68 Ward. — A Violet Bacilhis fro7n the Thames. 
around by this time. Liquefaction may be complete, or soon 
arrested. Submerged colonies may remain yellowish, or only 
become faintly coloured : the exposed ones become deep blue- 
violet, and all stages to white may occur on the same plate. 
Streak-culture At 15 0 C. forms a white, opaque, milky streak in 24-48 hours. 
on gelatine. 
In three days may show signs of sinking as gelatine softens, and 
violet hue may begin to appear along the axis. In nine or ten 
days the gelatine is scooped, and a violet membrane floats on the 
liquefied mass, in which violet and dirty-white flecks are dis- 
tributed. More or less complete liquefaction of the gelatine 
follows, but it often requires many weeks, even at 20° C., for 
completion throughout the tube. 
Stab-culture in In three days at 15 0 C. a small white button, like a drop of 
gelatine. 
milk, is formed at the point of inoculation, and minute white 
points in the tunnel. In ten days or so the button has sunk 
in a depression of liquefied gelatine, producing a thistle-head 
funnel. Culture still white. In eighteen days the liquefaction 
reaches nearly to the walls of the tube, the funnel being lined by 
a violet membrane. In about four weeks the gelatine is liquefied 
to'* one-eighth of its depth or so, a deep violet, folded membrane 
floating on the top and through the liquid. , At 20° C. the same 
phenomena are observed, but proceed more rapidly at first. It 
takes many weeks or even months to completely liquefy all the 
gelatine. Submerged in gelatine : no growth. 
Agar. 
Forms a thick white streak in 24-48 hours at 20° C. which 
turns violet along the axis on the fourth day or later. In about 
ten days a magnificent corrugated, deep violet membrane is formed, 
which can be lifted, and shows white growth below. When 
water of condensation is collected, the submerged growth is white. 
Potato. 
In from two to five days, at 20° C., a more or less copious, dirty- 
white to yellowish patch. Later on the violet colour spreads from 
the centre, and a corrugated, deep violet membrane is found by the 
tenth day. But this often does not extend to the edges, and in 
some cases fails altogether. 
Broth. 
Traces of turbidity in two days at 20° C., and by the sixth day 
very turbid, especially towards the top, where a thick white mem- 
brane forms. After ten or twelve days, or even earlier, the thicker 
membrane begins to turn violet and a white precipitate falls in the 
still turbid liquid, in which are violet and white flecks. 
Milk. 
The casein is precipitated as a coagulum, and slowly dissolved. 
The liquid is alkaline. Later on a violet membrane forms above. 
Glucose. 
No fermentation, and no perceptible change at all beyond 
a very faint turbidity during the first few days. 
Air require- 
ments. 
Aerobic. 
