The most recent accomplishment in endocrinology is the preparation by Swingle and Pfiffner of an active extract of the adrenal cortex, distinct and free from adrenalin. This extract will keep alive cats whose adrenal glands have been removed and which would die at once without the artificially injected hormone. At the Mayo Clinic this extract has been successfully used in advanced cases of Addison's disease, restoring patients from a state of complete collapse to activity and "the appearance of perfect health." Thus another fatal disease is brought under control, as was diabetes a few years ago.

What has been said about the new zoological technique applies also to cancer research. Abnormal growths can now be transplanted from one mouse to another and otherwise studied more closely than has been possible in the past. One striking discovery that has been made in this work shows that certain cancers and tumors, when transplanted, will grow only in animals that belong to certain hereditary strains. If the mouse has a different hereditary constitution, the transplanted tissue will simply disappear. It is easy to see that such facts have a direct bearing on the whole question of constitutional susceptibility to disease, as well as on the problem of the incidence of cancer; and with the advances which these studies are bound to make there is every reason to suppose that we shall soon be able to deal with pathological conditions that are incurable and fatal in our present state of knowledge. For this we shall have to thank not only medical and surgical science, but also the zoological research which is fundamental to the success of clinical practice.

III

We have agreed that wealth is the second factor in human welfare, not as measured in millions, perhaps, but at least as represented in sufficient property and income to maintain us in reasonable comfort and to provide us with the opportunities and things that seem reasonably desirable. Many animals are of interest to us from this point of view; they destroy things we want, or they furnish things we can use. Now, economic zoology is the study of such animals, and it is not purely a matter of economics proper, because the effort to foster beneficial species and to destroy those which are injurious involves researches essentially zoological. The habits, life histories, physiology, classification, and distribution of economically important species must be known before practical measures can be formulated.

All civilized governments recognize the value of economic zoology and maintain more or less elaborate departments for its pursuit. Politicians come and go, but the scientists (who often fall temporarily under their dubious direction) remain, slowly advancing their laboratory, museum, and field work and contributing, after their fashion, to whatever measure of prosperity the country may enjoy under varying administrations. It is well for the public to realize this essential continuity underlying political change, and it would be to the people's interest if they gave more generous support to the government scientists and less superficial attention to administrative job-holders. It will astonish any able and successful business man to learn of the miserable salaries and appropriations under which many scientific departments must labor. Unless some popular branch of science is concerned, such as radio, legislative neglect and parsimony seem to be the rule. This situation could be changed, if sufficient pressure were brought to bear by interested and informed citizens. If such pressure should bring about increased appropriations for scientific work, we could be sure, at least, that the money would not be wasted in graft and display. For scientists are interested in science, and they are always seeking to improve their equipment and extend their researches.

One of the most important of the scientific departments of the United States Government is the Bureau of Entomology, which is devoted to the study of beneficial and injurious insects. Its practical work was begun by C. V. Riley, who in 1870 evolved the idea of using paris green to poison the potato beetle. This was a great success and rescued a valuable crop which was threatened with permanent destruction, as the insect spread over the country from its original home in the Southwest. Since that time the insect work has grown until about a thousand entomologists are employed, and a very extensive field of knowledge and technique has developed. Here it is especially evident that purely scientific investigation affords the foundation for practical results, and so the Bureau of Entomology includes men who devote their time to classifying and naming mosquitoes, flies, beetles, and other insects, to working out details of behavior and anatomy, and to studying breeding habits and immature stages, as well as those who are actively concerned in observing and checking serious infestations, wherever such may occur.

The native species are not alone concerned in the billion dollars worth of damage done annually by injurious insects. Some years ago the European gypsy moth and browntail moth became established and made a good start toward destroying the trees of New England; and their ravages have been held in check only through the constant efforts of experts and the expenditure of more than eight million dollars. At the present time the European corn borer, the larva of another moth, threatens to become a serious pest, a pest which would probably destroy the corn crop almost entirely if allowed to spread and multiply without attention from the economic entomologists. It was introduced into Massachusetts, probably in broom corn, in 1917 or a little earlier, and has spread as far as New Hampshire, Ontario, and Ohio. Poisoning is of little use, as the caterpillar lives inside the stalks of corn, dahlia, and other plants; so the methods of control, as deduced from scientific studies of the insect, consist chiefly of destroying the plant remains in which the species hibernates, and in preventing its further spread. If you are stopped on the road by an officer with a flashlight, it may not be a case of misplaced prohibition zeal; quite likely you will be asked if you have any vegetables or cut flowers in the car. The purpose of the inspection is to determine whether or not you are unwittingly a party to the spread of the corn borer into some hitherto uninfested locality.