INTRODUCTORY HISTOLOGICAL STUDY 
27 
Then place the slide in the jar of xylol to remove the alcohol 
and render the stained sections transparent. There should be 
no milkiness in slide or surrounding fluid at this stage. 
When the sections are perfectly transparent (i.e., cleared) 
remove the slide from the xylol, drain and wipe off the excess of 
xylol, place a drop of Canada balsam on the sections and cover 
carefully with a perfectly clean cover-slip. Label the slide with 
the name of the structure sectioned and with your own name 
together with other data such as the direction of the section, thick¬ 
ness of section, stain, etc. Leave in a horizontal position until 
the balsam is hard, taking care never to pile slides upon each other. 
C. PERMANENT MOUNTS (DEM. SL. COLL. 1 ) SHOWING 
EXAMPLES OF CELLS FROM DIFFERENT TISSUES. 
Study each preparation with care, noting in each case the 
source of the material, and the method of preparation which has 
been employed. Make drawings to show your conception of each 
type of cell studied with the arrangement of cells when this is shown 
by the preparation . 
Cells of Epithelial Tissue, Showing the Characteristic Arrange¬ 
ment of Cells to Form a Continuous Layer. — (E.g., a surface mount 
of the outer layer of epidermis of a salamander or frog obtained 
from a recent moult.) 
Cells of Skeletal Tissue, howing the Characteristic Wide 
Separation of the Cells by Intercellular Material.— (E.g., a section 
of 10-15 mm. pig embryo showing embryonal skeletal tissue with 
stellate cells.) 
Cells of Muscle Tissue, Showing the Characteristic Elon¬ 
gated Form of Contractile Cells.- — (.Eg., a teased preparation of 
smooth muscle tissue from the muscle coat of the intestine of a 
cat.) 
Cells of Nerve Tissue, Showing the Characteristic Branched 
Form of Cells with Wide Separation of the Cell Bodies.— (E.g., 
1 The term Demonstration Slide Collection (Dem. SI. Coll.) is used to designate 
such slides as may most advisably be arranged by the teacher for the students to 
examine, rather than given out to the students. It is recommended that such a slide 
be accompanied always by an adequate explanation or diagram, or by a suitable 
reference to some text-book of histology. 
