Physiological Researches on Life and Death

by Xavier Bichat

It is manifest then that society inverts the natural order of education in the animal life, and that it irregularly distributes to the different organs of this life, a perfection which they would otherwise enjoy in a more uniform proportion.

A determined sum of power, has been attributed to every individual, which sum must always remain the same, whether it be equally or unequally distributed, accordingly the activity of one organ must imply more or less inactivity in the others.

This truth will conduct us to the fundamental principles of all social education whatever; namely, that no individual at the same time, should be applied to many studies, even if it be wished that he should succeed in all of them. Philosophers have long insisted upon this maxim, but I doubt whether the moral reasons on which they have founded it, are all of them together worth this single and beautiful physiological observation by which it is demonstrated, that for the purpose of augmenting the powers of one organ, there are no other means than those of diminishing the powers of the others. On this account I shall dwell upon this observation, and prove its truth by a variety of facts.

The ear, and especially the touch, acquire in the blind man, a perfection which would hardly be credited, were not its reality proved by daily observation. The deaf and dumb possess in the eye an accuracy of sight, which is unknown to those, with whom the powers of the ear and utterance are unfolded. Little connexion with external objects, enfeebles the senses of persons who are subject to ecstasy, but gives the brain a power of contemplation, such as to make it appear, that every part of the animal life, excepting that organ, during such affection is in a state of sleep.

But what occasion is there for seeking in extraordinary facts, the proof of a law which the animal in its healthy state exemplifies at every moment. Let us consider in the series of animals the relative perfection of each organ, and it will be seen at once, that where any one of them is excellent, the others are less perfect. The eagle, which has a very piercing sight, has but a very obtuse sense of smell; in the dog, the latter sense is extremely fine, the former dull. The sense of hearing is particularly acute in the hare, that of touch in the bat; the cerebral action predominates in the monkey, and vigour of motion in the feræ.

Every species then possesses some particular division of its animal life, in a degree of excellence superior to that of the others. Not a single instance will be found, where the perfection of one organ does not appear to be acquired at the expense of the others. Man in general, abstraction being made of every other consideration, has the ear particularly good, and in the natural order of things, this must be so; because his speech, which exercises the ear incessantly, is for this organ a permanent cause of activity, and therefore of perfection. And not only in the animal life is this law remarkable; but it appears to have place also, in all the phenomena of the organic life. The morbid affection of one of the kidneys, of one of the parotid glands, will double the secretion of the other.

Let us now examine what happens in the process of digestion. Each system at such time is the seat of an exaltation of the vital powers. Immediately after the entry of the aliments into the stomach, the action of all the gastric viscera is augmented, the powers of life are concentrated about the epigastrium, and abandon the organs of the external life; from thence arise, as authors have observed, the lassitude, the inaptitude of the senses to the reception of external impressions, the tendency of the individual to sleep, and the cold which is so frequently felt in the integuments.

The gastric digestion being completed, the vascular succeeds, and the chyle is introduced into the circulatory torrent, for the purpose of undergoing the influence of this system, and that of respiration; accordingly the blood-vessels and lungs become in their turn, the focus of an increased action, the pulse rises, and the movements of the thorax are precipitated.[47]

It is then the glandular, then the nutritive system which enjoy a marked superiority in the state of their vital powers. Lastly, when these powers have been successively developed, over all the system, they return to the organs of the animal life, the senses resume their activity, the functions of the brain their energy, the muscles their vigour. Whoever reflects upon what he has experienced after a somewhat copious repast, will be easily convinced of the truth of these remarks.

In this way, the whole of the functions represent a species of circle, of which the one half belongs to the organic, the other to the animal life, the vital powers seem successively to traverse these two halves. When they are found in one half, the other is proportionably deprived of them, nearly in the same manner as every thing appears to languish and be reanimated in the two portions of the globe, accordingly as the sun refuses, or sheds down his beneficent influence.