Mar. i2, 1917 
407 
Spore-Forming Bacteria of the Apiary 
yellow, brown, or a dull slate. To secure the characteristic netlike growth, 
there must be an abundance of water in the butt of the tube (PI. 94, B). 
Agar slope.—A gray, raised, glistening growth spreads rapidly over 
the surface of the medium. Later the growth turns brown or yellow, 
and a gray ground-glass cuplike membrane often forms at the butt over 
the water of condensation. 
Milk. —A coagulum is formed usually after about the third day. Fol¬ 
lowing this, there is partial digestion of the coagulum, which is never 
complete, as in B. vulgaius. The coagulum may soften or undergo 
change in consistency and rise in the tube later, so that a very thick, 
slimy liquid results. 
Azolitmin and litmus milk.— Sometimes a change may be noticed in 
24 hours, the color turning slightly pink; later changes are manifest 
either by the tube turning a deep wine-red color or forming a soft, 
curdy, pink coagulum. As in plain milk, the curd is not entirely digested, 
a residue always remaining at the lower part of the tube, or the whole 
tube is a brown or black, thick, slimy liquid. 
Gelatin stab— Liquefaction is not evident usually until the second 
or third day; then a slow, stratiform liquefaction proceeds, usually com¬ 
plete after a month or six weeks. A gray membrane is formed at the 
surface; and in the liquefied medium there is a turbidity, and floating 
flakes are present. Later the medium clears, forming a large amount of 
sediment at the bottom of the tube. 
Five per cent glycerin gelatin stab. —Growth is sometimes very 
slight without liquefaction. Liquefaction, when it takes place, is much 
slower than in plain gelatin, and is incomplete, but there are the same 
growth characteristics as to membrane, turbidity, and sediment as in 
plain gelatin. * 
Indol. —None observed. 
Nitrate reduction to nitrite. —Usually negative. Sometimes a 
positive reaction may be observed in a strain which usually gives a 
negative reaction. 
Bacillus vulgatus (Flugge), Migula, Lehmann and Neumann (8) 
Syn. Bacillus mesentericus vulgatus Flugge; Bacillus A. White (16), Common name, potato bacillus 
Occurrence. —Same as that of Bacillus mesentericus. 
Gelatin colonies. —Colonies at first are barely visible to the naked 
eye. Under a magnification of 90 diameters deep colonies are found to 
be more or less circular, irregular, finely granular, and often quite dense, 
with mosslike outgrowths, or with long raylike processes. Surface 
colonies present at first a finely granular appearance, and later usually 
become folded and mottled; later a membrane, more or less cotton-like, 
floats on the liquefied area. 
. Agar colonies. —If only a few colonies are on a plate, they spread 
rapidly to almost any size, are not circular, and do not manifest a clear- 
