132 The American Naturalist. [February, 
liquefies allowing the colony to settle to the bottom of a pit. 
The funnel of liquefaction extends rapidly over large areas of 
the plate. Owing to this rapid liquefaction successful gelatin 
plates can be made only by very thin sowings. In most cases, 
the whole plate was soon liquefied at 25° C., if somewhat 
abundant sowings were made. In stab cultures, dot-formed 
colonies first develop along the track of the needle and finally 
fuse so that the stab appears as a thread. The liquefaction 
begins at the mouth of the canal and proceeds very energetic- 
ally so that ordinarily in 48 hours at 25° C., the whole gelatin 
has become fluid. Streak cultures on nutrient gelatin are very 
characteristic. Within 12 hours the track of the needle ap- 
pears as a raised dirty white line. The line spreads rapidly 
and widely to each side, forming a surface not unlike an elon- 
gated, irregularly margined leaf. Scarcely has this leaf formed 
when the gelatin begins to liquefy. Such streak cultures can 
be carried on only at room temperatures and with inoculations 
from cultures that have been grown on gelatin repeatedly; 
otherwise, the gelatin is liquefied too quickly. 
(3) Agar.—On plate cultures of nutrient glycerin agar the 
organism forms small, dirty-white, slimy drops. When exam- 
ined with a hand lens these appear to be round, have a sharp 
contour, and show in the interior a brownish center. In stab 
cultures the track of the needle appears as a thread, and the 
organism spreads from the mouth of the canal toward the peri- 
phery as a delicate layer (Auflagerung). 
(4) Potato, ete—On potato it forms a dirty-white, slimy layer, | 
which at first gives an acid reaction, and then becomes strongly 
‘alkaline. The decomposition proceeds rapidly through the 
whole slice of potato, 2 to 3 days, at 25° C., being sufficient to 
involve the whole thickness. During this decay there is a 
copious evolution of gas from the interior, bubbles as big as & 
pin head bursting through the slimy covering and leaving ™ 
it little funnel shaped openings. 
(5) Animal Fluids—Judging from statements cited under — 
Pathogenesis C., probably several were tried but there is no 
specific mention of anything but milk. In this fluid the 
organism caused the separation of the casein but no other 
