26 © Tue Microscope. 
tured end of a cell, in the very act of passing out of it. These 
cells must be regarded as normal structures undergoing mucous 
metamorphosis. Hematoxylin stains the mucous contents of 
these cells a deep purple-blue. Small pieces of the mucous 
membrane may be placed for forty-eight hours in a one per cent. 
solution of osmic acid. Itis then thoroughly washed in water to 
remove the excess of the acid and the cells separated from each 
other as much as possible with needles. All parts of the cell 
now show to better advantage. Any fatty particles are colored 
black by the acid and the body of the whole cell is slightly 
stained as well. Cells prepared after this method can be per- 
manently preserved in glycerine. 
CILIATED EPITHELIUM. 
Ciliated epithelinm may be readily obtained by gently 
scraping the mucous membrane on the roof of a frog’s mouth. 
If a large amount be desired, the frog may be killed and this 
entire membrane dissected off. For ordinary purposes sufficient 
epithelium will be brought away with the mucus by scraping 
the membrane zn situ with the point of aclean scalpel. A drop 
of normal saline solution should be placed on the centre of a 
glass slide and on either side of it a hair, in order that the cover- 
glass may not press upon the cilia and thus check their vibra- 
tions. The adherent mucus is then transferred from the knife 
to the salt solution. The preparation should be covered and 
examined at once with a power of at least 450 diameters. The 
cilia will be seen in active motion, driving any particles that 
come near them in one direc- 
tion. If the cellsare isolated 
or if only a few are in a group, 
the cilia will act like little 
paddles, causing the cells to 
whirl around and move about 
over the field. If there are no 
f blood corpuscles or granules 
A, Ciliated cell. B, Columnar cell. C to be driven about, particles 
The columnar cell, B, changed into a gob- of carmine may be added 
let celland filled with mucin, (After Klein 
and Smith.) to the specimen. This is 
best done by mixing a little granule of carmine with water and 
