GLANDS. at 
b. Cells in situ: ciliary movement, 
Snip of a small piece of the epithelium from a freshly killed 
Frog, either from the tongue or from the roof of the mouth near 
the eyeball: mount in normal salt solution, and add a small drop 
of gamboge water to render the movements more clearly visible : 
examine with high power ; note -— 
i. The currents due to the ciliary motion. 
ii, The movements of the individual cilia: best seen 
when the specimen is beginning to die, and the 
movements to slacken in speed. 
IV. Stratified epithelium: cells arranged in several layers. 
Take prepared section of esophagus of rabbit, or of conjunctiva 
of rabbit or pig, which has been hardened in chromic acid, stained, 
and cleared in creosote and turpentine. Mount in balsam, examine 
with high power, and note :— 
i. The stratification of the epithelium. 
ii, The transition from the deeper spherical or colum- 
nar cells to the superficial squamous cells. 
B. Glands. 
A gland consists essentially of a layer of epithelial cells 
secreting some special] fluid, The epithelial surface may be 
flat, but is more usually folded, often in a very complicated 
manner, in order to increase the extent of the secreting surface. 
a, Simple Glands. In simple glands the epithelial surface 
is increased by simple pit-like depressions, whose mouths 
serve to discharge the secretion on the free surface, 
Take prepared section of large intestine of rabbit which has 
been hardened in chromic acid, stained, and cleared in creosote 
and turpentine. Mount in balsam, and examine first with low 
power, then with high. Note :-— 
i, The shape of the glands: simple tubular depressions 
of the surface. 
ii, The characters of the glandular epithelium lining 
the pits: a single layer of short columnar granu- 
lar cells. 
