will be very slight as compared with
the horizontal.

When the object is raised a little above the brass plate, a keen edged
razor, thoroughly wet, is pushed over the hole, cutting the object. This
gives the section a smooth surface, and even with the plate; now push the
plane forward one-eighth to one-quarter of an inch, and cut again; this
will give a thin section of the object. The thickness of the section
depends, of course, on the distance the wedge is pushed.

With a little practice, much better sections can be cut by the hand than
by any machine; this does not apply of course to large sections. A razor
of good steel, with a blade thin and hard, are the most essential points
in an instrument for hand cutting. For ordinary purposes it is not
necessary to have the blade ground flat on one side, although many prefer
it. The knife should always be thoroughly wet, in order that the cut
tissue may float over its surface. Water, alcohol or salt and water may
be used for this purpose.

[Illustration: FIG. 1.]

_To out a section by hand_, hold the object between the thumb and first
two fingers of the left hand, supporting the back of the knife by the
forefinger. The knife is to be held firmly in the right hand, and in
cutting should never be pushed, but drawn from heel to point obliquely
through the tissue. The section should be removed from the knife by a
camel's hair brush.

When the object is too small to hold, it is usually _embedded_ in some
convenient substance. A carrot is sometimes very useful for this purpose.
A hole rather smaller than the object is cut out of the middle. Put
whatever is to be cut into this, and cut a thin section of the whole. The
carrot does not cling to either the knife or the section, and the knife
is wetted at every slice by it.

Paraffin is the agent usually employed for embedding purposes. Melt it,
and add a little lard to soften it; the addition of a little clove oil
renders it less adhesive.

Melt the paraffin at as low a temperature as possible, and pour it into a
paper cone. Dip the object into this and remove immediately; as soon as
the layer of paraffin surrounding it becomes hardened, replace it in the
paraffin; this prevents overheating the tissues.

Where the tissues are too soft to be cut, they may be soaked in a
solution of gum arabic and dried; in this condition they can be readily
cut, after which the gum can be dissolved off. This is an extremely
useful method for