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bacilli without spores, sown in broth and cultivated at a temperature of
35° to 37° C., produce spores ; they are, therefore, not rendered truly
asporagenous by cultivation at 42° to 43° C. At too low a temperature
the bacillus does not form spores, but it does not lose the power of doing
so when cultivated at a proper temperature; spore formation does not
take place below 15° C. In 1883 MM. Chamberland and Roux ob-
tained asporagenous bacteridia, by causing weak antiseptics to act upon
the cultures, using phenic acid and bichromate of potassium for the
purpose. In this manner the bacillus cultivated for eight days in a
culture medium to which a two-thousandth of bichromate of potash was
added, lost the faculty of producing spores, and remained aspora-
genous in successive cultivations; it killed guinea-pigs in three or four
days, and the cultures sown with the blood of the charbonous guinea-
pig remained asporagenous. Lehmann, in 1887, discovered another
method of producing asporagenous bacilli, which only formed false
spores, and which did not regain the power of forming spores after
having been passed through guinea-pigs and mice, and his method was
repeated cultivation on gelatine. Behring, in 1889, obtained similar
bacilli by cultivation on gelatine, to which rosalic acid or an antiseptic
had been added in a dose insufficient to kill the microbe. M. E. Roux
has pointed out a certain method, and one easy of application, of obtain-
ing cultures of asporagenous bacilli. The following is a résumé of
his method:—Take eleven test tubes and place in them ten cubic
centimetres of veal broth rendered slightly alkaline; leave one as a
control, and add to the others weak doses of phenic acid, such as 2 ten-
thousandths to one, 4 ten-thousandths to a second, and so on, in such a
manner that from the first to the tenth there is a progression of 2 ten-
thousandths per tube; sterilize the tubes at 115° C., after sealing those
containing the acid in order to avoid loss; then sow each of the tubes
with a drop of blood, and put them in an incubator at a temperature of
30° to 33° C. The bacilli develop, if anything, more slowly as the
dose of phenic acid has been larger. The culture is always less abundant
in phenicated broth than in the ordinary broth, and it generally occurs
in flocculi, which remain in the depth of the liquid, if the tubes are
not shaken; at other times the development occurs in the whole mass
of the liquid, and gives it a troubled appearance; it is more especially
in the tubes, which are richer in the antiseptic, that this appearance is
produced. We should, if possible, avoid the cultivation occurring at the
surface of the liquid and forming a crown to it, which adheres to the
side of the tube. The bacilli, which increase in this manner, freely
exposed to the air, outside the culture liquid, quickly form spores,
principally in those tubes poor in phenic acid. When, therefore, floc-
culi appear, we submerge them by agitating the tubes a little. The