Social contact with the past. From the very beginning we are immersed in a world which is not of our own making. It is a world of persons and things, existing in certain relations to each other, and arranged in a great diversity of patterns. It takes but little study and reflection to convince one that all of these relations and patterns have had a history, that few of them are of recent origin, and that all of them could not possibly have originated at the same time and under the same set of conditions. Into this world which treasures and enshrines elements from so many different pasts we are expected to fit ourselves, and in doing so we are brought into varying degrees of intimacy with an immense social heritage.

The range and diversity of this social heritage it would be difficult to overestimate. Nor would it be easy to exaggerate the subtlety with which it insinuates itself into the innermost recesses of our life. We live and move and have our being within its confines. It lies around us at all times ready to be woven into our lives, ready to be gradually and painlessly (for the most part) assimilated until we have become thoroughly shaped to its likeness. If we at times feel moved to resign and disown it all, we know not whither to turn, for in denying it we should be forced to renounce ourselves. To grow up in and absorb a way of life is to be created in the image of that way of life. Minor changes and innovations of no great significance are of course occurring all the time in every group, but these are of little effect in altering the pressures under which men live. Only to the extraordinarily gifted, or to the extraordinarily lucky, is it given to break even a few of the bonds which bind them to the past the gifted man may now and then by sheer power carve out some new thing, the lucky man may now and then by fool's right stumble upon that which was hid.

Interdependence of the biological and social factors.

Heredity works from within outwards, and has therefore often been regarded as furnishing the raw materials of growth and development; whereas the social heritage works upon the organism from the outside, somewhat like a molding force. Both factors are absolutely indispensable in the formation of developed human beings, as is strikingly shown by the pitiful stories of the scattered instances of presumably normally endowed individuals who for one reason or another have grown up since infancy in isolation from their fellows. These persons have impressed those who observed them as being more like animals or idiots than like normal human beings. They have com

monly proved almost uneducable, and most of them have pined away rather rapidly under the strange pressures of civilized life."

Heredity may be conceived of as furnishing the limits within. which individual development, as elicited by the social and physical environment, takes place. No study yet made, however, has disclosed the exact limit of biological capacity of any individual with respect to any single trait. As a matter of fact, no satisfactory enumeration of distinct biological traits seems possible at the present time so far at least as the human being is concerned. There is an increasing body of evidence tending to show that the germ plasm does not contain single simple determiners which press relentlessly on to the development of specific bodily traits, but rather that these traits are caused by the co-working of comparatively large numbers of determiners under the precise environmental conditions present at the time when the traits in question begin to appear. Under different conditions the same set of biological determiners will produce a different individual. It is clearly unwise, therefore, to regard heredity as an entity or force when it is taken in abstraction from a supporting and eliciting environment.

The influence of the group upon the germ plasm.

In the preceding section it has been suggested that the environment is effective in helping to determine the direction of development. Do environmental influences also act so as to alter the germ plasm itself? That clearly is a very different question, since modern biology stands firmly on the principle that the germ plasm remains unchanged no matter what qualities make their appearance in the individual during the course of development. A group of individuals, from the biological point of view, might rather be considered as an aggregate of germ plasms carried in separate persons than as a collection of persons. The persons may be what they are largely because of environmental influences; but what of the germinal materials they carry within them? Are these too subject to environmental determination?

It is not necessary to assume that the social environment has a direct influence on the germ plasm in order to answer this question in the affirmative. The group is clearly able to affect the germ plasm indirectly, by processes of selection. Any social activity which picks its participants will turn the trick, provided the selected group also shows a higher or a lower birth rate than the average for that time and place. For, as we have seen, the presence of bodily traits in the members of a group is an index to the presence of germinal determiners in the germ plasm of

the members of that group; and a higher or lower birth rate for that group will therefore act, if the environmental situation remains constant, so as to perpetuate or to destroy the group, with its germinal determiners.

Many social arrangements have had precisely this effect. Perhaps the most obvious instances are to be found where persons belonging to certain restricted groups are either discouraged or prohibited from having children. Members of religious orders in many societies are in this position, and members of the teaching profession also suffer this disability in our own culture. The same result of altering the germ plasm of a group is achieved whenever a selected group of persons is subjected to an unusually high death rate during the years when its members would still be biologically fertile. This happens in our society in the case of those who go to war, as likewise in the case of those who live in unfavorable social environments or engage in dangerous occupations.

The above cases, of course, by no means exhaust the instances where the social environment will be found indirectly determining the biological constitution of the group. The selection of bodily traits among the young when at all severe inevitably means the selection of germ plasm, since the traits which make their appearance in the body, and are selected, also go to make up the determiners in the germ plasm (together, of course, with those traits which according to the laws of heredity fail to appear in the body). And the group is continually engaged in this process of selection, according to canons and standards which differ widely from place to place. There are always rules and understandings determining how groups and individuals shall come to meet each other; who shall marry whom, and under what conditions; how many children there shall be, and at what times in the parents' life-cycles; which children shall be favored, and in what manners; etc.

Who shall be born and who shall live and come to maturity, and under what conditions, are thus not pure matters of biology. They also depend on the prevailing social arrangements, and on the ideas entertained by the group at any given time. The infant is not only born helpless and immature into a social group. In a very real sense he is born of the group. He is its child quite as truly as he is the child of his parents.

Conscious efforts to improve the biological stock.

We are beginning to see that the chief biological difference between the germ plasm and the body is that the former in

cludes within itself the possibility of a considerable number of traits not actually displayed in the body. Thus with every new generation there is a new deal, and it is really in part up to us whether we wish to play the new hand in the same old way. Neither the individual nor the group, however, have done much up to date towards the conscious and deliberate selection of the coming generation. It is to be doubted whether we possess sufficient detailed information at the present time to carry out any extensive program of eugenics, or improvement in our biological stock. In breeding out traits which we regarded as undesirable, as, for example, certain neurotic tendencies, we might find ourselves committed to the extinction of other associated qualities of great social importance, as perhaps some kinds of artistic ability. Certainly no very positive measures seem at present feasible. At the same time, some students of the subject have suggested that the stock might be improved by discouraging childbearing among: (1) the feeble-minded and others of less intelligence; (2) the victims of hereditarily transmissible diseases (including mental and venereal diseases and alcoholism); (3) those subject to severe congenital defects of vision, hearing, and speech. Any such program would have to be administered with greater care than it would be likely to receive, however, lest it result in more harm than good to the race.

The human organism.

We may now turn to a brief consideration of the human body as a biological organism. Like most of the animals, man is built on a generally symmetrical plan, a fact of very great influence in determining how he acts. He differs structurally from all other animals in his upright posture, in the possession of extremely flexible hands (his first and most important tools), of a delicate apparatus for the production of sounds, and of a still more finely equilibrated brain and nervous system. His behavior shows a greater plasticity, as is evidenced by his much longer (proportionate) period of infancy and immaturity, and by a broader span of attention and interest. He is unique in the degree to which he can respond to signs-witness his many different systems of communication-and as an inveterate user and maker of tools. He is by no means the only animal who has created a society, but no other animal has lived under so many different social forms as he.

The human organism has its beginning when, through the union of the sexes, a fertilized germ cell begins that long and complex process of cell division which finally results in the fin

ished human product. This process is probably not completed until some time after birth. One of its most important features is the progressive specialization of the resultant cells, both as to structure and function, until eventually the entire galaxy of muscle, nerve, gland, bone, blood, germ, connective and other cells has put in its appearance, and the different parts of the body have assumed their appropriate general relations to each other. If the human organism were tremendously enlarged, we could see each of these cells separately functioning, with about the same degree of independence of each other that individuals show when they are engaged in a variety of more or less similar tasks requiring different degrees of cooperation.

These cells are arranged at birth in a number of partly coordinated systems, each partially independent and performing its own peculiar functions, while at the same time it remains in more or less close association with the remaining systems, and is continually acting in concert with them, in any one of a large variety of ways. The organism is therefore a rather loose aggregate of interacting parts or systems, among which may be named the respiratory, circulatory, digestive and excretory, glandular (including sexual), and nervous (or neuro-muscular) systems. That these systems to a considerable degree depend on each other is shown by the fact that they seldom function separately and alone. At the same time complete coordination is a never realized ideal, for although many coordinations not present at birth are established as a result of development, the process is never carried very far in proportion to the possibilities, and disturbances of existing coordinations are also continually taking place. Among the many coordinations that are achieved are all of the manifold instances of learning; while among the numerous disturbances of existing coordinations are such things as nervous indigestion, where the ability of the stomach and intestines to digest food and excrete waste is affected by changes in the nervous system brought about by psychological maladjustments.

Organic needs.

A need may be naturalistically defined as anything which is necessary to the functioning of a biological system, either when it is working in comparative isolation or in intimate association with other systems. The various parts of the organism are capable of working without trouble and friction only when these needs are satisfied within certain rather fixed limits. Thus the respiratory system needs air, but, more than this, it needs air of a