l, fine-pointed scissors;
3. a pair of mounted needles (these can be made by forcing ordinary
sewing needles into handles of pine or other soft wood); 4. a hand
lens; 5. drawing-paper and pencil, and a note book.

For the study of the lower plants, as well as the histology of the
higher ones, a compound microscope is indispensable. Instruments with
lenses magnifying from about 20 to 500 diameters can be had at a cost
varying from about $20 to $30, and are sufficient for any ordinary
investigations.

Objects to be studied with the compound microscope are usually
examined by transmitted light, and must be transparent enough to allow
the light to pass through. The objects are placed upon small glass
slips (slides), manufactured for the purpose, and covered with
extremely thin plates of glass, also specially made. If the body to be
examined is a large one, thin slices or sections must be made. This
for most purposes may be done with an ordinary razor. Most plant
tissues are best examined ordinarily in water, though of course
specimens so mounted cannot be preserved for any length of time.[1]

[1] For the mounting of permanent preparations, see Chapter XIX.

In addition to the implements used in studying the gross anatomy, the
following will be found useful in histological work: 1. a small
camel's-hair brush for picking up small sections and putting water in
the slides; 2. small forceps for handling delicate objects; 3.
blotting paper for removing superfluous water from the slides and
drawing fluids under the cover glass; 4. pieces of elder or sunflower
pith, for holding small objects while making sections.

In addition to these implements, a few reagents may be recommended for
the simpler histological work. The most important of these are
alcohol, glycerine, potash (a strong solution of potassium hydrate in
water), iodine (either a little of the commercial tincture of iodine
in water, or, better, a solution of iodine in iodide of potassium),
acetic acid, and some staining fluid. (An aqueous or alcoholic
solution of gentian violet or methyl violet is one of the best.)

A careful record should be kept by the student of all work done, both
by means of written notes and drawings. For most purposes pencil
drawings are most convenient, and these should be made with a
moderately soft pencil on unruled paper. If it is desired to make the
drawings with ink, a careful outline should first be made with a hard
pencil and this in