PRACTICAL WORK


*Observations.*—1. Make some scrapings from the inside of the cheek with a
dull knife and mix these with a little water on a glass slide. Place a
cover-glass on the same and examine with a compound microscope. The large
pale cells that can be seen in this way are a variety of epithelial cells.

2. Mount in water on a glass slide some thin slices of cartilage and
examine first with a low and then with a high power of microscope.
(Suitable slices may be cut, with a sharp razor, from the cartilage found
at the end of the rib of a young animal.) Note the small groups of cells
surrounded by, and imbedded in, the intercellular material.

3. Mount and examine with the microscope thin slices of elder pith,
potato, and the stems of growing plants. Make drawings of the cells thus
observed.

4. Examine with the microscope a small piece of the freshly sloughed off
epidermis of a frog’s skin. Examine it first in its natural condition, and
then after soaking for an hour or two in a solution of carmine. Make
drawings.

5. Mount on a glass slide some of the scum found on stagnant water and
examine it with a compound microscope. Note the variety and relative size
of the different things moving about. The forms most frequently seen by
such an examination are one-celled plants. Many of these have the power of
motion.

6. Examine tissues of the body, such as nervous, muscular, and glandular