450 MICRO-ORGANISMS IN WATER 



BACILLUS AQUATILIS (Percy Frankland) 



LIQUEFIES GELATINE 



Authority. — Percy and G. C. Frankland, Zeitschrift fllr Hygiene, vol. vi. 

 p 381. 



"ViTliere Found.— Found by the above in water obtained from deep wells sunk 

 into the chalk by the Kent Company. The Bacillus aquatilis a found in the 

 Dorpat water by Tataroli', and described by him in Die Dorpater Wasserhac- 

 iericn {Dorpat, 1891), is doubtless identical with the above. 



Microscopic Appearance. — Very similar in appearance to B. arborescens, 

 forming also long wavy threads, sometimes as long as 17 /j. and more. No 

 spores observed. Vibratory movement only. 



Cultures. — 



Gelatine Plates. — In the depth the colonies at first appear smooth-rimmed, 

 but the contom' gradually becomes more and more irregular. On reaching the 

 surface alow liquefaction of the gelatine commences, and convoluted bands of 

 threads extend from the centre to the periphery. 



Gelatine Tubes. — Grows extremely slowly ; forms a slightly yellow expan- 

 sion on the surface, but hardly any growth appears in the depth. Later slight 

 liquefaction takes place. 



Agar- AGAK.— Produces a small shining yellow growth. 



Broth. — Renders it turbid, and produces a whitish deposit. No pellicle is 

 formed. 



Potatoes. — Hardly any growth at all. 



fiemarks. — When introduced into the nitrate solution (sfie p. 27) it grows abun- 

 dantly, but fails to convert the nitrate to nitrite. 



BACILLUS AQUATILIS 



Authority. — Lustig, Diagnosiik der Bakierien des Wassers, 1893, p. 67. 



Where Found.— Found by Lustig and Carle somewhat frequently in various 

 waters — river, stream, spring, and stagnant water— obtained from the Aosta 

 valley. 



Microscopic Appearance.— Short, straight bacillus, three times as long as 

 broad, with rounded ends. Occurs singly, and occasionally several bacilli hang 

 together forming filaments. Exhibits lively pendulum-like movements. No 

 spore formation was observed. Is coloured with the ordinary stains, but will 

 not stain by Gram's method. 



Cultures. — 



Gelatine Plates.— After forty-eight hours white dots resembling mother-of- 

 pearl appear on the surface as well as in the depth. The superficial colonies are 

 round, and give rise to convex pin-head shaped projections. Under the micro- 

 scope, with a low power, the edges look sharp and regular, and the contents 

 granular and yellow. The colonies do not extend with age, but only become 

 more raised. The gelatine is not liquefied. 



Litmus Gelatine. — Grows similarly, but more quickly. The gelatine does 

 not change colour even after months. 



Broth.— Renders it turbid at room-temperature. 



Agab-agar. — Produces a white, moist expansion, but only grows at the tem- 

 perature of a room. 



Potatoes. — Grey white expansion, having a smeared appearance, with 

 irregular contour ; after six days the growth becomes of a coffee-yellow colour. 



Kemarks. — It grows rapidly even in the absence of air, but will not de velop at a 

 liigher temperature than from 23° to 25=* C. It grows luxuriantly in ammonia solutions 

 \vithout oxidation. It reduces nitrates to nitrites. 



