176 The American Naturalist. [February, 
Os O, + organi¢ substance = Os O, + oxidized organic substance. 
Os O, + 2H,0, = Os O, + 2H,0. . 
That is, in bleaching a tissue, the Os O, is converted into Os O, and 
water is formed, with which the tissue is already saturated. 
To restore 100 cc. of a 1% solution of osmium tetroxide requires 
from 10 to 20 drops of fresh peroxide of hydrogen, and clearing goes 
on better in full sunlight. To bleach tissue with peroxide requires 
about the same amount in 100 ce. of water, and the bleaching takes 
place better in the sunlight also. The amount needed cannot be stated 
with any more precision because the peroxide loses its strength some- 
what with age. The peroxide made by the Oakland Chemical Co., 54 
South Avenue, New York, is more stable and keeps better than many 
of the preparations in the market.—C. L. BRISTOL. 
PROCEEDINGS OF SCIENTIFIC SOCIETIES. 
The Geological Society of America.—The Fifth Annual 
Meeting was held at Ottawa, Canada, on December 28, 1892, and fol- 
lowing days. The following papers were read: Notes on the Early 
Palæozoic Sponges, Sir J. William Dawson, Montreal, Can.; Noteson 
the Devonian Formation of Manitoba and the N. W. Territories, J.F. 
Whiteaves, Ottawa, Ont. The object of this paper was to show the 
relationship of Devonian formation of Manitoba and the N. W. Ter- 
ritories with that of Northern Europe. In Manitoba the Stringoceph- 
alus zone is remarkably well developed and holds a rich fauna, whereas 
in the Mackenzie River district, most of the fossils so far collected 
seem to be from the Cuboides zone. On the Coals and Petroleums of ‘a 
the Crows’s Nest. Pass, Rocky Mountains, A. R. C. Selwyn, Ottawa, 
Ont.; On the Geology of Natural Gas and Petroleum in Ontario, H. 
P. Brumell, Ottawa, Ont. A brief résumé of work done in gas and 
oil explorations in Ontario, and dealing with the geological evidence 5 
adduced from record of wells sunk. Including also a short account of 
the geology of Southwestern Ontario. Some Features of the Phos 
phate Bearing Rocks of Ottawa County, P. Q., Elfrie Drew Ingall, : 
Assoc. Royal School of Mines, Eng. (Introduced by J. B. Tyrrell.) 
This was a preliminary paper, based upon field observations, discussing 
_ the phenomena exhibited by the Apatite deposits and their associated — 
rocks in their bearing upon the question of the probable mode of for 
mation of these deposits. Some Maryland Granites and Their Origm, 
Charles Rollin Keyes, Des Moines, Ia. A brief sketch of the granite 
