MEDICINE AND GROWTH1

DOUBTLESS friends have congratulated you on the fact that you were through." In one sense-a strictly academic sense that is true, else you would not be here, subject to this ordeal. But perhaps there is another way of looking at the situation. The Greek philosopher, Pyrrho, contended that against every statement the contradictory may be advanced with equal reason, and following this estimable skeptic, I feel justified in the assertion that, as a matter of fact, you are not "through," but rather are just commencing doctor of medicine, if one may give the word commence its older meaning.

You have qualified for a degree-a degree which entitles you to membership in a learned profession-that, like the church and the law, has the distinguishing responsibility of dealing with matters of life and death.

A profession makes heavier claims on its representatives than does a trade or an art, for in the nature of the case it demands continued progress, and it is part of the unwritten law that those who enjoy the prestige which such a position brings, should leave their profession better than they found it.

To do this implies progress-progress by growth, and it is the idea of growth that I wish to use as a guiding thread for the conduct of this talk. It is my purpose then to say a word concerning growth as it affects that very important person, the patient; then to speak of growth as it touches the body of medical knowledge; and finally to consider growth as it affects the physician in his riper years.

To follow an old time form let me announce 1 Address to the graduates of the Medical Department of New York University. Delivered at the special commencement exercises, held at University Heights, New York, on Saturday, March 1,

1919.

my first thesis, namely: that a patient is always changing, growing.

Johannis Bernoulli, a member of the most remarkable family of mathematicians of which we have a record, published in 1699 a thesis in which he maintained the continual change of substance of the body.

His argument drew the theological lightning of his day, and he forebore to push his studies further, but his ideas were passed along, and I know that in my youth no self-respecting popular physiology failed to repeat the statement that the human body underwent a complete change of substance once in seven years.

We look at matters somewhat differently today but it is not without interest to record that this idea of change started under such eminent patronage. The modifications due to growth are another matter, yet the idea of growth, despite the universality of the phenomenon, has been only gradually assimilated and put to use.

In earlier times growth was but little considered. We need not go back very far in medical history to find that the typical patient was the person already grown. The patient was thus standardized.

The young were dealt with by midwives and grandmothers, and the aged took care of one another.

Speaking in the broadest way the physician's business was to care for that mythical person, the average man, to whom the recorded facts of anatomy and physiology all applied; for the phases of growth were not then regarded in these disciplines, and medicine shared with art and education a curious blindness to developmental changes. Great advances have occurred. We now have those clinicians who give special care to children, to adolescents or to the aged.

The relations of age to the incidence of disease, as in the children's diseases, in typhoid or in cancer, have directed attention to progressive alterations within the individual, a series of changes which are quite aside from the marks of maturity or the signs of old age. Thus men of a given race pass through a

series of well recognized phases and, as in a set of dissolving views, infancy merges into childhood and childhood is transformed to youth, and so within the span of life we have revealed the seven ages of man, so quaintly sketched by Shakespeare.

Familiar as these phases are it has taken no small labor to bring them into the field of practise and to have them recognized as of clinical importance. There is the same difficulty here that appears in carrying over to our laboratory work the ideas of variability and of graded relationship which were developed by Darwin and those who followed in his steps.

We know that individuals differ in their form and anatomy, but we wish they didn't; it would be so much easier if they were all just alike.

We know, too, that what is true of structure is also true with regard to the functions of the body. Here the facts are harder to appraise, and there is a still stronger tendency to dodge them. But this avails us nothing. The facts will find us out-and moreover they are unpleasantly immortal.

The idea which I wish to drive home is this: During the span of life the body shows changes more or less like those shown by a battered ship or neglected automobile, but behind these lies a set of changes which no dead structure or machine exhibits, a progressive chemical alteration of the body linked with age, probably affecting all its parts, and constituting the series of modifications characteristic for the individuals of any species, as these pass from birth to senile death.

The mechanism which prepares our food; that which distributes the food-bearing blood; the nervous system which controls our behavior; the muscles which do the work, and the internal secretions from the ductless glands and other sources which serve to tune or tone our organs, all these undergo with age changes not only in themselves but in their relations to one another.

On the balance of these component parts depends that somewhat subtle character called

temperament, which though elusive, has a real existence and an importance hard to overestimate. Temperament is the expression of these relations and one of the nice problems the clinician has to face.

Under certain circumstances it makes a difference whether one has light hair or dark, not because these characters are themselves important, but because they are indicative of subtle dissimilarities in the chemistry of different individuals, dissimilarities which are of far-reaching importance for the individual as a whole.

Recently it has become possible to do our laboratory work with animals the ages of which are known. Working thus we find at every turn differences, distinct and definite, dependent on the age, differences which should be studied, for without shadow of doubt they will be found in man when search for them is made.

I make no question that much of what I have just said to you has a familiar sound, but the time is coming, I feel sure, when the significance of age will be appreciated in many fields where now it is but little noted, as for example in the blood, and I have spoken thus to specially direct your thought to these matters.

Thus far the individual who is growing normally and who represents the usual case has been considered. In passing, however, it may be worth while to turn for a moment to the individual subjected to starvation. The terrible years through which the world has just passed have brought starvation vividly before us. We know that in starvation growth is modified and may apparently be stopped.

As in so many other instances our knowledge of the changes thus induced is still fragmentary and incomplete. In the first place we must distinguish between the starvation which follows when the quantity of an adequate diet is made unduly small, and the case in which the diet is unbalanced and defective in itself, and therefore only slightly modified by quantitative variation. It is the former case to which I would draw attention here.

If we may trust the tests with animals, two systems tend strongly to resist mere quantitative underfeeding—the skeleton and the nervous system. Growth in them is greatly retarded to be sure by underfeeding, but they may still grow, while the body as a whole is held at a constant weight or is even losing.

The practical question before us however is not so much the immediate effects of starvation, as the response which such an animal will make when it is brought back to a full and normal food supply.

The nervous system is best known to me and I think we may say with regard to this system that a return to the normal diet is followed by nearly, if not quite, complete recovery. This is a cheering and hopeful result and yet, as always, a word of caution is in place. Starvation, as followed in the laboratory, can be studied free from the complicating conditions of the exhausting systemic diseases, so often associated with starvation in human communities, and what is true for the simple conditions of the laboratory may not be true for those which are more complex.

Nevertheless in these days, when underfeeding is much in evidence, it is of interest to note that one form of it at least does not cause permanent damage to the great master system of the body.

The life histories of many students and productive scholars support this conclusion, for biographies show only too frequently, periods of starvation in the lives of those who, then and later, were distinguished for intellectual activity.

Thus far I have been speaking of growth as it modifies the patient, when that longsuffering person is looked at as a biological problem.

Now let me pass to the second topic and ask you to consider the growth of medical knowledge.

The mass of knowledge in any subject may be likened to a sphere which is rolled on from generation to generation, always growing by additions on the surface.

All of us, as scholars or investigators, are entrusted with its preservation and its in