DESCRIPTION OF SPECIES 



397 



BACHjIjUS aureus ACIDI (Conn). 



Source and habitat — Milk. 

 Morphology — A bacillus ; -6 y- broad, 



•7 fx. long (occasionally longer). 

 Staining reaction — Ordinary stains. 

 Biology : cultural characters {includ- 

 ing biochemical features). 



Gelatine plates and tubes — Round 

 yellow colonies ; opaque if deep ; 

 transparent if on surface ; of an 

 orange colour ; non-liquefying ; in 

 stab-culture produces a dry pit 

 lined with an orange-yellow skin. 



Agar plates and tubes; potato — 

 Orange-yellow growth. 



Milk — Curdled in 2 to 4 weeks 

 into moderately hard curd which 

 is acid, showing no whey and no 

 peptonisation. 



Aerobic. 



Non-pathogenic. 



BACHiliUS AUREUS LACTIS, Nos. 1 

 and 2 (Conn). 



Source and habitat — Milk. 



Morphology — Bacillus, round ends ; 

 •5 M broad, -7 or i m long. No 

 chains, but two or three may adhere 

 together. 



Staining reaction — Ordinary aniline 

 stains. 



Biology : cultural characters {includ- 

 ing biochemical features). 



Bouillon — No. i produces an 

 orange-yellow tenacious scum on 

 clear bouillon. No. 2, a thick 

 tenacious scum which sinks in 

 flakes and produces a sediment. 



Gelatine plates and tubes — Yellow 

 colonies, dark or depressed centre. 

 No liquefaction. In stab-culture, 

 No. I, good growth with yellow 

 surface growth. No. 2, slight 

 growth with white surface growth. 

 Agar plates and tubes — No. i 

 produces a moist, thick, yellow 

 growth. No. 2, a smooth, white 

 growth, turning lemon colour. 



Potato — Abundant growth ; 

 yellow, or commencing white and 

 becoming yellow. 



Milk — No effect except formation 

 of a scum in both varieties. 



Aerobic. 



Non-pathogenic. 



BACILLUS AUREUS MINU- 

 TISSIMUS (Conn). 



Source and habitat — Milk. 

 Morphology — Rod ; -4 fi broad and 

 1-6 M long. Three or four may be 

 united together in threads (especi- 

 ally in bouillon). 

 Staining reaction — Ordinary aniline 



stains. 

 Capsule. 



Biology: cultural characters {includ- 

 ing biochemical features). 



Bouillon — A slight scum on uni- 

 formly clouded fluid. A yellow 

 sediment in a few weeks. 



Gelatine plates and tubes — Thin 

 irregular branching colonies. 

 Liquefaction in 2 days, with 

 yellow centre and irregular pro- 

 cesses extending into medium. 

 In stab-culture a deep, narrow 

 funnel with bright yellow sediment 

 and scum. 



Agar plates and tubes — An 

 orange-yellow growth, spreading 

 over whole surface. 



Potato — A dark orange growth of 

 deep colour. 



Milk — Becomes pasty and dark 

 coloured at 20^ C. Slight slimy 

 change. Reaction alkaline. 



Aerobic. 



Non-pathogenic. 



BACILLUS BBRNENSIS. 



Source and habitat — Emmenthaler 



cheese, producing aroma. 

 Morphology — Thick rods. 

 Staining reaction — Ordinary aniline 



stains. 



