INTRODUCTORY HISTOLOGICAL STUDY 
19 
Preliminary Practice in Focusing and Using the Microscope. 
Examine, for this purpose, one of your own eyebrow hairs or 
an eyelash, mounted in a drop of water placed in the middle of 
a slide. In order to enclose this drop between two parallel sur¬ 
faces, it should be covered with a clean cover-slip. This must be 
applied with care in order that air bubbles shall not be included, or 
the upper surface of the cover-slip itself flooded with the water. 
To obviate these difficulties hold the cleaned cover-slip by one 
edge by means of the forceps and, applying the opposite edge of 
the cover-slip to the slide at the edge of the drop which is to be 
covered, gradually lower the cover-slip upon the drop. Inci¬ 
dentally it is advisable to make one mount with air bubbles 
included and use these also as objects for study under the 
microscope. 
Study the hair, thus mounted, under low power for its general 
form and proportion, recording these by means of a carefully 
planned drawing of the whole hair. Then select some one region, 
the location of which should be indicated upon the drawing of 
the hair as a whole, for the study of the minute details under the 
high power. Note that owing to the thickness of the object, the 
details studied must be selected with great care by focusing upon 
some definitely determined plane or surface. Draw the details 
thus studied. 
For further practice a few fibers of cotton, linen, wool, and 
silk may be successively examined, mounted as above directed. 
Draw carefully each object examined with sufficient detail to 
distinguish them from each other and to enable you to recognize such 
objects if at any time they become accidentally included in your 
preparations of other material. 
A. FRESH MATERIAL, SHOWING CELLS IN A CONDI¬ 
TION AS NEARLY AS POSSIBLE TO THAT WHEN 
LIVING. 
Throughout the following study keep always in mind the fact 
that cells are three dimensional objects and that a correct idea of 
their forms cannot be gained from a single aspect. Look, there¬ 
fore, for cells in various positions. Try to turn cells from one 
position to another by gently pushing the cover-slip along while 
