microtome-a Ranvier model) and held in sit by several
pieces of soft cork. It is then imbedded in a cast of paraffin,
olive oil, and tallow, which after it has become hard, is held
in position by a number of small curved rods attached to, and
projecting upwards from, the piston to the height of about
an inch. Before cutting, and as it proceeds, the cast is care-
fully removed from     around the specimen to the depth of
about half an inch (which is easily done by the use of a good-
sized carpenter's chisel), so that the knife never comes in
contact with the cast."
Cutting is done under alcohol, the entire microtome being
immersed in a copper basin. The sections are floated, with
the aid of a fine camel's-hair brush, on to sheets of glazed
writing paper. They are removed thereon successively into
at    staining, washing, and clearing fluids. After clearing, they
are brought on the paper on to a slide, and the paper is
gently pulled away from     them; they are then mounted in
chloroform- or benzol-balsam.
It should be noted that the membranes should not be
removed from the brain; they present no obstacle to cutting
if this is done with a slight sawing movement, or with a series
of short cuts, instead of one sweep of the knife. By this
shall  plan the sections are much more perfect and uniform         in
deptd  thickness, and the loss in a series of from      four to five
adb hundred to the inch through the entire cerebrum of man may
i lie  not amount to more than 2 or 3 per cent.
 sala.  565. Spinal Cord. Bichromate and Silver-nitrate Process
akhol  (Golgi's method1).-I take the following resume' of the method
clhq   from  the interesting paper of Golgi's pupil, Rezzonico, 1. c.,
lfass  "Sulla struttura delle fibre nervose del midollo spinale."
Is is    1. Take pieces of perfectly fresh spinal cord, and soak
as   them in a 2 per cent. solution of bichromate of potash, for a
period  of time varying     according  to temperature.     (In
I