BY R, GREIG SMITH. 449 



portion of the medium. The latter becomes strongly greenish 

 fluorescent. The organisms are oval and measure 04 : 1-1-5 p. 

 They are actively motile. The stab in gelatine is filiform with a 

 flat, irregular, moist glistening, yellowish-white nail-head. The 

 upper part of the stab becomes tuberculate. No fluorescence of 

 the gelatine was observed. Milk was not coagulated and the 

 reaction remained neutral. 



Bacterium fluorescens mutabile, Wright. 



i. — This is a rod-shaped bacterium with rounded ends measuring 

 0*5 : 0-8-1 fi and is not coloured by Gram's method of staining. 

 It is actively motile. The stroke on agar is greenish-white and 

 moist glistening; the growth is luxuriant and quickly widens to 

 the sides of the glass at the bottom of the stroke. The agar 

 becomes strongly fluorescent. The gelatine in stab culture 

 becomes liquefied in a funicular manner : the liquefied portion is 

 turbid with floating floccules, and there is a yellowish-white 

 precipitate and film. There is no fluorescence of the medium. 

 Milk is coagulated and has an alkaline reaction. On potato, a 

 moist glistening, drab-coloured expansion covers the surface of 

 the medium. 



ii. — This organism is a trifle larger than the above and measures 

 0-6 : 1-1 -5 /j.. The stroke on agar is drier and whiter than i., that 

 is, it is less translucent. It is also less luxuriant in its growth 

 and not so strongly fluorescent. Otherwise the characteristics 

 are similar. 



The two organisms are closely allied to Bad. pyocyaneum, 

 differing mainly in fluorescence. They are best described by 

 Wright's designation, and one of them is probably identical with 

 his organism. 



Bacillus subtilis, Ehrenberg. 



The hay bacillus forms on agar slope a dull flat membranous 

 layer with an irregular lacerate and ciliate margin. The mem- 

 brane quickly spreads over the greater part of the agar surface. 

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