Part 16

3. The word chemistry is supposed to be of Egyptian origin, and, in its primary application, was the same with our phrase natural philosophy. Its meaning was afterwards restricted to the art of working those metals which were most esteemed. In the third century, it came to be applied to the pretended art of transmuting baser metals into gold. The science, in the latter sense of the word, was eagerly cultivated by the Greeks; and from them it passed to the Arabians, who introduced it into Europe under the name of alchemy.

4. The professors of the art were dignified with the appellation of alchemistic philosophers, and the leading doctrine of the sect was, that all metals are composed of the most simple substances; and that, consequently, base metals were capable of being changed into gold; hence, the chief object of their researches was the discovery of an agent, by which this great change was to be effected. The substance supposed to possess this wonderful property was called "the philosopher's stone;" the touch of which was to change every kind of metal into gold.

5. The greatest rage for alchemy prevailed between the tenth and sixteenth centuries. The writers on this subject who appeared during that period, are very numerous, most of whom are unintelligible, except to those initiated into the art. Many of them, however, display great acuteness, and an extensive acquaintance with natural objects. They all boast, that they are in possession of the philosopher's stone, and profess the ability of communicating a knowledge of making it to others.

6. Their writings and confident professions gained almost implicit credit, and many unwary persons were thus exposed to the tricks of impostors, who offered to communicate their secret for a pecuniary reward. Having obtained the sum proposed, they either absconded, or wearied out their patrons with tedious and expensive processes.

7. Chemists, for a long time, had supposed it possible to discover, by their art, a medicine which should not only cure, but prevent all diseases, and prolong life to an indefinite period, even to immortality. This notion gradually becoming prevalent, the word _chemistry_ acquired a more extensive application, and embraced not only the art of making gold, but also that of preparing "the universal medicine." Some of these visionary men asserted, that the philosopher's stone was this wonderful panacea.

8. Few readers need be informed, that the researches for the philosopher's stone, and the universal remedy, were, at length, abandoned, as fruitless and visionary; yet the numerous experiments which had been instituted on these accounts, were attended with the incidental advantage of a considerable dexterity in the performance of chemical operations, together with the discovery of many new substances and valuable facts, which, without these strong incentives, would have remained, at least, much longer in obscurity.

9. Although none of the medicines, produced in the chemical laboratory, answered the chimerical expectations of the chemists, in curing all diseases, and in rendering the perishable body of man immortal, yet they proved sufficiently valuable in the healing art, to command the attention of the profession all over Europe. The adoption of chemical medicines, however, was, at first, everywhere opposed, either as unsafe remedies, or as being inferior in efficacy to those which had been used for so many centuries.

10. These prejudices having given way to the light of experience, chemical medicines came, at length, to occupy a conspicuous place in the Materia Medica; and their value within the present century has become still more manifest. One of the most useful branches of chemistry, therefore, is to make the various preparations used in the medical art.

11. The most efficient agent in the introduction of chemical medicines, was Theophilus Paracelsus. This singular individual was born near Zurich, in Switzerland. Having studied chemistry under two masters, he commenced a rambling life, in pursuit of chemical and medical knowledge; and, having visited Italy, France, and Germany, where he met with many whimsical adventures, which contributed greatly to advance his reputation, he was elected, in 1527, to fill the chair of chemistry, in the University of Basle.

12. One of the first acts of this arrogant professor was to burn, with the utmost solemnity, while seated in his chair, the works of Galen and Avicenna, declaring to his audience, that if God would not impart the secrets of physic, it was not only allowable, but even justifiable, to consult the devil. He also treated his contemporaries with the same insolence, telling them, in a preface to one of his books, that "the very down on his bald pate had more knowledge than all their writers; the buckle of his shoes more learning than Galen and Avicenna; and his beard more experience than all their universities."

13. It could not be expected, that a man with such a temper could long retain his situation; and, accordingly, he was driven from it, in 1528, by a quarrel with those who had conferred the appointment. From this time, he rambled about the country, chiefly in Germany, leading a life of extreme intemperance, in the lowest company. Nevertheless, he still maintained his reputation as a physician, by the extraordinary cures occasionally effected by his powerful remedies; although his failures were equally conspicuous.

14. But the most signal failure of his remedies occurred in his own person; for, after having boasted for many years of possessing an elixir which would prolong life to an indefinite period, he died, in 1541, at Salzburg, with a bottle of his immortal catholicon in his pocket. The medicines on which Paracelsus chiefly relied, were opium, antimony, and various preparations of mercury. He has the merit of applying the last, especially, to cases in which they had not been before used; and upon this circumstance, his great reputation depended.

15. We have been thus particular in noticing this individual, because he was the first who gave public lectures on chemistry in Europe, and because he gave the first great impulse in favor of chemical medicines. He also carried his speculations concerning the philosopher's stone and the universal remedy, to the greatest height of absurdity; and, by exemplifying their inutility and fallacy in his own person, he contributed more than any one else to their disrepute, and subsequent banishment from the science.

16. Researches for the philosopher's stone, and the universal remedy, having been, at length, relinquished, the chemical facts which had been collected became, in the general estimation, a heap of rubbish of little value. At this time, there arose an individual thoroughly acquainted with these facts, and capable of perceiving the important purposes to which they might be applied.

17. The name of this individual was John Joachim Becher. He published a work in 1669, entitled "Physica Subterranica," by which he gave a new direction to chemistry, by applying it to analyzing and ascertaining the constituent parts of material bodies; and his system is the foundation of the science, as it now exists.

18. George Ernest Stahl, a medical professor in the University of Halle, adopted the theory of Becher, and, after his death, edited the work just mentioned; but he so simplified and improved it, that he made it entirely his own; and, accordingly, it has always been distinguished by the appellation of the Stahlian theory. The principal work of Stahl, on this subject, was published in 1729; and, since that time, chemistry has been cultivated with ardor in Germany, and in other countries in the north of Europe.

19. In France, chemistry became a fashionable study, about the middle of the eighteenth century. It had, however, been cultivated there by a few individuals, long before that period. Men of eminence now appeared in all parts of the kingdom, and discoveries in the science were made in rapid succession. Some attention was also paid to it in Italy and Spain.

20. In Great Britain, this subject attracted but little attention, except from a few individuals, until Dr. Cullen had become professor of the science, in the University of Edinburgh, in 1756. This accurate investigator of natural phenomena, succeeded in enkindling an enthusiasm for chemical investigations among the students; and the subsequent experiments of Dr. Black, Mr. Cavendish, Dr. Priestley, and Lavoisier, which resulted in the discovery of the constituent parts of air and water, diffused the same ardor through every part of the kingdom.

21. Lavoisier, the celebrated French chemist, having proved the Stahlian theory to be incorrect, founded another on the chemical affinities and combinations of oxygen with the various substances in nature. This system has been generally adopted; since it explains a great number of phenomena more satisfactorily than any other ever proposed. The great chemical agent, in the Stahlian system, was supposed to be an inflammable substance, which was denominated by the theorist _phlogiston_. To distinguish, therefore, the new theory from the one which it superseded, it was called the pneumatic, or anti-phlogistic system.

22. In 1787, a new technical nomenclature was devised, by the aid of which all the chemical facts are easily retained in the memory. Twelve or fifteen terms have been found sufficient for the foundation of a methodical language; and, by changing the terminations of these radicals, or by prefixing certain words or syllables, the changes that take place in bodies are clearly expressed. This valuable innovation originated with Lavoisier and three other French chemists.

23. In the present century, many important discoveries have been made in this science; and, among those who have been distinguished for their researches into its mysteries, Sir Humphrey Davy, of Great Britain, shines pre-eminent. In the United States, it has many able professors; among whom are Professors Hare and Mitchell, of Philadelphia, Torrey, Renwick, and Draper, of New-York, Henry, of Princeton, Beck, of Albany, Silliman, of New-Haven, and Johnson, of Middletown.

24. Chemistry is so extensive in its application, that we will not attempt to describe any of the operations of the laboratory. We, therefore, conclude this article by recommending this science to general attention; assuring the uninitiated, that it is beset with fewer difficulties than they are apt to suppose, and that every effort in the course will be attended with interesting facts and phenomena, which will abundantly reward the labor of investigation.

THE DRUGGIST AND APOTHECARY.

1. The druggist is a wholesale dealer in drugs, which, in commerce, embrace not only articles used or recommended by the medical profession, but also spices, dye-stuffs, and paints. The commodities of his trade are obtained from almost every quarter of the globe; but especially from the countries bordering upon the Mediterranean Sea, and from the East Indies and Spanish America.

2. The chemist looks to the druggist for most of the materials employed in his laboratory; and from him the apothecary, physician, and country merchant, obtain their chief supply of medicines. There are, however, but few persons in the United States, who confine themselves exclusively to this branch of business; for most of the druggists are also apothecaries, and sometimes operative or manufacturing chemists.

3. Medicinals, when they come into the warehouse of the druggist, are usually in a crude state; and many, or most of them, must necessarily undergo a variety of changes, of a chemical or mechanical nature, before they can be applied in practice. The art by which these changes are effected is called Pharmacy, or Pharmaceutics; and the books which treat of pharmaceutical operations are denominated Pharmacopoeias, or Dispensatories.

4. The operations of Pharmacy, which depend upon chemical principles, are conducted chiefly by the operative chemist; but those which consist merely in mechanical reduction, or in mixing together different ingredients, to form compounds, belong properly to the vocation of the apothecary.

5. The apothecary sells medicines in small quantities, prepared for application. Many of the standing compound preparations which have been authorized by the Pharmacopoeias, and which are in regular demand, he keeps ready prepared; but a great proportion of his business consists in compounding and putting up the prescriptions of the physician, as they are needed by the patient.

6. In country places, where there are generally no apothecary-shops, the physicians compound and prepare their own prescriptions; but in cities, where these establishments are numerous, the medical profession prefer to rid themselves of this trouble. In most cases, however, they keep by them a few remedies, which can be applied in cases of emergency.

7. In Great Britain, the apothecary is permitted to attend sick persons, and administer medicines either according to his own judgment, or in conformity with the directions of the physician. He is, therefore, a physician of an inferior order; and, as his fees are more moderate than those of the regular profession, his practice is extensive among persons who, from necessity or inclination, are induced to study economy.

8. The apothecaries in England, Scotland, and Ireland, are obliged to make up their standing medicines according to the formulas of the Dispensatories adopted in their respective countries; and their shops are subject to the visitation of censors, who have authority to destroy those medicines which they may consider unfit for use; so that unwholesome or inefficient remedies be not imposed upon the sick. The apothecaries' halls, in France, are also under the supervision of the medical faculty.

9. In the United States, there is no censorship of this kind established by the public authorities; yet the physicians are careful to recommend apothecaries, in whom they have confidence, to prepare their prescriptions. The professors in our medical schools are, also, particular in naming to their students those druggists whom they consider men of honor; and omit, at least, to name those who have been detected in selling adulterated medicines.

10. We have, also, an incorporated college of pharmacy both in New-York and Philadelphia, and in each of these, chemical and pharmaceutical lectures are delivered by regular professors. These institutions, although of recent origin, have exerted an important influence in reforming and preventing abuses in the preparation of medicines; and public opinion, especially in the cities, is beginning to render it important for students in pharmacy to obtain a degree from one of these colleges. Under the auspices of the institution at Philadelphia, is published a quarterly journal, devoted to pharmaceutical science.

11. A Pharmacopoeia for the United States was formed at Washington, in 1820, by a delegation of physicians from the principal medical societies of the Union. A revision of this work is expected to be made every ten years. Dispensatories, as they exist in this country, are founded upon the Pharmacopoeias, and may be properly considered commentaries upon them, since the former contain the whole of the latter, together with more minute descriptions of the sensible and real properties of the medicines, as well as their history and exact mode of preparation.

THE DENTIST.

1. The human family is subject to a variety of diseases in the teeth, which generally cause the final destruction or loss of these important instruments, unless judicious remedies are applied in proper season. These remedies are administered by the dentist.

2. There are few persons, in proportion to the great mass of the people, who seem to be aware of the utility of dentistry; for, taking the United States together, not more than one person in a hundred ever resorts to the professors of this art, with the view of obtaining a remedy for any dental disease with which he may be afflicted. The common sentiment seems to be, that diseases of the teeth, and their final loss, at different periods of life, are inevitable inconveniences, to which we must submit with the same philosophy with which we meet other misfortunes.

3. To enable readers who have never examined this subject, to comprehend its general nature, we will give a slight sketch of some of the irregularities and diseases to which the teeth are liable, and, as we proceed, speak of the remedies applied by the dentist.

4. Two sets of teeth regularly appear, at different periods of life; one in infancy, and the other, at a later period. The first set consists of twenty, and the second of thirty-two teeth; the former are called _infant_, and the latter _adult_; and all these, at the age of six or seven, are upon the jaws at the same time.

5. At the age just mentioned, the infant teeth begin to give way to those which lie deeper in the sockets, and which are designed to supersede the former. As the new teeth advance, the roots of the first are absorbed; and, after having been thus deprived of their support, they are easily removed; sometimes, by a slight pressure of the tongue.

6. In a majority of cases, the whole process is carried on by nature with the utmost regularity; but, as she is not uniformly successful in this operation, there is no other period at which the teeth of children require so much attention and care. Sometimes the second set rise in the socket without causing the absorption of the roots of the first. In such cases, the former approach in an improper direction; and, unless the latter are removed in season, deformity will be the consequence.

7. When, however, these precautions have been neglected, and the teeth stand in an irregular manner, they can sometimes be reduced to symmetry by the dentist, without occasioning much pain. When the front teeth are too much crowded by reason of the restricted dimensions of the jaw, the small teeth, situated next behind the eye, or canine teeth, are extracted, one on each side, to give room to the rest.

8. From the ages of six to fifteen years, the teeth of children should be examined, at least once in six months, by a dentist, who, if skilful, can seldom fail of rendering these ornaments of the human countenance regular, healthy, and beautiful. It is customary in England and France, for the proprietors of seminaries of learning to employ a dentist to visit their establishments regularly, for the purpose of performing such operations, and of administering such remedies, as their pupils may require.

9. The teeth are composed of very hard bone and enamel. The latter is a substance exceeding in density any other in the body. It covers the crown of the teeth, and is thickest in those parts which are most exposed to forcible contact in mastication; but, in no place, is it more than the twelfth of an inch in thickness.

10. The most common disease of the teeth is _caries_, or decay, and almost every part of them is liable to be affected by it, but especially the sides of those in front, and the crowns of those on other parts of the jaws.

11. The disease begins its attack either on the enamel or on the bony portion, and gradually extends itself over the tooth, until it reaches the nerves which supply its natural cavity. These having become exposed to the sudden changes of temperature, and to the contact of extraneous substances in mastication, pain and inflammation are produced, and the extraction of the tooth very commonly becomes the only means of relief.

12. All persons are more or less subject to this disease, but some much more than others; and caries of a peculiar character has been so often traced through whole families, from one generation to another, that it is considered hereditary, as much as any other disease to which the system is liable. In many cases, caries seems to be the effect of some serious disease which affected the constitution, while the teeth were in the early stages of formation.

13. Although the teeth of some individuals possess but little durability, and, when caries attacks them, go on rapidly to decay, in spite of all the aid which science and skill can afford, yet, there are comparatively but few instances in which seasonable and judicious treatment will not arrest the progress of the disease.

14. When the teeth are but slightly affected with caries, especially on the sides, a cure may be accomplished by the removal of the decayed portion. This is effected, by the most approved dentists, chiefly with small cutting instruments. Formerly, the file and the saw were employed for this purpose; and, by their indiscriminate and injudicious use, many teeth were ruined, and the art of dentistry itself brought into disrepute.

15. Notwithstanding the injuries which have been inflicted by the improper application of the saw and file, in some instances they are indispensable; and, in the hands of the scientific operator, they need not be feared. They are especially useful in preparing the way for the employment of other instruments; for, in some cases, the affected part can with difficulty be reached by any other means. But filing the teeth for the purpose of improving their appearance, or for rendering the sides more accessible to the tooth-pick and brush, seems to be reprobated by the most intelligent part of the profession.

16. When the caries has penetrated far into the tooth, and, in its removal, a cavity of suitable form and dimensions can be produced, it is filled with some substance, with the view of protecting the bone from the action of extraneous agents. The dentist is careful to remove every particle of the decayed portion, and to render the cavity perfectly dry by repeated applications of lint or raw cotton, before he attempts to fill it.

17. Gold is the only substance which possesses sufficient solidity to withstand the ordinary friction of mastication, and which, at the same time, is capable of resisting the chemical action of the substances that come in contact with it; yet lead and tin are frequently employed; and many have been made to believe that they answer as good, if not a better purpose, than gold itself. The durability of these metals, however, can never be depended upon, and they ought not to be employed, where the tooth is capable of resisting the mechanical force required to fill it properly with gold.

18. The metal is prepared for the use of the dentist by the gold-beater, in the manner described in the article which treats upon the business of the latter. The leaves, however, are not beaten so thin as those designed for the common purposes of the arts. The portion to be applied is cut from the leaf, and, after having been twisted a little, is forced into the cavity. The metal is rendered perfectly solid by means of instruments adapted to the purpose.

19. This operation, properly performed under favorable circumstances, generally renders the tooth as serviceable, to the end of life, as if it had never been diseased. The hopes of the patient, however, are sometimes disappointed by the unskilfulness of the operator, or by the general unhealthiness of the mouth, arising from tartar, other decayed teeth, or want of care in keeping them free from the lodgment of particles of food.

20. It is a common practice to have teeth extracted, when they are affected with pain; but this operation is not always necessary. In many cases, the nerve can be paralyzed, and the tooth plugged. By these means, teeth which, under the ordinary treatment, would be prematurely sacrificed, are often retained, for years, in a serviceable state.