Mar. 12, 1917 
Spore-Forming Bacteria of the Apiary 
409 
Sometimes the growth is yellow, brown, or pink, imparting the same 
coloration to the potato. A liberal amount of water must be present in 
the tube to secure the luxuriantly wrinkled and folded characteristic 
growth (PI. 94, A). 
Agar slope.—A luxuriant, gray, raised, glistening, moist growth 
spreads over the whole surface. Often the growth is more or less wrin¬ 
kled. Later the coloration is brown or yellow, with occasionally a slight 
coloration of the medium near the surface. 
Milk. —Most strains exhibit a firm coagulum within 24 hours, then the 
coagulum is gradually digested, the band of turbid whey gradually 
extending toward the bottom until the whole tube is a thick liquid. 
Often there are floating flakes or masses, and a viscid sediment. 
Azolitmin and litmus milk. —Usually a pink coagulum is formed 
within 24 hours; later this is digested so that a gradually extending zone 
of turbid wine-red liquid is left above; still later the whole tube becomes 
a thick brown liquid with floating flakes or masses and a viscid sediment. 
At times no firm coagulum is noted; but the first change observed is the 
deep wine-red turbid liquid, which later turns brown. The changes in 
litmus milk show greater variation than in plain milk. The turbid 
brown coloration may appear early without the previous turbid wine-red 
coloration, or the brown liquid may be streaked with red or violet, or the 
tube may be a turbid brown liquid at first and later assume the red or 
violet coloration as a whole or in streaks. 
Gelatin stab. —Growth is usually manifest within 24 hours. Lique¬ 
faction proceeds rather rapidly, and is infundibuliform, as a rule, but 
usually becomes stratiform later. The medium is turbid, with a luxu¬ 
riant membrane at the surface and growth extending up the side of the 
tube. Later the membrane sinks and the liquefied medium clears, form¬ 
ing a large amount of sediment, which is flaky or cotton-like in appearance. 
Five per cent glycerin gelatin stab. —Same as plain gelatin, ex¬ 
cept that the growth is slower and usually less luxuriant. 
Indol. —None observed in any of the strains. 
Nitrate.—R eduction to nitrite is positive, with a strong red colora¬ 
tion on adding Greiss’s reagent. 
description of a strain from sample 2329 
In general, the cultural features and the morphology of the strain 
from sample 2329 resemble those of B . vulgatus , especially in the wrin¬ 
kled and coiled growth on potato. On agar plates, however, this strain 
has never manifested the characteristic folding or mottling of B . vulgatus 
as seen under a power of 90 diameters, always presenting a nearly even 
homogeneous structure, with a strikingly clear-cut periphery, and usually 
as finely granular structure as in B. mesentericus. Moreover, there is not 
the same tendency to a spreading growth, the colonies usually being small 
and decidedly convex or pulvinate, and often on agar presenting a 
