tadpole develops,
the dark colour absorbs the sunlight, and this causes growth. The jelly
holds the eggs up so that the sun can reach them and it also keeps them
from being swept away by the water. The tadpole is very small, and
external gills are needed to keep it in very close contact with the
water. The tail does not drop off, the substance in it is absorbed into
the body of the growing toad to serve as nutriment.

Since all the changes in the development of the toad from egg to adult
form take place in about one month, this comparatively rapid development
makes the life history of the toad particularly suitable for observation
work.

The development of the eggs of the frog or newt may be studied from
preparations made in precisely the same way as those for the study of
the development of the toad.

If observations on the developments of two forms are carried on at one
time, interesting comparisons can be made on such points as, shape and
size of the eggs, time required for development, shapes and colours of
the tadpoles, activity of the tadpoles, etc.

THE EARTHWORM

~Time.~--May or June, in connection with gardening, when the working of
the worms in the moist soil of the garden is quite noticeable.

Outdoor studies may be assigned, as:

Observe the loose soil at the entrance to the burrows. Insert a straw in
the burrow and, following it, dig downward with a garden trowel and
learn the nature of the earthworm's home.

Are earthworms ever found out of their burrows during the day? If so, on
what kind of days? Why do earthworms burrow deep in dry weather?

Earthworms can breathe only when the surfaces of their bodies are in
moist conditions.

Go out at night with a lantern to where earthworms are known to have
burrows, observe the worms stretched out with the rear ends of their
bodies attached to the burrows, and note how quickly they draw back when
they are touched. Do they draw back if the ground is jarred near them?
Do they draw back when the light falls upon them?

State the facts which are taught by the observations which were made on
the above topics.

CLASS-ROOM LESSON

Put two or three earthworms into a jar of rich, damp soil, on top of
which there is a layer of sand a quarter of an inch thick. Put bits of
cabbage, onion, grass, and other plants on the surface and cover the jar
with a glass slip or cardboard.

After a few days, examine the jar, noting the number of burrows, the
foods sele