798 PATHOGENIC MICROORGANISMS 



B. Bronchiseptisus. Prior to 1910 a great deal of inconclusive 

 work was done on canine distemper, but in this year Ferry 7 published 

 a preliminary paper in which he reported the isolation of a bacillus 

 which was often present in pure culture in the smaller bronchii and 

 the tracheae of dogs killed early in the disease. At almost the 

 same time, and independently of Ferry, McGowan 8 reported similar 

 observations. Soon after this the subject was very thoroughly 

 studied by Torrey and Rahe. 9 The B. bronchisepticus was described 

 as a short, Gram-negative organism, occasionally coccoid in appear- 

 ance, slowly motile, which grows very slowly at first isolation, the 

 colonies being hardly visible on agar in twenty-four hours but 

 definitely visible in forty-eight hours. It grows well on glycerin 

 agar, will grow at 20 with an optimum at about 37.5. It is not 

 an obligate aerobe, but grows poorly without oxygen. It does not 

 liquefy gelatin. It renders broth uniformly turbid with a slight 

 deposit and no pellicle. No acid or gas is formed on carbohydrate 

 media, and the media are rendered slightly alkalin in the course of 

 four or five days. Torrey could determine no indol formation. The 

 typical media, according to McGowan, Ferry and Torrey are litmus 

 milk and potato. Torrey states that the use of these two media 

 alone is sufficient for identification in the hands of a practiced 

 observer. 



On litmus milk it grows like the B. fecalis alkaligenes. There 

 is a progressive alkalinization, and after about twenty-four hours 

 at 37 a ring of deep blue appears, extending about 3/8 inch from 

 the surface. In from five to ten days the whole medium has assumed 

 a blue-black color. On potato in twenty-four hours a marked yel- 

 lowish-brown growth appears with sometimes a greenish darkening 

 of the potato. In this respect again it is very similar to B. fecalis 

 alkaligenes. Torrey also reports that the organism produces a 

 hemolysin for rabbit and guinea pig erythrocytes. He states 

 that typical distemper can be induced in susceptible dogs by injec- 

 tion with pure cultures, and dogs which have recovered from attacks 

 induced by the bacillus are protected by exposure to the disease in 

 other dogs. 



7 Ferry, Amer. Veterinary Review, 499, 1910 (quoted from Torrey) Jour. Infec 

 Dis., 8, 1911, 399. 



8 McGowan, Jour. Path, and Bacter., 15, 1911, 372 and 1916, 257, 



9 Torrey and Rahe, Jour. Med. Res., 27, 1912, 291. 



