INTRODUCTORY WORK q 
convenient sizes. A few small bottles with balsam-bottle 
stoppers for such stains as iodine, a cubic centimeter gradu- 
ate, some water-flasks, some squares of glass for covering 
jars, glass slides and cover-slips for mounts for the micro- 
scope, also a few pieces of glass tubing of different sizes, 
will be needed. 
(e) Preserving fluids——Alcohol grading from 85 to 95 
per cent may be obtained at drug-stores, and should be 
reduced to 70 per cent for preserving specimens. Forma- 
lin, a 40 per cent solution of formaldehyde, is cheap and 
very useful as a preservative. A 34 to 5 per cent solution 
of formalin is best. These preservatives should be kept 
ready for use at any time. 
(f) Microscopes—Small glasses magnifying 8 to 10 
diameters can be had at very slight expense. A convenient 
form is one mounted upon a tripod, and such a glass should 
be at the disposal of each student. Every laboratory should 
have at least one good compound microscope, and, if prac- 
ticable, one for each student. Two or three persons may 
work successfully with a single microscope, but if one only 
is supplied for all the students, it may be used in demon- 
stration work for the benefit of the entire class. With but 
one instrument for all, little individual microscope work 
can be done; but gross structures may be studied, and with 
class demonstrations under the microscope quite creditable 
work may be accomplished. 
The idea that botany can be studied with profit only 
by means of the microscope is erroneous, although its use 
greatly increases the interest and the value of the study. 
If funds are limited, it will be better to purchase one 
good compound microscope than two or three poor ones. 
Poor instruments soon get out of order and must be re- 
paired or replaced, while one good one should serve for 
many years. The stand of the instrument should be strong 
and sufficiently heavy to keep it from being easily over- 
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