But perhaps the most distinctively biological feature of the family is the inheritance of traits from one generation to another. Formerly, this passing on of characteristics from parent to offspring was a complete mystery, but its modus operandi is now clearly understood, as is explained in another chapter. We wish, in concluding this section, merely to point out how directly and poignantly the new science of genetics (based upon scientific research in zoology and botany) bears upon human welfare through the family.

The child defective in body or in mind, the"black sheep" that is supposed to appear in the best of families, the youth who goes to war and returns fit for nothing but a psychopathic hospital - all such, in a vast majority of cases, fail to cope with difficulties relatively harmless to their fellows, or fail to succeed in favorable surroundings, for the simple reason that they began life under a fixed handicap. This handicap was not bestowed upon them because of exceptional ability and as a mark of honor (as in sports), but because their parents produced defective factors of inheritance which happened, by chance, to find expression in the unfortunates under consideration. This negation of human welfare is theoretically preventable, if persons who carry defective hereditary units relinquish the privilege of parenthood, and it can be minimized if the situation is fully recognized (as it is, for example, in certain schools and hospitals). To learn the facts and make sound scientific recommendations in this field is the task of eugenics. No one can say that this task is more than begun as yet; but already sterilization and segregation of defectives is a recognized social procedure within limited bounds, education is beginning to recognize inherent grades of ability, and students who get some knowledge of biology are aware of other desiderata in marriage than money and obvious personal qualities. Family counts, but in a new way.

V

We do not know that any animal other than man has an intellectual outlook or a personal philosophy of life, but we do know that an individual of the human species experiences his share of human welfare and contributes to that of others in a degree very largely determined by his mental attitude. What does zoology contribute to the formation of a good philosophy of life?

In the first place, zoological study, like that of any other science, fosters in the student a concern for facts and a tendency to regard facts objectively. This helps to counteract the common habit of cherishing ideas that are based upon imaginary wish-fulfillments rather than upon truth a habit which is an immemorial foe to human welfare. Some tinge of scientific detachment is surely essential to an adequate philosophy, if a reasonable contentment is to flow from it, for to view nature egocentrically is to court disappointment. Secondly, some definite knowledge of zoological and other scientific facts is a necessary part of the mental equipment of any one who cares to live com-prehendingly in the modern world. It is apparently an unfortunate combination of fragmentary or vestigial knowledge of scientific fact - with a lingering and often unconscious yearning for the mystical certainties of a bygone day - that makes so pitifully inadequate the philosophy of certain moderns who are good writers and thus reach a wide audience. In his recent book,"The Conquest of Happiness," Bertrand Russell has devastating things to say about these vocal exemplars of maladjustment. A sound, though not necessarily extensive, experience of scientific work, such as is afforded by a good college course or two, will help to insulate the intelligent young against this form of injury to human welfare, and, at the same time, it will equip them to live sympathetically and safely - to feel at home - in a civilization which is distinctively the product of science.

There is another, and perhaps an equally important, way in which zoology contributes to the formation of an intelligent mental outlook. Evolutionary philosophy was developed from a condition of vague speculation through the efforts of many scientists, but it remains the especial glory of biology. Darwin's work made the evolution theory a living reality, and it inspired other zoologists and botanists to labor at the elucidation of multitudinous details, with the result that any one who is to gain a genuine knowledge of the principle must study the biological sciences. With this background it is possible to view, comprehendingly, modern philosophy, sociology, religion, and other studies in which the idea of evolution is an essentially vitalizing element. In consequence of such a view, the mental horizon is tremendously enlarged, and an intellectual outlook is attained from which the shadows of superstition and irrational fear have departed. Nothing could contribute more directly to human welfare than a study which is capable of imparting this liberating philosophy.

And there still remain to be mentioned certain intellectual benefits afforded by the scientific study of animals which are of real value, though they may be thought lacking in high philosophic dignity. A first-hand acquaintance with earthworms, fruitflies, insects, and mice - gained in anatomical and genetic studies - removes forever the stupid attitudes of fear or disgust which ignorant people often take toward such creatures, and thus helps toward a rational appreciation of nature. More than this, when we have noted how a mere Protozoan, like Paramoecium, moves about in its miniature world in a way startlingly similar to our own movements of trial and error in exploring a dark room or in pursuing the scientific method; when we have observed identical modes of eye-defect inheritance in a fly and in ourselves; and when we have found the same bones, nerves, and muscles in an ape as exist in our own bodies, we come into permanent realization of our intimate relationship with the lower animals. General recognition of this relationship will lead naturally to public confidence in the practical value of animal experimentation and willing support of institutions where it is carried on, to the sure advancement of human welfare. Finally, it may be suggested that persons who have studied such natural processes as excretion and reproduction, in surveying the physiology of animals, are not likely to be unduly impressed with inane taboos handed on to them from an ignorant and squeamish past. This is a point of greater importance than it at first may seem, for the insistent inculcation of these taboos in early childhood is responsible not only for a foolishly artificial attitude in regard to matters of everyday physiology, but also for the building up in the growing individual of abnormal phobias and useless inhibitions that are often ruinous to welfare. Children who have parents with some biological training will be likely to escape this danger.

We hear, on all sides, that what the distraught inhabitants of our modern world most need is an adequate philosophy of life to rescue them from tumbling igno-miniously into a vaguely defined abyss that seems to be yawning before them. Some saviors of society propose a retreat to fixed religious standards, humanistic or orthodox; others believe that a new economic scheme is what we need; still others call for fundamental changes in human nature, such as the assumption of disinterestedness. And there are the frank pessimists, already noticed, who should be for jumping in at once and thus putting an end to it. All such prophets seem unworthy of serious consideration to those whose philosophy of life is fortified by science. In this section we have seen how zoological knowledge, in particular, can afford some elements useful in the formation of an intellectual outlook adapted to the environment in which we perforce must live; and we who believe that it is possible for life to be reasonably happy and comfortable will not be surprised, when scientific knowledge in general becomes the basis for social ethics, if the consequent advancement of human welfare goes far beyond the present expectations of a reasonably guarded optimism.