Page 15 - ANIMAL MICROLOGY PRACTICAL EXERCISES IN ZOOLOGICAL MICRO-TECHNIQUE FOURTH REVISED EDITION BY MICHAEL F. GUYER

IMPORTANT GENERAL RULES
1. Keep everything clean!
2. Have a definite place in your desk for each piece of apparatus
and arrange reagents in order on top of it.
3. Use cards for keeping records of materials. Each card should
have a number corresponding to that of each special object or piece of
tissue, and should show the name of the preparation, date, reagents
used, time left in each reagent-in short, all data concerning the ma-
nipulation of the material.
4. Jot down in a blank calendar the various things to be done at
future dates, such as changing of reagent on tissues, etc., and then go
over this memorandum carefully each day when you first come into the
laboratory.
5. Use only clean vessels in preparing reagents, and clean up all
glassware while it is yet moist.
6. Reserve and mark a separate pipette for each of the chief re-
agents (absolute alcohol, oils, acids, etc.).
7. In making up solutions, I gram of a salt in 100 c.c. of liquid is
reckoned ordinarily as a l per cent solution, 3 grams as a 3 per cent so-
lution, ete. But if solutions are to be of 10 per cent strength or over, it
is better to weigh out the dry material to the desired percentage and
then add enough of the liquid to make the whole weigh 100 grams. For
example, to make a225 per cent aqueous solution of caustic potash, add
25 grams of caustic potash to 75 e.c. of water. A saturated solution
contains all of a given substance that the liquid will take up. When a
solution is called for without specifying the solvent, an aqueous solu-
tion is meant.
8. In weighing salts always first put paper in the scale pans to pro-
tect them.
9. In making solutions or mixtures in which only a small amount
of one reagent is used, after mixing, pour back some of the mixture into
the small vessel and rinse it thoroughly in order to get all of the origi-
nal contents out.
10. When pouring liquids from bottles keep the label of the bottle
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