686 
FACTS AND OBSERVATIONS. 
procured a tooth at the depth of thirty-one feet from the 
surface, resting in a bed of sand beneath a four-inch stratum 
of bluish clay and gravel. Above the last was thirty feet ten 
inches of yellowish clay reaching to the surface. Beneath 
the sand, containing the tooth, was a gravel bed five feet in 
thickness, consisting mostly of rounded pebbles resembling 
river gravel, generally hornstone, many partially, and* some 
firmly, adhering together. Other pebbles shown him from 
the same bed were of iron ore, coal and micaceous sandstone. 
He was farther informed that some remains of fluviatile shells 
were found. He sent the tooth to Professor Joseph Leidy of 
Philadelphia, who pronounced it to be the last upper molar 
of a horse, probably an extinct species. From a similar 
gravel bed on the banks of Marais des Cygnes, a fragment 
of a tusk w r as given him resembling very much that of a 
mammoth. Its whole length was said to be seven feet four 
inches. About ten miles above Papinville, the banks of 
Marais des Cygnes River appear to be of a similar formation 
to the well of Ohlinger, consisting of about twelve feet of 
brown sandy clay resting on ten feet of blue clay w ? ith many 
pebbles of worn gravel at the lower part. These gravel beds 
he considers as of more recent age than the drift, but older 
than the bluff or loess, and regards them as altered drift. 
They seem rather to abound on the Osage and its tributaries, 
and are often reached in digging wells . — The Popular Science 
Review . 
Are the Pus-corpuscles derived from the White 
Blood-cells ? — There is no question in microscopic anatomy 
which has attracted so much attention from physiologists as 
this during the past two or three years, and now it seems, 
according to the researches of M. Picot recently laid before 
the French Academy, June 20th, 1870, that the idea of 
Conheim that the pus-corpuscles are partly produced by the 
passage of the white blood-cells through the blood vessels is 
altogether a mistake, is a misinterpretation of the phenomena 
in point. M. Picot, whose memoir was presented by M. 
Robin, gave a tolerably long account of his observations on 
the circulation of frogs and mammals, and he declares most 
positively that the white blood-cells never pass through the 
vascular walls, and that the pus-cells are formed gradually, 
external to the capillaries. He explains the error of Conheim 
and others, by stating that they confounded several focal 
planes together, and he considers that he has demonstrated 
this in the following way. He counted the number of white 
blood-cells in the arrested blood in the capillaries, both before 
