day, under a low power, they are seen to have a dark, finely 

 granular central portion surrounded by a transparent zone ; when not 

 crowded upon the plate they may appear as yellowish-brown, finely granu- 

 lar, pear-shaped or lemon-shaped colonies. In gelatin stick cultures growth 

 occurs along the line of puncture in the form of grayish-white, spherical 

 colonies, more or less crowded above, and often isolated below, where by 



