USEFUL AND NOXIOUS ANIMALS 21 
crabs). Some are quite extensively used as fertilizers (horseshoe crabs). 
The mollusks, aside from importance to other animals, give us our pearls, 
pearl buttons, shell work of all kinds (31), fertilizers, important food, ink, 
cuttlebone, etc. (32). 
The insects are of such importance that nearly every state and 
civilized country maintains an expensive staff of trained men whose 
business it is to advise the public in regard to their treatment and to 
investigate the relations of insects to industry. Their ravages or fear 
of the same are the basis of some of the speculation which enriches some 
and pauperizes other speculators in the necessities of human life. Aside 
from this we have the numerous products from insects—tincture of 
cantharides, honey, wax, lac (33), carmine (34), and cochineal. Many 
are used as human food in the tropics (locusts, water-bugs, flies, larvae 
of the palm weevil, etc.). Some few, such as the scorpions, are poisonous. 
Many diseases are known to be carried from person to person by insects 
and arachnids (cholera, yellow fever, malaria, sleeping sickness, typhoid, 
typhus, bubonic plague, mountain fever, perhaps leprosy) as well as a 
_ great host of larger parasites. 
We turn now to the vertebrates, which are familiar and their uses 
quite well known. From this group we get our leather, furs, animal 
oils (snake oil, fish oil, turtle oil, lard, whale oil, skunk oil, woodchuck 
oil, neatsfoot oil), all of which have recognition in the markets and some 
of which have peculiar properties which adapt them to particular pur- 
poses (32). Glue, gelatin, bone meal, fertilizers, bone black, etc., are 
extensively used in industries; meats, dairy products, furs, leather, etc., 
are necessities. 
We must not, however, fail to call attention to animals as the basis 
for nearly all experimental study of life processes, of heredity, of behavior 
and psychology, of diseases and their cure and prevention. The public 
should disabuse itself of the idea that biological investigators are wasting 
their time on bugs, for lower animals are the only material upon which 
the problems of our race can be solved, and until we are prepared to sub- 
mit ourselves to be used in the solution of our own problems, biologists 
will be compelled to use lower animals as material. 
