QUALITATIVE BACTERIOLOGICAL ANALYSIS. 63 



B. Aquatilis (Percy Frankland). 



This organism was found by Percy and G. C. Frankland in 

 water obtained from deep wells sunk in the chalk by the Kent 

 Company. It is very similar in appearance to the B. arborescens, 

 forming long wavy threads sometimes as long as 17 JJL ; spores 

 are not observed and the movement is only vibratory. In 

 gelatine plates the colonies in the depth at first appear smooth- 

 rimmed, but the contour gradually becomes more and more 

 irregular ; on reaching the surface slow liquefaction of the gelatine 

 commences and convoluted bands of threads extend from the 

 centre to the periphery. In gelatine tubes it grows extremely 

 slowly ; a yellow expansion forms on the surface but hardly any 

 growth appears in the depth ; later slight liquefaction takes 

 place. On agar there is a small, shining, yellow growth. Broth 

 is rendered turbid ; there is a white deposit, but no pellicle forms 

 on the surface. On potato there is hardly any growth. In 

 nitrate broth there is a good growth but the nitrates are not 

 reduced. 



B. Aquatilis. 



In water supplied by the Kent company, I have frequently 

 found a bacillus which appears to be closely allied to the 

 B. aquatilis of Frankland. The colonies of this organism in 

 gelatine plates appear at first as delicate circular films, which 

 under a low power show a series of concentric rings ; later lique- 

 faction of the gelatine slowly sets in and under a lower power 

 the concentric rings are not so marked, but a mass of convoluted 

 bands, passing outwards from the centre, are now seen, and the 

 margin appears set with wedge-shaped processes. In gelatine- 

 stab there is a cup-shaped liquefaction, the surface being covered 

 with a folded membrane. On agar there is yellowish, very 

 sticky, growth. Milk is not coagulated. In glucose and lactose 

 media, there is no gas formation. In peptone solution, after 

 incubation for seven days at 37 C., there is a slight indol 

 reaction on adding potassium nitrite and a few drops of pure 

 sulphuric acid. Litmus-whey, after twenty -four hours at 37 C , 

 is rendered strongly alkaline. Nitrate-broth is not reduced. 

 Potato shows a yellow, limited growth. In broth there is a 



