od ZOOLOGICAL EXERCISES. 
c. Mix a little indigo with salt water. Take a drop up 
in a fine brush. Place the edge of a piece of 
blotting-paper against the lower edge of the cover- 
glass, and apply the brush containing indigo to the: 
upper edge. A current will at once be set up under 
the cover-glass which will carry in the indigo. Re- 
move the brush and blotting paper. Watch the 
infusoria, and notice the currents caused by their 
cilia. Careful observation will show that many of 
the infusoria swallow the indigo, and by this means. 
their alimentary system can be distinguished. 
EXERCISE VIL. 
a. Take a very small fragment of the flesh of cooked meat 
and tease it out ona slide in a drop of water with two 
mounted needles. Get it as fine as possible. Put on 
a cover-glass, and examine first with the inch, then 
with the quarter objective. It is striped muscular 
tissue, made up of bundles of transversely striated 
muscular fibres. Each fibre can be broken up into 
jrbrillee. 
EXERCISE VIII. 
a. Collect out of a rock pool at low tide several bunches of 
fine, much branched sea-weed, taking care to shake 
them as little as possible in the pool. Wash them 
for examination with a high power, and placed in the centre of the field. 
Much time is often lost in attempting to find an object with a high power 
which might be found at once with a low power, and then, if placed in 
ae centre of the field, will be found in the field when the high power 15 
put on, 
