Ward. — Some Thames Bacteria. 289 
measured 300x180/;, which, calculated as before, gives us 
540,000 cocci or 270,000 rodlets. 
Numerous other cultures only confirmed these results, and 
neither filaments nor spores could be obtained in any gelatine 
medium ; while the minuteness of the organism rendered 
futile all my attempts to directly observe its growth in 
liquid media. 
During active growth the rodlets 2x1/; prevail, but as the 
colony ages these all break into cocci. 
Stab-cultures at 12-15 0 show up in three days, but the 
development is slow. Yellowish-white dots appear in the 
tunnel, and a thin, dull, ground-glass-like frond above. This 
is hard and tough, like stearine, and difficult to scrape off. 
In fourteen days the surface is nearly covered, the frond with 
beautifully indented margins and radiate structure. No 
further growth in the tunnel. The matt appearance is due 
to a rough shagreen-like surface (Fig. 4). 
At 22 0 the development is equally good on acid or alkaline 
gelatine, and on the third day the characteristic matt frond 
appears above. The dots in the tunnel coalesce a little, 
indicating feeble growth. No trace of liquefaction. In old 
cultures the gelatine is slightly brownish-tawny above, and 
the colony has a faint greenish yellow tinge. The stab is 
sword-shaped. No trace of liquefaction even after three 
months’ culture : the yellowish white, thin, waxy, shagreened 
growth just covers the top of the gelatine, and has delicate 
fimbriate margins. Colonies submerged in the gelatine 
exhibit no growth. 
Streak-culture at 20° spreads fairly quickly, as a white, 
thin, matt film, like stearine or ground-glass, in forty-eight 
hours. In seven days nearly the whole surface is covered 
with a beautifully frondescent very thin film, spreading from 
the thicker streak, flush with the surface, greyish-white like 
ground-glass (Fig. 5). No sign of liquefaction even after two 
months. Edges very thin and fern-like. 
On agar at 30-35° a faint streak and one or two thin spots 
appeared in two days : these hardly increased in eight days. 
