Some Thames Bacteria. 
BY 
H. MARSHALL WARD, Sc.D„ F.R.S., 
Professor of Botany in the University of Cambridge. 
With Plates XX and XXI. 
I. A short colourless Bacterium, forming stearine-like 
colonies 1 : type of Bacterium ureae (Jaksch). (PI. XX.) 
HIS form is apparently not uncommon in the river; 
JL I have isolated it several times, but have only culti- 
vated it twice through all media. 
It occurs on the plates as cocci, about i /x diam., not motile, 
and grouped in pairs, or rows of four, or isolated or in heaps, 
and evidently developed from the breaking up of short rods 
2 x i j a found with it (Fig. i). On old agar-cultures the cocci 
alone are found ; but in actively-growing gelatine-cultures the 
rodlets prevail and can be seen to be breaking up to cocci in 
all stages. 
No spores have been found in any medium. The rodlets 
stain easily by ordinary methods — e.g. Loeffler’s methylene 
blue, carbol-fuchsin, &c. — but they are easily decolourized by 
Gram’s method. 
1 This is the type of Group I, referred to in Proc. R. S., Vol. 6 1, 1879, P* 4 x 7 > 
[Annals of Botany, Vol. XII, No. XLVII. September, 1898.] 
