NON-PATHOGENIC BACILLI. 681 



of agar a whitish, rosette-like layer is developed. Upon potato forms a 

 transparent, gum-like layer, which later is thrown into thick, soft folds, 

 similar to the growth of Bacillus mesentericus vulgatus. In milk causes co- 

 agulation of the casein, winch at 30 C. is precipitated as a whitish, cloudy 

 sediment, above which a clear serum is seen ; the casein is subsequently 

 peptonized. 



387. BACILLUS ULNA (Cohn). 



First described by Cohn, and subsequently found by Prazmowski in a 

 solution of egg albumin. 



Morphology. Bacilli of 1.5 to 2.2 ju in breadth and of various lengths at 

 least 3 M ; forms long, jointed filaments; forms spores which are 2.5 to 2.8 n 

 long and 1 /* broad. 



Biological Characters. An aerobic, motile bacillus which is said to 

 grow only in albuminous solutions (?), in which it develops as cloudy masses 

 w r hich collect at the surface and form a thick, dry mycoderma consisting 

 of long, interlaced filaments in bundles and irregular aggregations ; does not 

 give on a putrefactive odor. Imperfectly described. 



388. BACILLUS ULNA OF VIGNAL. 



Found by Vignal in the salivary secretions of healthy persons, and sup- 

 posed to correspond with Bacillus ulna of Cohn. 



Morphology. Straight bacilli with round ends, about 2 u long ; often 

 united in pairs, in which the elements are strongly adherent; rarely in 

 chains containing more than two segments. 



Biological Characters . An aerobic, liquefying bacillus. Spore forma- 

 tion not observed. Motility not mentioned. Upon gela- 

 tin plates, at the end of twenty-four hours, small, gray- 

 ish superficial colonies are formed ; the centre of these 

 is thicker than the periphery; under the microscope the 

 peripheral zone is seen to be made up of fine interlaced 

 filaments ; by the second or third day the colonies have 

 increased considerably in size, and a small, grayish- 

 white, opaque mass is seen, which is surrounded oy an 

 extended zone of liquefied gelatin ; this is seen to con- 

 sist of four secondary zones : next the central mass the 

 gelatin is almost transparent, outside of this is a granular FIG. 227. Bacillus 

 zone, outside of this a grayish, less granular zone, and ulna of Vignal, from a 

 finally an outer zone which is almost transparent. In culture in nutrient 

 gelatin stick cultures, at the end of forty-eight hours, agar. x i.soo. (Tig- 

 liquefaction in funnel form has occurred along the line nai.) 

 of puncture ; the liquefied gelatin is transparent and con- 

 tains suspended opaque, white flocculi, which accumulate at the bottom ; by 

 the fourth day the gelatin is completely liquefied as far as the inoculating 

 needle penetrated, and a whitish film is seen upon the surface. Upon the 

 surface of agar a very adherent, white layer is developed which presents 

 punctiform and linear depressions ; the agar below acquires a slightly brown- 

 ish color. In bouillon the liquid remains transparent and acquires a yel- 

 lowish tint, while a tolerably thick, fragile, smooth, white mycoderma is 

 formed upon the surface ; rather a scanty white deposit accumulates at the 

 bottom. Grows in acid bouillon 1 :2,000 of hydrochloric acid. Upon po- 

 tato a thin, grayish-white layer is formed at the end of forty-eight hours, 

 upon the surface of which fine, slightly elevated lines cross each other in all 

 directions ; sometimes this forms quite regular hexagonal figures Blood 

 serum is liquefied by this bacillus. All the cultures have a disagreeable 

 odor, similar to that given off by Bacillus pyogenes fcetidus. 



