Berlin Medical Society, whose President, Prof. Virchow, explained that
it was thought advisable Dr. Koch should, in the first instance, give a
demonstration of his work before a smaller body than the whole society, so
that the proceedings might be fully reported in the medical press. He
mentioned that Herr Director Lucanus and President Sydow had expressed
their regret at being unable to be present, as well as many others,
including Drs. Von Lauer, Von Frerichs, Mehlhausen, and Kersaudt. Before
the meeting Dr. Koch exhibited microscopical specimens and drawings of the
cholera bacillus, and demonstrated the method of its preparation and
cultivation. The preparations included specimens of choleraic dejections
dried on covering glasses, stained with fuchsin or methyl-blue, and
examined with oil immersion, one-twelfth, and Abbe's condenser; also
sections of intestine preserved in absolute alcohol, and stained with
methyl-blue. There were also cultures in gelatin, etc.

[Footnote 1: A detailed report is published in the _Berliner Klinische
Wochenschrift_ Aug. 4.]

Dr. Koch commenced by remarking that what was required for the prevention
of cholera was a scientific basis. Many and diverse views as to its mode
of diffusion and infection prevailed, but they furnished no safe ground
for prophylaxis. On the one hand, it was held that cholera is a specific
disease originating in India; on the other, that it may arise
spontaneously in any country, and own no specific cause. One view regards
the infection to be conveyed only by the patient and his surroundings; and
the other that it is spread by merchandise, by healthy individuals, and by
atmospheric currents. There is a like discrepancy in the views on the
possibility of its diffusion by drinking water, on the influence of
conditions of soil, on the question whether the dejecta contain the poison
or not, and on the duration of the incubation period. No progress was
possible in combating the disease until these root questions of the
etiology of cholera are decided.

Hitherto the advances in knowledge upon the etiology of other infective
diseases have done little toward the etiology of cholera. These advances
have been made within the last ten years, during which time no
opportunity--at least not in Europe--has occurred to pursue researches;
and in India, where there is abundant material for such research, no one
has undertaken the task. The opportunity given by the outbreak of cho