444 PATHOGENIC AEROBIC BACILLI 



" Action on Milk. Coagulated into a gelatinous coagulum in twenty- four 

 hours at 38 C., and into a solid clot in two days. 



" Milk Litmus Reaction. Milk colored blue with litmus is changed to 

 light pink in twenty-four hours at 38 C. The pink color gradually fades, 

 and by the second or third day is white or cream color with a thin layer* of 

 pink on top. The pink color extends in a few days about one-half down the 

 clot. 



" Temperature. Grows best about 38 C. 



' ' Spores have not been observed. 



" Gas Production. Gas bubbles are produced in milk ; not observed on 

 potato. " 



BACILLUS 6 OF BOOKER. 



' ' Found as the predominating form in two cases of dysentery one of 

 which was fatal and the other a mild case. 



" Morphology. Resembles Bacterium coli commune. 



" Growth in Colonies. Gelatin : The colony growth varies considerably 

 with slight difference in the gelatin. In ten-per-cent neural gelatin the colo- 

 nies resemble those of Bacterium coli commune. On the second or third 

 day, when the colonies have just broken through the surface and are spread 

 out, it is impossible to distinguish one variety from the other, but as the 

 colonies grow older a difference can generally be recognized. In sugar and 

 acid gelatin the colonies have a clear centre with white border ; slightly 

 magnified, a uniform brown centre surrounded by a brown zone composed 

 of fine, needle-like rays perpendicular to the border. After cultivating for a 

 few generations on acid and sugar gelatin the colonies cease to develop, and 

 either grow in very small colonies or do not grow at all. The activity is re- 

 gained if cultivated on neutral gelatin. 



' ' Agar : Colonies are large, round, and have a mother-of-pearl appearance. 

 Slightly magnified, a uniform yellow color. 



" Stab Cultures. Agar: Luxuriant, nearly colorless surf ace growth, with 

 well-developed stalk along the line of inoculation in the depth. 



'"Potato: Golden- yellow, glistening, slightly raised surface with well-de- 

 fined borders. 



' ' Action on Milk. Milk becomes gelatinous in twenty-four hours at 38 C. , 

 and in a few days a solid coagulum is formed. Milk colored blue with lit- 

 mus is reduced to white or cream color in twenty-four to forty -eight hours 

 at 38 C., with a thin layer of pink at the top of the culture. The pink color 

 gradually extends lower in the coagulum. 



' Temperature. Thrives best at about 38 C. 

 ' Spores have not been observed. 



' Gas Production. Occurs in milk, but not seen in potato cultures. 

 ' Relation to Gelatin. Does not liquefy gelatin. 



' Resemblance. Resembles Bacterium coli commune and bacillus d ; dif- 

 fering from the former in the character of the colony growth on acid and 

 sugar gelatin, and in ceasing to develop in these media after several genera- 

 tions. It differs from bacillus d in this latter respect." 



BACILLUS / OF BOOKER. 



" Found in one case of cholera infantum and one case of catarrhal ente- 

 ritis. 



"Morphology. Resembles Bacterium coli commune. 



" Growth in Colonies. Gelatin: It is difficult to distinguish the colony 

 growth from the Bacterium coli commune. There is often a difference in the 

 colonies planted at the same time and kept under similar conditions, but it 

 is not very marked nor always the same kind of difference. The tendency 

 to concentric rings is greater in this variety. The colonies develop some- 

 what better on neutral and sugar gelatin than on acid gelatin. 



