abiogenesis; as well as works
on the bacteria of air and water, the significance of the bright sulphur
granules in sulphur bacteria, and of the iron oxide deposited in the
walls of _Crenothrix_. His discoveries in these and in other departments
all stand forth as mementoes of his acute observation and reasoning
powers, and the thoughtful (in every sense of the word) consideration of
the work of others, and suggestive ideas attached to his principal
papers, bear the same characteristics. If we overcome the always
difficult task of bridging in imagination the interval between our
present platform of knowledge and that on which bacteriologists stood
in, say, 1870, we shall not undervalue the important contributions of
Cohn to the overthrow of the then formidable bugbear known as the
doctrine of "spontaneous generation," a dogma of despair calculated to
impede progress as much in its day as that of "vitalism" did in other
periods. Cohn had also clear perceptions of the important bearings of
Mycology and Bacteriology in infective diseases, as shown by his studies
in insect-killing fungi, microscopic analysis of water, &c. He was a
foreign member of the Royal Society and of the Linnean Society, and
received the gold medal of the latter in 1895. He died at Breslau on the
25th of June 1898.

Lists of his papers will be found in the _Catalogue of Scientific
Papers of the Royal Society_, and in _Ber. d. d. bot. Gesellsch._,
1899, vol. xvii. p. (196). The latter also contains (p. (172)) a full
memoir by F. Rosen. (H. M. W.)

COHN, GUSTAV (1840- ), German economist, was born on the 12th of
December 1840 at Marienwerder, in West Prussia. He was educated at
Berlin and Jena universities. In 1869 he obtained a post at the
polytechnic in Riga, and in 1875 was elected a professor at the
polytechnic at Zurich. In 1873 he went to England for a period of study,
and as a result published his _Untersuchungen uber die englische
Eisenbahnpolitik_ (Leipzig, 1874-1875). In 1884 he was appointed
professor of political science at Gottingen. Cohn's best-known works are
_System der Nationalokonomie_ (Stuttgart, 1885); _Finanzwissenschaft_
(1889); _Nationalokonomische Studien_ (1886), and _Zur Geschichte und
Politik des Verkehrswesens_ (1900).

COHOES, a city of Albany county, New York, U.S.A., about 9 m. N. of
Albany, at the confluence of the Mohawk and Hudson rivers. Pop. (1890)
22,509; (1900) 23,910, of whom 7303 were f