200 Ward . — Thames Bacteria , III. 
The first ‘ form ’ or ‘ variety ’ of this type which I have 
isolated has the following characters : — 
No. 103 : Proteus mirabilis (Hauser). 
This form is not common, but occurs in the summer. On 
the plates it consists of short rodlets 1*5 to 1-25 /x long by 1 /x 
broad, breaking down to cocci about 1 /x diameter (Fig. 4). 
It is quiescent, and no spores have been found. 
In broth, however, it forms rods 3-6 /x long by 1 jx broad, 
breaking to shorter rodlets or joined into short filaments 
10-12 /x long : all active, the filaments with gliding serpentine 
movements, the rodlets darting hither and thither. On potato 
the cocci are soon formed. 
On plates at 18-20° C., the colonies are visible in twenty- 
four hours as zoogloeas spreading into very characteristic 
white spider-like and moss-like forms (Fig. 1) ; and under 
the Jrd they are seen to consist of moniliform irregularly 
branched submerged zoogloeas, sending floating islands off 
on the surface, exactly as in No. 34 in principle, but more 
attenuated and divided (Figs. 2 and 3). To the unaided eye 
the figured colonies are quite white, or slightly yellowish in 
a few days : under the lens the zoogloeas are dull whitish 
ochre, and the floating islands transparent and difficult to see 
at first. As the culture ages, these islands become yellower 
and denser and are then easily seen. One curious feature is 
the rapid course of the growth : after the second day the 
colonies did not enlarge at all, apparently, but more careful 
examination showed that the tenuous films of floating islands 
were spreading over the surface. There was no sign of lique- 
faction in fourteen days. 
In other plates the first signs are visible in 12-20 hours 
under the § as isolated coils and filaments, tresses, & c., which 
imitate tendrils of varying degrees of fineness according to 
the number of filaments and the closeness of the coiling. 
These lie chiefly on the surface. The zoogloeas result from 
the same closely coiled up into skeins and balls. 
