The great question today is how to improve both the mental and organic state of civilized humanity; that is to say, how to work for the development of beings superior to any who have hitherto inhabited the earth. This enterprise is necessary because our intelligence has not increased at the same rate as the complexity of the problems to be solved. Thus we are on the downward path. Modern society has been preoccupied with material values. It has neglected fundamental human problems which are both material and spiritual. Not only has it not brought us happiness but it has shown itself incapable of preventing our deterioration. The conquest of health is not enough. We must also bring about in every individual the finest development of his hereditary power and of his personality, for the quality of life is more important than life itself.

We must therefore find the means of artificially producing in every man activities which, while increasing his capacity to adapt himself to the social and cosmic world, will also stimulate his mental development These activities manifest themselves especially in moral sense, judgment, robustness of spirit and resistance to folly. They spring from intelligence and intuition. But, to be really useful, character and intelligence demand as substratum a balanced nervous system, organic strength and natural immunity to disease.

During growth, body and mind possess great plasticity. This plasticity permits them to obey the influence of all the factors in their environment. Innumerable observations have shown that climate, profession, diet, athletics, certain intellectual and moral disciplines, etc., make a deep imprint on the personality. Even variations of one single condition of development, such as diet, are enough to produce great changes in animals. In the course of experiments made at the Rockefeller Institute in New York the size of pure-bred mice was increased or reduced at will. In one group, the average weight of the young at one month old went down to just over 6 grams while, in another group, it reached over 11 grams. The length of life proved to be equally modifiable. In one large group, given an excellent diet, 9 per cent of the mice lived more than twenty months. In another group, given the same food two days a week, the number of mice who lived longer than twenty months rose to 60 per cent. The mortality of the young before weaning was also influenced by the diet of the mothers and went down from 52 per cent to 19 per cent. Changes in diet modified the natural resistance to pneumonia. As many as 52 per cent of the mice which made up one of the groups died of pneumonia. An improvement in the regime lowered the mortality to 32 per cent, another modification to 14 per cent. The addition of a certain chemical substance completely suppressed the disease. But, in this last group, as many as 83 per cent of the mice died of tumor of the liver, at a later age. More subtle characteristics appeared. In one group which for several years received a diet excellent in quality but insufficient in quantity, the size became smaller while the intelligence markedly increased. On the contrary, both intelligence and size diminished in a group which was given sea water with its food.

These observations show the great fluidity possessed by the living organism. It is, therefore, not unreasonable to try to obtain, by a wise use of physical, chemical and physiological factors, a spiritual improvement of the human being.

The formation of body and mind depends on the chemical, physical and psychological conditions of the environment and on physiological habits. The effects of these conditions and these habits on the whole make-up of the individual ought to be exactly studied with reference to all activities of body and mind.

A. Effects of Chemical Factors - Thanks to the science of nutrition, we know how to feed children so that they will grow tall and strong and their death rate will be extremely low. But this science has not taught us how to give them a robust nervous system, a balanced disposition, courage, moral sense and intelligence, nor how to protect them against mental degeneration. This problem concerns the future of millions of children. It is urgent, therefore, to begin to study it. It can be approached by three convergent methods.

The first will consist in repeating the experiments made on mice and rats on a very large group of extremely intelligent and pure-bred dogs. With the help of psychological and chemical tests, it would be possible to measure the effect of different diets and of certain chemical substances on the mental and organic state of these animals.

As dogs become adult in one year, many results would be rapidly obtained. But others, such as the effects of feeding on degenerative diseases and on longevity, would appear much more slowly. One would have to perform these experiments over a period of something like twenty-five years.

The second method would include the examination, from the point of view of alimentary regimes, of human groups which have not yet been standardized and also of groups of men or animals who have been naturally isolated in particular conditions of existence. Some retrospective studies would probably be possible. Furthermore, one would submit to a critical examination the regimes approved by the medical body and those alimentary superstitions which have important results on the psychological and organic stage of large groups of individuals.

The third method would be experimental. It would consist in applying the data we already possesss, and those which will be shortly acquired, to groups of children in Europe, America and Africa. This experiment would last over a hundred years.

B. Effects of Physical Factors. - Civilization tends to suppress natural climate. By protecting men against inclemencies of weather and by submitting them to new physical conditions in houses, offices and factories, it has created artificial climates. It is necessary, therefore, to study the influence of heat, damp, uniformity of temperature, wind, dust, fields of electricity, gases, noise, etc., on the organic, nervous and psychological state. This problem will be approached by the same methods as the preceding one. The results obtained will be valuable indications for the construction of houses and towns and for general habits of life.