Ward. — Some Thames Bacteria. 307 
as granular discs with a colourless margin and deeper centre, 
others are distinctly zoned, pink, and considerable variation 
in the depth of colour occurs, from pale-brick red to lavender- 
tinted rose-pink. 
Gelatine streak at 20°. In twenty-four hours the growth 
begins as a dry, pale lavender, tinted rosy streak, much the 
colour of almond petals. In a fortnight it has a curious 
appearance of striping, like fresh-cut muscle under a lens. 
The colour gets more like sealing-wax at the thickened 
base. The transversely striped appearance — due to ridges — 
seems a constant character. In the course of a month or 
more it slowly liquefies, and in six weeks seven-eighths of the 
gelatine is quite liquid. 
Stab-cultures at 12-15° show small dots in the puncture- 
line in five days, and a protuberant dry pink button above. 
The colour deepens to plum-pink as the button widens, and 
in eighteen days no trace of liquefaction occurs. 
At 20 0 the growth is similar (Fig. 4), but traces of sinking 
are found in five weeks ; in six to seven weeks the gelatine 
is liquefied half-way down, and even more. 
It requires three months or more to complete the lique- 
faction to the bottom. 
Agar. In forty-eight hours at 25 0 a dryish rosy streak 
of isolated and conjoining raised dots. In three weeks 
confluent to a shining, pasty, rose-pink, broad streak, with 
thicker axis, and flattened, radiately striated mesenteric and 
indented margins (Fig. 5). Consistence pasty. The hue is 
a lavender-tinted rosy pink, much like almond petals. 
After being in culture some time on Agar at 25°, numerous 
minute dot colonies are formed, hardly showing trace of pink 
in six days : faint pinkish deposit. The growth at 35° is 
still more faint, minute pink dots appearing in ten days. 
Potato. At 20-22° forms a pink, rather moist, spreading 
layer in three days, which in five days becomes almost 
vermilion, thin, and spread all over. The colour is very 
peculiar; perhaps carmine is the nearest hue (Fig. 6). The 
growth on alkaline potato is extremely slow, or even nil. 
