ANOMALOUS FERMENTATIONS 201 



distinctive sickly sweetish odour. The red coloration will not 

 occur if the milk is exposed to light or has an acid reaction. The 

 Bacillus ladis erythrogenes of Hueppe (Bacterium erythrogenes of 

 Grotenfeldt) is an aerobic, liquefying, non-motile, non-sporing, 

 chromogenic bacillus of 1 to 1-5 mm. in length by -3 to -4 mm. in 

 breadth, at times attaining, especially in broth cultures, a length of 

 4 to 5 mm. in the form of filaments. It takes readily all ordinary 

 stains and holds the Gram. In sterile milk a gradual precipitation 

 of the casein takes place with a neutral or slightly alkaline reaction 

 of the medium. The resultant serum, in the absence of light, absorbs 

 the red colouring matter produced by the organisms, taking a deep 

 red tint provided the medium has no acid reaction. The coagulation 

 by rennet of mUk infected with the organism has the effect of 

 producing a marked dirty red coloration, changing to a reddish- 

 brown and finally to blood red. 



Blue Milk is due to the growth of the Bacillus cyanogenes 

 (Bacterium syncyaneum of Ehrenberg), or as Hueppe originally 

 termed it, the Bacillus lactis cyanogenus, an anaerobic, non-liquefying 

 bacillus, motile, bi-polar, flagellated, chromogenic, and round-ended, 

 with a varying average length of from 1 to 4 mm. by -3 to -5 mm. in 

 breadth. Spore formation has been claimed by Hueppe, but 

 denied by Heim, who describes the so-called spores of Hueppe as 

 involution forms only. In liquid cultures curious involution forms 

 are often observed, which are especially noticeable if the organism is 

 grown in mineral media, as those of Conn and Nsegeli. The organism 

 does not liquefy gelatine and grows freely on all the usual laboratory 

 media at room temperature, the dark purplish blue or in some cases 

 brownish coloration of the medium being very characteristic, but 

 this freedom of growth becomes less as the temperature advances to 

 37° C, and the cultures themselves die at 40°. The reaction is 

 invariably alkaline, although the medium itself may have been in the 

 first place acid. It stains well with all the ordinary stains but does 

 not hold the Gram. In milk the bluish tint would appear to be 

 dependent upon certain unknown conditions, and in the sterile milk 

 ixsed for the laboratory purposes it is not easy to obtain it. 



Yellow Milk. — Bacillus synxanthus is held responsible for curdling 

 the milk, and then at a later stage, in redissolving the curd, produces 

 a yellow pigment. 



In addition to the bacteria of fermentation occasionally present 

 in milk, there is a group of Various Unclassified Bacteria. In 

 milk this is a comparatively small group, for it happens that 

 those bacteria in milk which cannot be classified as fermentative or 

 pathogenic are few. B. coli communis occurs here as elsewhere, 

 and might be grouped with the gaseous fermentative organisms on 

 account of its extraordinary power of producing gas and breaking up 



