SUPPURA TION.

195

small cocci, forming long chains—generally from six to
ten individuals, but sometimes reaching a hundred in

fig. 55.—Streptococcus erysipelatis, seen in a section through human skin;
x 500 (Frankel and Pfeiffer).
number. Occasionally the chains can be found collected
in tangled masses. They can be cultivated at the room-
temperature, but grow much better at 30-37° C. They
are not particularly sensitive to the absence of oxygen,
but develop a little more rapidly in its presence.
The erysipelas cocci, like the Streptococcus pyogenes,
are not motile, form no spores, and are destroyed by a
low degree of heat. They stain well with aqueous solu-
tions of anilin dyes and also by Gram's method.
The colonies upon gelatin and the development in
gelatin tubes, upon agar-agar, and upon blood-serum
are identical with the descriptions of the Streptococcus
pyogenes. No growth occurs on potato.
The growth in bouillon is generally luxuriant, and in
a short time causes the medium to be filled with chains
of the cocci. As the growth progresses these chains
gather in clusters and fall to the bottom as a whitish