916 ON THE EXAMINATION OF WATER FROM THE SYDNEY SUPPLY, 



their central parts. With very active spontaneous movements 

 which exhibit themselves as a tremulous hurrying across the 

 field of the microscope, and are especially extremely vivid in the 

 immediate neighbourhood of air-bubbles in a drop of water under 

 the cover-glass (aerobic bacterial form.) 



On gelatine-plates. It forms at the surface of the gelatine 

 greyish, turbid-looking colonies of circular circumference (Pis. 

 X, XI, figs. 1, 3, 4, a), which exhibit, when examined with low 

 magnifying powers, granular contents. The colonies enlarge very 

 rapidly, liquefying at the same time and at the same rate the 

 gelatine, effecting in the latter, at first, funnel-shaped, then with 

 the advancing growth of the micro-organism, watch-glass-like 

 excavations now filled with liquid matter. In the interior of the 

 layer of gelatine the colonies multiply much more slowly than do 

 the superficial ones. 



When quite young — of from -Ol-*^ mm. diam. — the colonies 

 present, in optical section, more or less perfect circle-figures, 

 with smooth outlines, as indicated by a bright, black, uninterrupted 

 line, and showing a greyish colour. Contents of the vegetations 

 homogeneous, slightly granular. In the larger ones signs of a 

 commencing liquefaction of gelatine are visible. 



In nutrient gelatine in a test-tube this bacillus displays a vigorous 

 propagation which results in the production, in a proportionately 

 short time, and along the track of the inoculating platinum wire, 

 of an inverted conical bag of liquefied gelatine. The growth 

 rapidly spreads itself in the gelatine, forming at the bottom of the 

 conical-shaped or forefinger-like excavation of the latter a granular, 

 rather dense deposit, whilst in the superincumbent liquid, which 

 offers a turbid greyish appearance, small granules and particles are 

 distributed. In course of time, the whole contents of the test- 

 tube become one liquid mass. 



On a sloping surface of nutrient agar-agar in a test-tube this 

 bacillus readily grows laterally from the streak of the inoculation, 

 and ultimately represents a greyish-white, shining, gelatinous, 



