The greatest engineering feat of which we know anything is the building of a complex animal organism from a microscopic ovum. Think, for instance, of the marvels of the human body with its pulleys and levers to perform mechanical work, its channels for distribution of food and drainage of sewerage, its means of regulating its temperature and adapting its actions and functions to its varied environments and needs. Its nervous system and the eyes, ears, etc. are constant sources of wonder. We regard the radio as a wonderful invention, as indeed it is, but we are all equipped with more wonderful "sending" and "receiving" sets than any radio manufacturer will ever produce. All human inventions have their prototypes in the animal body.

In studying the wonders of the human body, its structures, functions, development, growth, and its varied powers and capacities, it is well to keep in mind that the power, force or intelligence that evolves the adult body from the fertilized ovum is in the body, is part of it and is in constant and unceasing control of all its activities. Whether it is an intelligent power or a blind energy, it works determinately towards the latest results in complexity of structure and function. In development and maintenance, health and disease; the movements of life appear to be guided by intelligence greater often than the conscious intelligence of man.

Vital processes have a definite object and pursue that object with a persistency that knows no let-up. If we view a few of the engineering feats performed by the body in cases of injury and disease we are forcibly struck with the truth of Graham's remark: "In all these operations the organic instincts act determinately, and, as it were, rationally, with reference to a final cause of good, viz., removal of the offending cause." Dr. Walter says: "Vital processes are mental processes. Life begins with thought and ends with it."

Dr. Alexis Carrel utters a similar thought, saying: "If we attribute to tissues an intelligence of the same kind as ours, as mechanists and vitalists do, the physiological processes appear to associate together in view of the end to be attained. The existence of finality within the organism is undeniable. Bach part seems to know the present and future needs of the whole, and acts accordingly." He uses the embryonic development of the eye as an example, but any structure and function of the body would serve equally well. He employs as another example the changes that occur in the vulva and vagina when pregnancy is nearly completed. The tissues of these structures are invaded by fluids and they become soft and extensible. This change in their consistency renders possible the passage of the foetus a few days later. Coetaneous with the vaginal and vulvar changes, the mammary glands multiply their cells and begin to function before the baby is born. They are ready and waiting to feed the newborn. All of these processes are so obviously preparations for future events that it were egregious to argue the point. Similar preparations for the future are made during the entire period of embryonic development. Dr. Carrel says: "Organic correlations take place as easily between different periods of time as between different regions of space."

We do not need to claim rationality for the unconscious or the organic world anymore than we need to claim the same for the forces that control the formation and repair of a crystal. A watchful automatism is in control. Every force in man's body is governed by immutable law which disposes of them to the highest interests of life and which wisely adapts means to ends. Outside the voluntary powers of man, all matters and forces or agencies, are puncticiliously and eternally subject to law. These laws, uniform in all places and all times, shut up the involuntary actions of man's body to their designed ends. The economy of life cannot relax its grasp upon the working powers of man's body and permit these forces to take on wrong or subversive action and thus endanger life. The law of life, itself, cannot become recreant of its high trust and misdirect the forces of life, or any part of them, and by this reason, create discord in the body, disturbing its peace and threatening its destruction. So firmly and indelibly is the law of life impressed with the "instinctive" inclination, or tendency, or actual necessity to maintain life in its highest condition, that it must, at all times, and under all circumstances, employ the power it has--be this more or less--with a wise adaptation to the end in view; the preservation and prolongation of life.

The same adjusting of means to ends are observed in abnormal conditions that arise during life. The organs always improvise means of meeting every new situation. The body replies to all enemies in a specific manner. Dr. Oswald says: "The organism of the human body is a self-regulating apparatus. Every interruption of its normal functions excites a reaction against the disturbing cause. If a grain of caustic potash irritates the nerves of the palate, the salivary glands try to remove it by an increased secretion. The eye would wash it off by an immediate flow of tears. A large quantity of the same substance could be swallowed only under the protest of the fauces, and the digestive organs would soon find means to eject it. The bronchial tubes promptly react against the obstruction of foreign substances. The sting of an insect causes an involuntary twitching of the epidermis. If a thorn or splinter fastens itself under the skin, suppuration prepares the way for its removal. If the stomach be overloaded with food it revolts against further ingestion."-- Nature's Household Remedies, p. 9.

The living organism is abundantly supplied with safety factors. Indeed all physiological activities are adaptive, so that adaptation may assume many forms. When the tissues are damaged by club, knife, bullet, or fire, the organism immediately adapts itself to the new situation. Every thing moves as if a series of measures, some immediate, some delayed, were employed by the body in order to repair the injury. Heterogenous and converging "mechanisms", all turned to the end of reconstructing the destroyed tissues, are set in motion.

If the small intestine is cut, or part of it removed and the ends brought together and sutured, it requires four hours for the plastic exudate that is thrown out to make the joint tight. Despite the regular or routine wave of contraction in the stomach, the sphincter muscle (pyloric valve) holds tight for five hours after suture, before it permits the contents of the stomach to escape into the intestine. Whether we see in this an intelligent or an automatic adaptation of means to ends, we must see that the individual is a whole, and that the adaptive functions extend to all organic systems. One system cannot modify its functions without occasioning correlative changes in all other systems. The nervous system and the organic fluids serve to correlate the organs. Each part of the body adjusts itself to all other parts and all other parts to it. This process of adaptation is essentially teleological.