PREFACE. wii 
introduced, in many cases in the form of notes of 
personal experience relating to the habits of ani- 
mals, etc., as the growth of coral, the nest-building 
fishes, luminous animals, animal electricians, hiber- 
nation, mimicry, protection and defense—all sub- 
jects that, if enlarged upon by the teacher, will in- 
sure permanent interest. The student: should be 
encouraged to become an investigator and col- 
lector, and available suggestions concerning the 
best methods of collecting and preserving speci- 
mens will be found after each branch. Object-study 
should be required, and dissections and drawings 
made, no matter how imperfect the one or crude 
the other. 
A distinctive feature of this work is the refer- 
ence to the economic value of animals. In the 
Smithsonian, American Museum of Natural His- 
tory, Central Park, and other large institutions, col- 
lections have been formed to illustrate this subject, 
that is regarded as an important feature of public 
education. One of the commonest questions heard 
in museums is, “ What is the animal good for?” and 
considering the vast interests the lower animals 
represent, and their relations to man’s commercial 
dealings, the subject should at least be presented to 
the student. This has been done as briefly as pos- 
sible, in the form of suggestions to the teacher, to 
be enlarged upon as occasion offers. 
Collateral and supplementary reading is often 
