XOX-PATHOGENIC BACILLI. 637 



around it acquires a pale-pink color, and after a time liquefaction occurs ; 

 along- the line of puncture the development is scanty ; at the end of ten to 

 twelve days a slightly clouded, pink liquid is seen at the upper part of the 

 test tube, ia which well-defined yellow colonies are suspended, while the 

 unliquefied gelatin below has a pink color. Upon the surface of agar a 

 glistening, yellowish layer is slowly developed. Upon potato development 

 is more rapid and an extended layer is formed, which is first grayish-white 

 and later yellow in color; the potato acquires a dark color which later 

 becomes yellowish -red ; at 37 C. , at the end of six to eight days, an intense 

 golden-yellow color is developed. In bouillon development is rapid and 

 yellowish cloudiness of the culture medium is seen. In milk the casein is 

 slowly precipitated and later is peptonized, with a neutral or alkaline re- 

 action of the medium ; a stratum of blood-red serum is seen above the pre- 

 cipitated casein, and above this a yellowish-white layer of cream. 



281. BACILLUS GLAUCUS (Maschek). 



Found in water. 



Morphology. Slender bacilli of various lengths. 



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

 bacillus. Produces a gray pigment. Spore formation not observed. Grows 

 rapidly in the usual culture media at the room temperature. Upon gelatin 

 plates forms round, gray colonies w T ith sharply defined outlines; on the 

 fourth day the centre becomes intensely gi*ay, th'e margin brown and folded 

 in a radial direction ; on the eighth day liquefaction has occurred and the 

 colony sinks beneath the surface. In gelatin stick cultures development is 

 rapid both upon the surface and along the line of puncture ; the entire gela- 

 tin is quickly liquefied and a gray deposit is seen at the bottom of the tube. 

 Upon the surface of agar a gray layer is quickly developed. Upon potato 

 the growth is at first of a dirty- white; later a slimy, dark-gray layer is 

 formed. 



282. BACILLUS LIVIDUS (Plagge and Proskauer). 



i 



Found in the Berlin water supply. 



Morphology. Slender bacilli of medium size. 



Biological Characters. An aerobic and facultative anaerobic, liquefy- 

 ing, motile, chromogenic bacillus. Produces an intense blue-black pigment. 

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

 the room temperature. Upon gelatin plates the colonies at first resemble 

 drops of ink ; the gelatin around them is slowly liquefied and a bluish- violet 

 deposit is seen at the bottom of the liquefied gelatin. In gelatin stick cultures 

 a colorless growth is seen along the line of puncture and a violet layer upon 

 the surface ; liquefaction occurs very slowly. Upon the surface of agar a 

 beautiful blue-black layer is developed. Upon potato an abundant layer of 

 a violet color is formed along the line of inoculation. 



283. BACILLUS INDICUS (Koch). 



Found in the contents of the intestine of a monkey, by Koch, while pur- 

 suing his cholera investigations in India. 



Morphology. A short and slender bacillus with round ends. 



Biological Characters. An aerobic and facultative anaerobic, liquefy- 

 ing, motile, chromogenic bacillus. Spore formation not observed. Produces 

 a brick-red pigment. Grows rapidly in the usual culture media best in the 

 incubating oven. Upon gelatin plates the deep colonies are white and 

 punctiform ; under a low power they are seen to be granular, irregular in 

 form, and of a greenish-brown color. The superficial colonies quickly cause 

 liquefaction of the gelatin and form circular depressions with a well-defined 

 outline and grayish contents, which under the microscope appear as dense, 

 finely granular, grayish-yellow masses, the edges of which appear to be 



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