ON IRRITATION AND INSANITY.

FIRST PART.-On Irritation considered in its application to
Health and Disease.

1

CHAP. I.-IDEA OF IRRITATION.

The word Irritation represents to Physicians the action of irritating substances, or the state of the living parts that are irritated. We give the name of Irritants, to all those moders of our bodily economy which increase the irritability, or sensibility of living tissues, and which raise these phenomena beyond their (normal* ) regular degree.

The word Irritation, is applicable to every living body, all of which are endowed with irritability; but in medical language this word is used to designate the unusual increase of irritability, or of sensibility, among the higher order of animals. Our intention is, to consider irritation as applied to man alone, leaving to others the task of applying it to the veterinary art.

To say that a man is capable of irritation, is, no doubt, to say that he is irritable; but the irritability, which is the property of every tissue, is not taken in a pathological, or morbid sense. We express by this word, the property possessed by the tissue, of moving on the contact of a foreign body, which induces us to say, that a tissue has felt that contact. Haller confined this property to the muscular fibre : it is now agreed, that it belongs to every tissue. When a man is conscious of the motions excited by a foreign body, *Normal: within the usual and regular limits of the laws of healthy life. Abnormal what is out of those usual and regular limits from whate

ver cause.

which we frequently call a modifier, he is said to have felt the impression of that body, and we give to the faculty which he possesses of feeling or perceiving it, the name of Sensibility. Sensibility then, belongs to the individual, (Moi,*) and irritability to every fibre of the human body. A part affected by a foreign body, may be excited to motion without the individual (Moi) being conscious of it. In this case, there is nothing but irritability; but if the individual (Moi) experiences that kind of modification which induces the man to say, "I feel, I perceive," there is both irritability and sensibility. Sensibility, then, is the consequence of irritability, and not irritability of sensibility: in other words, we must be irritable, before we are sensible. The embryo is not yet sensible, it is only irritable: an apoplectic man is no longer sensible, but he is irritable. We see that irritability is common to all living beings, from the vegetable to the man, and that it is constant; while sensibility is a property belonging to certain animals only, and is manifested only under certain circumstances; these circumstances are the existence of a nervous apparatus, furnished with a centre, to wit, the brain; there must also be a particular state. or condition of that apparatus, for it is not always in a condition to give to the animal a consciousness of the motions which pass within its tissue. The apoplectic man, and the embryo, are proofs of this.

Some persons have erected into a property, the faculty which the fibre possesses, of yielding to the impression of a stimulant, without the animal himself being conscious of it. They have designated this pretended property, by the phrase Organic Sensibility, because it is in such manner inherent in the organs, that it may be observed in them when separated from the collection; but as the movement of the stimulated fibre is the only phenomenon that is seenas it is impossible to separate, to insulate the feeling from the motion-as the word feeling here, has no other meaning than self-motion-and as by like reasoning, the word feeling may be applied to inert bodies, since nothing hinders us from saying, that the ball which is moved, has felt the contact of the ball which is impelled against it.-This organic sensibility is a superfluous abstraction, which cannot find entrance into the exact language of philosophical physiology.

*Moi: one's self-that which constitutes me a different being from every other thing or creature. This seems, among the French metaphysicians, to be the expression for individual consciousness, personal identity.

Trans!.

The modifiers which put irritability into action, are called excitants, or stimulants, and their effect, excitation or stimulation. Excitation, considered under a general aspect, separate from the place where it exists, and the modifier which produced it, is also called excitement. When excitation, or stimulation exceeds the (normal) ordinary bounds, it puts on the character of irritation, and the agents which produce this, are called irritants. This is the irritation which forms the base of the physiological doctrine in medicine; but prior to considering it pathologically, and before investigating the part that it plays in the production, the course and the treatment of diseases, it may be useful to cast an eye over the eras of medical science, to discover by what gradations we have at length arrived at the point where we find ourselves.

CHAP. II. HISTORY OF IRRITATION.

Hippocrates had no idea of irritation, but he admitted a consent among the organs, which he attributed to an internal principle (enormon) which a modern physician has translated impetum faciens, (producing an impulse ;) by this occult force, he explained the phenomena of health and discase. The dogmatists, who followed the father of medicine, acknowledged a material soul, etherial or igneous, formed of whatever was most subtile in matter, and they made it preside over every vital action: this material soul held its place for a long time among the schools, sometimes alone, and sometimes as subordinate to an immaterial and imperishable soul, but they had no idea of irritability in the living tissue.

Neither is the theory of Strictum and Laxum of Themison, developed by Thessalus, irritation: it related to the facility or the difficulty which atoms experienced, in penetrating into the cavities appropriated to them; and the therapeutics which resulted from these hypothetical speculations, was absurd and without any relation to the modern theories of excitement and irritation. They proposed to open and shut the pores of all bodies which they considered like the skin, upon which they most frequently experimented. Hence they set to work by means of frictions; sometimes executed with substances attractive, sometimes astringent, repulsive, adstrictive, &c. and they emptied the body by vomits, by purgatives, and by regimen; to fill it again within a certain regulated number of hours or days

Men who had no idea of anatomy, or of the functions of the body, conceived that by these practices they could empty all the channels of the system, expel the old matter, and introduce new, more proper to sustain health, and this they termed metasyncrasy, or reincorporation; they flattered themselves that by this pretended regeneration, they could give more force, suppleness, and permeability to the living channels; correct the excess of constriction or relaxation, and place them in that middle condition, most favorable to health and longevity. We see, then, upon what slight foundations it is asserted, that the notion of irritability is founded upon this system.

Galen developed the elementary and humoral theory of which the germs were found in the writings attributed to Hippocrates. He was the father of humoralism-he established forces to act upon the elements, earth, water and air, or pneuma, to convert them into humors, regulate their mixtures and their relations to each other, and enable them to direct the functions of life, and the conservative efforts of nature in disease. He lost himself in subtleties on almost every question he discussed, and had no idea whatever of animal irritability.

The doctrine of Irritation is not to be sought for in the oriental application of magic and the Cabala to the art of healing; nothing is there to be found but what is degrading to the human intelleet.

The Arabians, who cultivated medicine with so much ardour before the invasion of the Turks, were mere copyists or imitators of Galen and the Greeks. They explained all the phenomena of life by occult forces, which they multiplied prodigiously. They were the founders of Materia Medica, and of Chemistry, but they had no idea of Irritation. Dissection was interdicted, and experiment was unknown. They had no anatomy, but that of Aristotle or of Galen, or of the Physicians of the Alexandrian School. Surely it was not from these sources, they could derive any just notions of the vital properties of the human body.

On the revival of letters, some authors, Jerom Fracastorius, for example, spoke of the irritation produced by the humours on the solids; but they built up no system on this vital action. The word Irritation is found among them, merged and lost amid a deluge of expressions, more or less faulty, belonging to the elementary and humoral pathology.

In this author, Irritation is considered in the abstract, and not as seen in this or that part, or as a state of the body.

During the 16th century, and the universal attack on the Galenical Theory, a Professor of the Faculty of Montpelier, Joubert, who first opposed "the dread of a vacuum," made use of Irritation to explain the phenomena of convulsions, which he attributed to the reaction of the solids against the morbific causes. He also attributed the action of medicines to a species of Irritation, viz. the disagreeable impression made on the stomach. Still the humoral pathology predominated; no system was yet founded on the irritability of the animal fibre. This, indeed was not even suspected, though manifest in some of the functions.

The Alchemists, the melters of metals, were for a long time occupied in discovering specifics and panaceas for the cure of disorders. Paracelsus their Coryphæus, imagined a kind of soul attached to the organs and residing in the stomach. He called it Archæus, and gave to it in charge, the government of the functions; but he did not assign to it Irritation as its prime minister, and irritability played no part in his absurd system of galimatias. Yet to one of the votaries of medical chemistry, Van Helmont, we owe the first notions clearly expressed of Irritation. Van Helmont admitted the Archæus of Paracelsus, and like him, placed it in the stomach. This physician was the first who gave a just notion of the local cause of Inflammation. He attributed it to the anger of Archæus, who, offended by the presence of morbid causes, sent a ferment into the part, which the Archæus always had at command. This ferment irritated the tissues, which called upon the blood, and thus became the immediate cause of inflammation. He exemplified this by a thorn forced into a sensible part, and thus gave an idea of the mechanical production of Inflammation. He attributed also to Inflammation some diseases which, till that time, had been very differently considered, such as dysentery, which he placed in the first rank of phlegmasiæ, declaring that it differed from pleurisy, only by the part effected.His notion of the manner in which inflammation was produced occupied the famous article Aiguillon in the Encyclopedie, which has laid the foundation for the modern works on the vitality belonging to each of the organs.

But this idea had not all the success which we might have suspected; for, from the system of Descartes arose the physiologico-chemical school of Sylvius, the mechanico-mathe