302 MICROBIOLOGY 



studied by Hueppe was B. lactis aerogenes. Other descrip- 

 tions show equal discrepancies. 



Staining. It stains with the ordinary aniline dyes. It 

 is Gram positive. 



Cultivation. It is cultivated without difficulty on cer- 

 tain of the ordinary media. 



Agar. There is no growth, or one that is scarcely visible. 

 On milk agar it grows rather better, but at best it is very 

 scanty. 



Gelatin stab. A granular or linear needle growth, and 

 no surface growth. Colonies are small points, rather opaque, 

 not characteristic. They are almost wholly under the surface, 

 and never grow typically on the surface. In litmus gelatin 

 they are rather dense, strongly acid, and frequently, though 

 not always, surrounded by minute, irregular spines along the 

 edge. This type of colony can usually be detected with a little 

 experience. 



Bouillon. Frequently there is no sign of growth in this 

 medium, but there is commonly a slight sediment. All three 

 (dextrose, lactose and saccharose) sugar bouillons are ren- 

 dered acid and there is commonly in the fermentation tube a 

 growth in the closed branch. 



Milk. Milk is rendered strongly acid and curdled in 

 from six hours to two days. The curd is smooth and hard, 

 without gas bubbles. The coagulated casein is not digested. 



Life conditions and properties. It grows best at about 

 20 C. although it will multiply at the body temperature. It 

 is a facultative aerobe, growing better without oxygen. No 

 toxins are described. It is not pathogenic for animals. The 

 above mentioned authors have described four distinct varieties 

 of this organism. 



BACTERIUM ( BACILLUS) BULGARICUM GRIGOROFF. 



Synonyms. Bacillus of Massol; B. ocidophilus ; Boas- 

 Oppler bacillus; Bacillus panis fermentati; Streptobacillus 

 lebcnis; Leptothrix buccalis. 



Place in nature. This organism was discovered by 



