il of the tadpole, so frequently fed on by dragon-fly
larvae and other aquatic enemies, has great capacity of regeneration.
The study of its re-formation has added to our knowledge of the
regeneration of animal tissue. The circulation of the blood, so readily
seen by the aid of the microscope in the web of the Frog's foot, is a
classic and painless classroom demonstration. Observations on the
response of Frog-muscle to stimuli led the great Italian physiologist
Galvani to the discovery of dynamical or current electricity, known to
us as galvanic or voltaic electricity.

[Illustration: THE MALE FROG. (See Blower.)]

Nests and Nest Building.

Whenever the spawning period occurs, ample warning will be given, as
the male Frogs will begin croaking for their mate, and will be seen
near the shore. Early in the spring is the breeding season, and the
Frogs will be seen in pairs, working in company, selecting nests, which
are in place where there is a vegetation to attach the spawn, near the
surface of the water, as the action of the sun has much to do with the
hatching of the spawn.

Impregnation takes place immediately after the spawn is deposited, as
with the spawn of fish. The spawn of frogs looks like a gelatin mass in
the shape of a bunch of grapes, and will be found attached to some
vegetation in the pond. This should be immediately taken out with a
large, long handle dipper and deposited in the hatching pond, as the
spawn will be destroyed by the frogs jumping into the pond and coming
in contact with it, for if the spawn is separated or broken up and
sinks to the bottom of the pond, where it cannot get the proper action
of the sun, many of the eggs will not hatch, but will be destroyed and
eaten. The nursery, or hatching pond, should be constructed in this
way: Make some skeleton frames that will set on the bottom of the pond,
and come within a few inches of the top of the water. Fasten the frames
down, either by weights or stakes driven in the ground. Take some fine
netting such as used on windows to keep out flies; cotton or flax
netting preferred to wire. Fasten this netting to the frame. Be sure
that the netting is always covered with water when spawn is on it. On
this netting, deposit the eggs or spawn taken from the breeding pond.
In this way it will be undisturbed, and the sun can do its part toward
the hatching of the eggs. This method will be found successful, and you
can watch the progress, and the i