them under the present section. The salivary glands, are situated behind, and below, the lower jaw; and their office is to secrete the saliva; which serves to moisten the food, during mastication, and to aid the processes of deglutition, and digestion.

The largest of all the glands is the liver; which lies immediately beneath the diaphragm, mostly on the right side of the abdomen, and partly covering the stomach. It consists of three lobes; and its use is to secrete, or elaborate the bile or gall; a greenish, bitter fluid, which it forms from the blood, and discharges into the gall-bladder, whence it is conveyed to the chyme in the duodenum. The pancreas, called in brutes the sweetbread, is also a glandular body, situated behind the stomach, and secreting the pancreatic juice; which resembles saliva, and which goes with the bile, to modify the chyme, and assist in the formation of chyle, for the recruiting of the blood. The spleen, or milt, is a sponge-like organ, much smaller than the liver, and situated below the diaphragm, on the back and left side. It contains numerous blood-vessels, and its cells are usually filled with blood; from which some have supposed it to be a reservoir or safety vessel for the blood; but others regard it as subservient to digestion, by occasioning an increased secretion of the gastric and pancreatic juices. The kidneys, are small glands, whose office is to secrete or separate superfluous and noxious fluids from the blood, and discharge the same through the ureters into the bladder. If this action be prevented for a long time, as by disease, the result is fatal to the patient.

We have only room remaining to speak of the Voice, which can hardly be studied under any of the preceding divisions of Andronomy. The voice is produced by means of air expelled from the lungs ; though imperfect sounds may also be produced during inhalation. Thus, the lungs serve the double purpose, of respiration, and of articulation, or speech. The air vessels of the lungs, unite, on leaving these viscera, in two tubes called the bronchi, which, ascending, also unite, to form the trachea, or windpipe; situated in front of the esophagus, or gullet; which is also in front of, and attached to, the spinal column. The principal organ of the voice, is the larynx, at the upper end of the windpipe, opening into the pharynx, just behind the root of the tongue, and often causing, by its size, a remarkable protuberance in the front part of the neck. The larynx, owes its vocal powers to the arytenoid cartilage; the two opposite sides, or edges of which, when nearly closed together, are made to vibrate, like a reed, by the air passing between them. The opening which they form, is called the glottis; and the cartilage at the root of the tongue, which falls back, when we swallow, and thus prevents the food from entering the windpipe, is called the epiglottis. The part performed by the other organs of speech, has already been alluded to, in giving the classification of articulate sounds under the head of Phonology. (p. 43).

CHAPTER II.

PHARMACOLOGY.

PHARMACOLOGY, is that branch of Androphysics which treats of medicines; including the modes of preparing them; their properties; and their uses. The name is derived from the Greek papuazov, which may signify either a medicine or a poison: as many of the most important medicines, from their powerful action, would necessarily be poisonous to a healthy person, especially if taken in large quantities. A medicine may be defined as any substance applied to the animal system, either externally or internally, to cure disease, or restore health. The art of comparing and compounding medicines, is termed Pharmacy; the person who prepares them, an apothecary; the book which describes them, a dispensatory; and the medicines themselves, as well the study of them, are sometimes termed Materia Medica. The study of poisons, and their antidotes, is called Toxicology; and is here included in the present branch of Androphysics.

We think it proper to notice a prejudice which prevails, with many persons, against the use of any mineral substance, as an internal medicine. This prejudice supposes that all mineral substances are injurious to the system: whereas, even vegetables themselves, contain several of the mineral medicines. The human body, in a healthy state, contains salts of potassa, soda, lime, magnesia, and iron; equally powerful with the salts administered by the physician. Even our common salt, contains elements, which, when disunited, would be as virulent and noxious to swallow as almost any compound which the chemist can prepare. While, therefore, mineral medicines, as well as vegetable, may be abused, by being given too frequently, or in excess; they are, doubtless, to be ranked among the most important, and in some cases, as the only remedies, which can combat the disease, or give the least promise of recovery.

The preparation of medicines was, in the earliest times, made by the physicians themselves: but it first became a distinct branch of medical science, at Alexandria, about 400 B. C. Mantias, a pupil of Herophilus, seems to have been the author of the first systematic treatise on Pharmacology; and even kings, as Attalus of Pergamus, and Mithridates of Pontus, devoted themselves to the study and invention of medicines. Heras, of Cappadocia, appears to have written the first work on Pharmacy at Rome, 49 B. C.; and Andromachus, the physician of Nero, has left a description of the theriaca; an electuary, or treacle, composed of about seventy different ingredients, long famous as an antidote against poison. Dioscorides wrote a work on Materia Medica, evincing much discrimination; and Galen proposed a classification of medicines, founded, however, on his theory of temperaments, and therefore, long since discarded.

The Arabian alchemists introduced several new chemical medicines; among which were mercury and its preparations: but the prin

cipal pharmaceutical work of the middle ages, was the Antidotarium, published by Prapositus, of Salerno, as early as the twelfth century Paracelsus, the founder of the chemical party in medicine, published a work on the medical virtues of antimony; and brought that article into extensive use. The Dispensatory of Valerius Cordus, published in 1542, was long used as a guide in compounding medicines; but the Fundamenta Materia Medicæ, of the German Cartheuser, founded on the improvements then already made in botany and chemistry, introduced a new and more scientific era, in the present branch of medical knowledge. In France, this science was promoted by the labors of Chomel and Geoffroy; and in England, the treatise of Lewis, improved by Dr. Aiken, contributed much to its advancement. A superior classification of medicines has since been proposed by Dr. Young; and modified by Dr. A. T. Thompson: nor should we here omit to mention the U. S. Pharmacopeia, prepared by a convention of physicians, as a work of high authority; and the Dispensatory of Drs. Wood and Bache, as one of sterling value. We proceed to treat of Pharmacology under the heads of Therapeutics; Materia Medica; Pharmacy, and Toxicology.

§ 1. Under the head of Therapeutics, we would treat of the classification of medicines, in reference to the manner in which they act, or the effects which they produce, on the human system. The classification here presented, is drawn chiefly from Dr. Dunglison's recent and valuable treatise on Therapeutics. In reference to their mode of action, medicines are classed as either vital, chemical, or mechanical agents. The vital agents, are those which directly affect the functions of life; acting either as excitants, which increase, or sedatives, which diminish organic action. The chemical agents, are those which produce an immediate chemical change, favorable to health; and the mechanical agents, are so called, because they are supposed to act mechanically, in producing their peculiar effects.

The excitant medicines, are farther subdivided into several orders, if we may use the term; according to their peculiar effects. The stimulants, or excitants proper, are those which transiently increase the vital action, whether locally or generally; including carminatives, or remedies against flatulence, or wind in the stomach. Tonics, not only excite, but permanently invigorate the system; including anthelmintics, or medicines to expel worms. Emetics, are medicines used to produce nausea and vomiting; and cathartics, are used for loosening, or cleansing the system; being called laxatives, when gradual; purgatives, when sudden; and drastics when severe, in their operation. Diaphoretics, or sudorifics, are used to produce perspiration; diuretics, to increase the secretion of the kidneys; errhines, to produce sneezing, or nasal secretion, sometimes relieving the head; and expectorants, to remove obstructions of the air passages, and of the lungs. Sialo logogues, are medicines which increase the secretion of saliva. Sorbefacients, are employed to cause the absorption and removal of superfluous, or noxious fluids: revellents, among which are rubefacients and vesicants, producing local irritation and blisters, serve thereby to reduce the diseased action of other parts: and antispasmodics, on a similar principle, remove muscular contrac

tion, by relaxing the nerves which produce it. Astringents, are sometimes used internally as tonics, to give strength; but more frequently as styptics, to contract the muscular fiibres, and arrest the effusion of blood.

The sedative medicines, include sedatives proper, which, acting on the nerves, or on the vascular system, diminish vital action; also narcotics, which first excite and then diminish nervous action, producing, in sufficient doses, lethargy or stupefaction; also refrigerants, which reduce morbid heat, or heat caused by disease; and finally nauseants, which by producing nausea, flow of saliva, and perspiration, allay morbid action. The Chemical agents, are antacids, used to counteract acidity, particularly in the stomach; antalkalies, used to counteract alkalinity; antilithics, designed to prevent, and lithontriptics, to remove, urinary calculus, or stone in the bladder; and disinfectants, used either for fumigation, to purify the air, or as antiseptics, to prevent putrefaction or mortification. The Mechanical agents, are demulcents, which sheathe sensitive parts from irritation; including emollients, which soften the parts, or render them more flexible; and diluents, which serve merely to dilute the animal fluids, or render them thinner and less irritating.

§ 2. To Materia Medica, belongs the description of all simple medicines, and their medical properties. We shall here classify them, so far as we have room to mention them, according to the order established in the preceding section. Among the stimulant medicines, may be mentioned alcohol; either concentrated, as in spirits of wine; or diluted, as in distilled liquors; or modified by other substances, as in wine and other fermented liquors. Next to this, are ether; camphor; and the essential oils, as of peppermint, or turpentine; all of which are similar compounds of carbon, hydrogen, and oxygen. Ammonia, and its carbonate, which latter is known as hartshorn, sal volatile, or smelling salt, are stimulant and antacid at the same time. Mercurial medicines, as calomel, and red precipitate, are powerful stimulants, which should be used with the greatest caution. Heat, electricity, and some mental emotions, may also be classed with the stimulant medicines.

Among the tonic medicines, are cinchonia, and quinia, sometimes called quinine; as also their salts; all obtained from Peruvian bark; and found to be most important remedies in certain fevers. Several astringent barks and roots, have tonic properties; as nutgalls, quassia, and snake root: and several astringent salts,-of iron, copper, and zinc, particularly the sulphate of iron, and its carbonate found in chalybeate waters, belong to this class of medicines. Exercise, and cheerful emotions, have also a tonic effect. Among the anthelmintics, are Carolina pink root; and cowhage, which is the down of a tropical plant. The powder of tin, probably acts mechanically to destroy intestinal worms; but as it is often poisonous, its use can in no case be recommended.

The most common emetics, are tartar emetic, the double tartrate of antimony and potassa; and ipecacuanha, the active principle of which, called emetia, is milder than the preceding. Lobelia, or Indian tobacco, and sanguinaria, or blood root, have also emetic proper

ties. Among the stronger cathartics, are elaterium, colocynth, gamboge, and aloes; but one more frequently used is Epsom salt, or the sulphate of magnesia. Pure magnesia, and its carbonate, are milder cathartics; the former being an excellent laxative. The most important vegetable cathartics, are castor oil, obtained from the castor bean; and rhubarb, and jalap, which are the roots of foreign plants. Calomel, or the protochloride of mercury, is both a purgative and anthelmintic; or, if taken in very small dose, it has general stimulant and alterative effects; like those of metallic mercury, and its oxide, in the blue pill.

Among the reputed diaphoretics, are ipecacuanha, and tartar emetic, when taken in very small quantity. The former, mixed with opium and sulphate of potassa, forms the sudorific medicine called Dover's powder. The acetate, and carbonate of ammonia; and nitric ether, often called sweet spirits of nitre; also produce perspiration and better than these, in some cases, are warmth, exercise, and friction. Among the diuretics, are several salts of potassa and soda; and several vegetables; as the meadow saffron, foxglove, juniper berries, and squills. The principal errhines, are snuff, euphorbium, and white hellebore: and among the expectorants, we may name ammoniac, assafœtida, squills, and the balsams of Peru and Tolu. Inhalations of ammonia, vinegar, or tar, in the state of vapor, may also promote expectoration. The chief sialogogues are tobacco, horse radish, and the sweet flag; the habitual use of which is however injurious to digestion. The mercurial medicines also act as sialogogues, when taken in sufficient quantity.

Among the sorbefacient medicines, are iodine, bromine, ammoniac, and galbanum and absorption of the fluids may also be promoted by compression, or friction. Of revellent medicines, ammonia, mustard, cayenne pepper, and Burgundy pitch, are used as rubefacients, producing local excitement or irritation. The Spanish fly is sometimes used as a vesicant, to raise blisters; and Croton oil, as a suppurant, producing pustules or sores. Lunar caustic or the nitrate of silver, and lapis causticus, or caustic potassa, are used as escharotics, for removing unsound flesh. Among the antispasmodics, are castor; musk; assafoetida; and sulphuric and nitric ethers; which exert a peculiar soothing effect on the nervous system.

Of sedative remedies proper, venesection, or blood-letting, is most frequently employed; though it should be with caution. The inhalation of diluted nitrogen, hydrogen, carbonic acid, or carburetted hydrogen gases, has also a sedative effect. Among the narcotics, opium, or its active principles, morphia and narcotina, are frequently used. Laudanum, is a strong tincture, or alcoholic infusion of opium; and paregoric, is a much weaker tincture of opium, with camphor, and other ingredients. The ethers, may have a narcotic effect, as in Hoffman's anodyne; and hops, and tobacco, are also used as narcotics, both externally, and internally. The refrigerants most employed, are cooling drinks, or cold external applications. Nitre, and borax, have also a cooling influence, in proper cases. The nauseant medicines, are chiefly emetics administered in very small doses.