In conducting our life, we must never let ourselves ignore the natural order of things. True, we still preserve the illusion of being privileged among living beings and of escaping the common law. The sense of being free gives us a deceptive confidence. We believe that our situation is vastly superior to that of plants, trees and animals. It is important for us to have a clear idea of our true place in nature.

The human body, as we have known since Aristotle, is an autonomous unit in which all the parts have mutual functional relations and exist to serve the whole. It is made up of tissues, blood and consciousness. These three elements are distinct, but inseparable from each other. They are equally inseparable, though distinct, from the physical, chemical and psychological milieu in which we are immersed. All the substances which make up blood and tissues come directly or indirectly from this environment through the medium of plants and animals. The greater part of our body is composed of the water of rain, springs and rivers. This interior water holds in solution definite proportions of minerals which originate in the earth. It constitutes the substratum of the cells and the blood. Like earth and sea water, it contains sodium, potassium, magnesium, calcium, iron, copper and a quantity of rarer elements such as manganese, zinc and arsenic which come to us from animal flesh, milk, cereals, vegetables, tubers and roots. Plants and animals also supply the nitrogenous matter; the fats, sugars, salts and vitamins we need to build up, maintain and restore our tissues. The chemical components of our bodies are identical with those which make up the sun, moon and stars. There is no difference between the oxygen in the atmosphere of Mars and the oxygen we breathe. The hydrogen contained in the molecule of the glycogene of liver and our muscles and the calcium of our bones are the same as the hydrogen and the calcium of the flames in the atmosphere of the sun filmed by Mac Math. The iron in the red globules of our blood is the same as that of the meteorites. The atoms of sodium which float like fine mist in interstellar space could be used just as well by our tissues as the salt in our food. In fact, all the chemical elements of which our bodies are made up come from the cosmos; from earth, air and water. Those elements behave in the same way whether inside the body or out. Claude Bernard taught us that the laws of physiology are fundamentally the same as those of mechanics, physics and chemistry. Things do not vary in their mode of being: the laws of capillary attraction, osmosis and hydrodynamics remain true in the heart of our tissues. It is possible however, on Donnan's hypothesis, that certain statistical laws cease to operate in certain cells so small that they contain only a few protein macro molecules.

Thus our body is a fragment of the cosmos, arranged in a very special way, but obeying the same laws as the rest of the world. It is made up of the same elements as its physical ambience. Moreover man is functionally related to his environment. Each is adjusted to the other in such a way that one could say the environment is the lock and man the key. The surface of the earth presents a set of physical and chemical conditions which are exceptional in the universe and eminently suited to our existence. Our planet retains about it an atmosphere dense enough for living creatures to breathe the oxygen they need even on high mountains. This same atmosphere protects plants and animals from cold and from the harmful rays of the sun. And the attraction the earth exercises on all bodies makes us adhere to its soil in the degree necessary to our mode of life.

On the surface of Jupiter we should be immobilized by our weight. On the moon we should be too light. As Henderson has shown, the cosmic milieu is adapted to life mainly on account of the peculiar properties of three elements: oxygen, hydrogen and carbon, which compose water and carbonic acid. Water and carbonic acid stabilize the temperature of the earth. Moreover water liquefies nearly all chemical elements. Once liquefied, these elements penetrate everywhere and serve as food for plants. Hydrogen, oxygen and carbonic acid are the most active of all elements. They create the greatest number of compounds and the most complex molecular structures. Thanks to water which brings them the majority of chemical elements in solution, plants and animals can prepare the complicated nutriment man needs. This environment conforms to life and vice versa. Life uses two processes in this conforming. The first consists in absorbing or assimilating the environment. Thus the organism absorbs oxygen from the air and assimilates nourishing substances. The second consists in reacting against the environment and in adjusting itself to it. The adjustment comes about through an effort of the great adaptive systems.1 The repetition of this effort increases the power of these systems; i.e. the vessels, nerve centers, muscles, glands, heart and all the organs. This is why the individual needs to be in constant struggle with his environment if he is to develop to his highest capacity. Hard conditions of life are indispensable to bringing out the best in human personality.

Learned men often made the strange mistake of observing natural phenomena as if they themselves stood outside nature. The fact is that they are part of a material system composed of observer and observed.

True, our mind is not confined in the four dimensions of space and time.2 Though we are immersed in the cosmos, we feel we have the power to liberate ourselves from it. In some way we do not yet understand, the mind can escape from the physical continuum. Nevertheless, it remains inseparable from the body and thus from the physical world to which it is subject. The blood plasma has only to be deprived of certain chemical substances for the noblest aspirations of the soul to vanish. When, for example, the thyroid gland stops secreting thyroxin into the blood vessels, intelligence, sense of good and evil, sense of beauty and religious feeling disappear. Increase or diminution of calcium both upset mental balance. Chronic alcoholism disintegrates the personality. If, as Madame Collum did, one completely cuts out manganese from the diet of a female rat, the rat loses its maternal instinct. On the other hand, if one administers prolactine (a particular extract of the pituitary gland) to virgin rats, the animals adopt young rats, build nests for them and cherish them with the utmost care. If no young rats are available, they will devote their mother-love to newly-hatched pigeons. Our feelings are definitely and deeply influenced by certain illnesses. A mild dose of sleeping sickness may result in a total change of personality. When the spirochaeta pallida, the parasite of syphilis, begins to invade the brain, it sometimes illuminates the intelligence with flashes of genius. The state of the mind is conditioned by that of the body.

1 Man the Unknown. 2 Ibid.

On the surface of the earth we are beings analogous to other beings; nearer, however, to plants and animals than to rocks and rivers. We are closely related to the higher mammals, particularly gibbons and chimpanzees, but our minds are vastly superior to theirs. Thanks to our intelligence, we are free to act as we choose. It is this sense of freedom which gives us the illusion of being independent of nature. Though it is true that we are free, we are, all the same, subject to the natural order of things. If we wish, we can ignore nature's laws. We can get out of a boat in order to walk on the water, we can jump from the top of the Empire State Building, we can take hashish and live in a marvelous dream world or give ourselves up to the corruption of modern civilization. But we can never break the bonds which bind us to the earth from which we spring. The will of man will always be impotent to alter the structure of the universe. Since we are part of nature, we must conform to her laws, as Epictetus taught We must be that which it is in our very essence to be.