Ward ’ — Some Thames Bacteria. 305 
the cells. Specimens in water sometimes seem to be dis- 
tinctly vacuolated, or even to have granules in them, and 
some of these characters at first led me to suspect its being 
an extremely minute yeast-form — for instance, the vacuola- 
tions, the paler halo, and the grouping — but I have been 
able by cultures to determine that this is not so : it is a true 
Schizomycete. The fact that it does not ferment glucose 
solutions is, so far as it goes, evidence against the yeast 
view ; but of course it is far from conclusive, since plenty 
of yeasts do not ferment sugars. In the absence of any 
proof of budding I considered this form as probably a Micros 
coccus, and the occurrence of diplococci and rows of nearly 
or quite equal-sized cocci point to the same conclusion. 
On cultivating it at 19-20° in broth-drops under the j^th 
immersion it proved to be a Sarcina - like Micrococcus 1 , which 
divides in all three directions, but the progeny frequently 
partially separate later on, and only remain united in 
zoogloea-masses, and so form irregular botryoidal groups 
of cocci each 1-2 n in diameter. The high refrangibility 
of the gelatinous zoogloea investment makes it impossible 
directly to see the actual act of division, but enough evidence 
was obtained (see Figs. 8 and jo) to determine the nature 
of the organism. 
After being sown about twenty-four hours, the cocci are 
found dividing very regularly in the Sarcina - form (Fig. 8), 
but in the course of another twenty-four hours the cocci 
partially separate as they rapidly divide, and, rounding off, 
remain agglomerated in the characteristic grape-like manner 
shown in Fig. 8 d and Fig. 9. As time goes on, the separa- 
tion is more and more complete, and isolated cocci and 
diplococci are common in the drop. 
The series figured in Fig. 8 ( a to d) will show this. At 
11.50 a.m. a group of three Sarcina - masses was isolated 
(< a ) and watched : at 2.30 p.m. the Sarcina - divisions had 
increased as seen in ( b ), though it was impossible to accurately 
1 The type of Group XVII in Proc. R. S., Vol. xli, p. 421. 
