( 645 ) 
A new character which may rise in addition to the already existing 
ones, is the production of a large quantity of slime substance by excessive 
growth of the cell-wall, which slime may spread through the liquids, 
and makes the individuals of the colonies on agarplates cohere into 
one tough mass. From B. Kieliensis was even a variant obtained 
whose colonies appear on the agar plates as a very consistent, almost 
dry zoogloea, but the analogous variant did not till now arise from 
the common prodigiosus. The viscosus (6), derived from the latter, is 
an ordinary red slime bacterium. 
This red-coloured, tough-slimy form, which may be called B. pro¬ 
digiosus viscosus, is no doubt a plus-variant. Its production has been 
observed under the most different nutritive conditions, between the 
temperatures 10° (in a cellar) and 30° C., but always and exclusively 
in liquid media, never on a solid one. The latter circumstance is 
apparently the reason why the numerous experimenters, who have 
studied B. prodigiosus, have not seen this variant. It is true that 
Scheuerlen x ) observed that old prodigiosus-cuitures sometimes turn 
slimy, but he ascribed it to their becoming alkaline and overlooked 
that a new constant form was produced. 
The only distinct condition which seems different in the liquid 
cultures compared with the solid, is the access of oxygen. In the 
depth of the liquid this access must, of course, be very deficient for 
a long time, or even be entirely lacking, as the upper layers of the 
culture, which are rich in bacteria, take up all the oxygen. Conse¬ 
quently anaerobiose becomes possible in the depth, which is not the 
case in cultures lying free on a solid medium, and this partial 
anaerobiose is apparently the stimulus which induces the formation 
of the slime variant. That here a rather complex influence and not 
a direct action must be ascribed to the partial withdrawing of the 
oxygen, follows from the fact that the culture of B. prodigiosus at 
complete exclusion of air, as in a closed bottle, does not, even with 
repeated transports, give rise to the slimy variant. At temperatures 
of about 35° C. this variant is no more formed, although the growth 
of prodigiosus is then still very strong; at 37° the growth slackens 
or ceases entirely, according to the food. 
In the following liquid media the production of the slime variant 
has with certainty been observed, as well after repeated re-inoculations 
as after prolonged keeping of one and the same culture at 25° to 
30° C.: in broth, in broth with 1 pCt of glucose, in malt-wort, in 
tap-water with 5 pCt of pure gelatin and 0,02 pCt K 2 HP0 4 , and in 
1 ) Archiv. fur Hygiene. Bd. 26 p. i. 
43 s 
