Ward . — Thames Bacteria , III . 237 
carbo-hydrates. As we shall see, also, several other varieties 
exist which behave similarly. 
No. 31 : Yellow Proteus Type. Figs. 46-48. 
This form was often met with in the Thames. It occurs on 
the plates as rods 2-4 /x x 0-5 or o-6 /x, or as coiled filaments 
of rodlets 2-3 /x long and about 0*7 /x (in water) thick. Other 
measurements give 2-6 x 0*5 to o*6 /x. 
Plates at 12-15 0 give white circles with star-like central 
portion, opening out to arborescent or sheaf-like branched 
forms, with ‘ wandering islets ’ and rapidly liquefying. 
At 1 8-21° C., the colonies appear on the fourth or fifth day 
as translucent, circular, contoured, colourless or bluish fronds 
with a yellowish central boss ; the edges extremely tenuous, 
and the central parts varying to spidery and contoured figures. 
In a week the colour becomes pale-ochre, and liquefaction 
begins; the colonies 10 mm. or so in diameter forming floc- 
culent mottled and flame-like masses in the liquefied depres- 
sion. All the stages from the contoured type (Fig. 47 a) to 
the forms with mosaic-mottled clouds are to be traced (Figs. 
46, 47, and 48). 
Plate-cultures after passage through broth show in twenty- 
four hours as spider-like colonies. In forty-eight hours all 
stages of the type are seen : the submerged yellowish ovals 
and the spidery-like zoogloeas with tails. They emerge as 
thin contoured plates, colourless, and with wandering ring- 
lets (see Figs. 47 b and c). On the fourth day they open out 
as pale ochre sieves, like No. 23, and liquefy (Fig. 48). 
Stab-cultures at 12-15°. A sieve-like flecked yellowish- 
white membrane grows above, and floats in a week on the 
softening gelatine as a clouded patch : yellowish dots in the 
tunnel. About the ninth day the dirty-white to yellow- 
ochre cloudy growth is sinking, and in a fortnight it 
resembles No. 23. In two months half the tube is liquefied, 
rather turbid, and has a floating flecked veil. 
At 1 8-21°, in forty-eight hours a yellowish- white small 
R 
