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spores which were maintained in position by a mucous uniting substance,
but soon separated, becoming free. He observed that at 35° C. the
bacilli rapidly developed and presented spores at the end of 24 hours,
whilst at 30° C. they did not form them for three hours, at 18° to 20° C.
at the end of two or three days. Below 12° and above 45° C. the
bacilli did not develop. He recognized that the development of the
bacilli required the presence of air, and that if cultivated in a medium
poor in oxygen, they became muddy, broke up, and were destroyed.

Pasteur in 1877 devoted himself to the study of contagious disease;
he completed the demonstration of the parasitic nature of charbon; he
demonstrated, by employing the method of successive cultures inaugur-
ated by him, that the bacillus was the morbific agent of charbon, and
that, if the virus resisted the action of compressed oxygen, this was due to
the great tenacity of the spores which it contained, and which, contrary
to what is the case with the rods, are not influenced by it.

Koch had observed that the microbe of charbon might reproduce
itself by scission or by the endogenous method. During the life of a
sick animal, the batonnet multiplies by scission, elongates, is compressed,
bends in one or several places, separates into several segments or baton-
nets, which in their turn comport themselves in a similar manner after
death. The batonnets cease to multiply by scission, oxygen being want-
ing and septic bacteria get the upper hand. The bacilli, however, under
certain conditions, produce spores before their destruction, which, once
formed, may preserve and perpetuate the virulence for a long time.

Pasteur, as we have said, submitted charbonous virus to successive
cultures outside the organism, and repeated the experiment a great
number of times, and, at last, isolated the bacillus from all the ele-
ments which accompanied it in the drop of blood employed to sow the
first culture; these elements did not multiply and finally disappeared;
the bacillus alone multiplied and became purer in each successive cultiva-
tion; it was obtained pure under the form of filaments; and by inoculat-
ing the liquid which contained it, charbon was induced with multipli-
cation of the bacillus. If the culture liquid or charbonous blood
was filtered through porcelain, it was deprived of the bacilli and
ceased to be virulent. The method of successive cultures, repeated
a number of times, permitted us to get rid of all the elements which
accompanied the bacillus, such as red and white globules, granular
matter which were introduced in sowing the first culture, and trans-
mitted in less and less numbers to some of the subsequent ones. The
cause of charbon then is the bacillus and no other element, since the
bacillus alone was preserved in the whole of the cultures, and neither
a dissolved substance nor any poison whatever produced by it and