1 06 Journal of A gricultural Research voi. viii. No. 3 
from Schuster also showed characters on agar slants which differentiated 
it from all of the other cultures, including the one just mentioned. The 
growth while filiform at first was more abundant, and later it spread out 
in a broad band one-third to one-half the width of the slant. It was 
thicker, somewhat convex and yellowish, and not opalescent. It very 
soon imparted a very distinct yellowish-brown color to the substratum. 
Agar stabs. —The first six organisms mentioned in the above section 
produced the same appearance on agar stabs. The growth was fairly 
uniform but slightly best at the top, although perhaps not more than 
would result from the heavier inoculation of the upper layers of the 
medium. The entire surface was covered in from a few days to about 
a week, depending upon the amount of free moisture present. The 
line of puncture was filiform to very slightly papillate. 
The two organisms carried under the name “B. phytophthorus ” grew 
decidedly best at the top, and the one from Schuster caused a distinct 
browning of the medium, beginning at the surface and diffusing down¬ 
ward. 
Cookkd potato cylinders. —The character of the growth on the 
cooked potato has been a prominent one among those given by different 
authors as differentiating from the others in the group the organisms 
which they have described, consequently considerable attention was 
given to this topic. 
For the work potatoes were chosen which were either freshly dug or 
had been in storage only a few weeks. In all cases the tests were made 
on slanted cylinders of sterilized potato in test tubes containing a small 
amount of distilled water. The tubes were inoculated as soon as sterility 
was proven, by making a single stroke with a straight needle along the 
center of the slant. 
Inoculations made to tubes of this kind gave practically identical 
growth characters for B. atrosepticus , B. solanisaprus , B. melanogenes, 
IIIA, SE, and IIP, which are as follows: 
At 20° C. little or no growth apparent in 24 hours; needle growth 
plainly evident in 48 hours, and if the slant is rather moist, the growth 
may have spread out by this time to cover a considerable portion of the 
lower part; in three days, growth moderate to abundant, filiform to 
spreading, depending upon the amount of water in the substratum; one 
week, growth abundant and spreading, usually covering the entire surface 
of the slant. Elevation first convex, then slightly raised to flat; luster 
glistening; topography smooth to slightly rugose; color yellowish white, 
resembling pus in appearance, later dirty white; odor not apparent at 
first, but later slight odor of decayed potatoes; consistency butyrous, 
with a slight tendency to viscidity in the case of B . solanisaprus and B . 
melanogenes. Medium at first slightly grayed, and at the end of a week 
plainly grayed. 
