(b) Animals harmful to crops and gardens.
(c) Animals harmful to fruit and forest trees.
(d) Animals destructive to stored food or clothing.
(e) Animals indirectly or directly responsible for disease.
Laboratory Suggestions
Inasmuch as this work is planned for the winter months the laboratory side must be largely museum and reference work. It is to be expected that the teacher will wish to refer to much of this work at the time work is done on a given group. But it is pedagogically desirable that the work as planned should be varied. Interest is thus held. Outlines prepared by the teacher to be filled in by the student are desirable because they lead the pupil to individual selection of what seems to him as important material. Opportunity should be given for laboratory exercises based on original sources. The pupils should be made to use reports of the U. S. Department of Agriculture, the Biological Survey, various States Reports, and others.
Special home laboratory reports may be well made at this time, for example: determination at a local fish market of the fish that are cheap and fresh at a given time. Have the students give reasons for this. Study conditions in the meat market in a similar manner. Other local food conditions may also be studied first hand.
Indirect Use as Food.—Just as plants form the food of animals, so some animals are food for others. Man may make use of such food directly or indirectly. Many mollusks, as the barnacle and mussel, are eaten by fishes. Other fish live upon tiny organisms, water fleas and other small crustaceans. These in turn feed upon still smaller animals, and we may go back and back until finally we come to the Protozoa and one-celled water plants as an ultimate source of food.
