Egyptiacus, Mundus subterraneus, and the Organon mathematicum. He was also a bold and original thinker, more disposed to pursue his own opinions, than respect the sentiments of others. Though his writings abound with varied erudition, it is evident, that a warm imagination led him to seek the wonderful rather than the useful. With this diposition, at a period when the knowledge of nature was at a very low standard, he professed to explain the origin, cause, and prognosis of the plague, on the animalcular hypothesis. With these writers originated, we apprehend, the doctrine of the materia contagiosa being a living animalcule. In this hypothetical course, Hauptinan and Kircher were soon followed by physicians of reputation for physiological learning, and a knowledge of nature.

Among the earliest of these is found Christian Langius, a French physician, born at Luccau, in the lower Lusace; and who, after quickly reaching the highest honours in his profession, died in 1662, at the early age of 42 years. In an introductory Preface to Kircher's Scrutinum Pestis, published at Leipsic in 1659, Langius probably first made public his opinions on the properties of Animalcula, as producing disease; but his doctrines were more precisely defined in a posthumous work entitled, Miscellanea Medica Curiosa. In this the pathologia animata is supported, not by fact and experiment, but by ingenious arguments drawn 'from the subtleties of scholastic reasoning, and conjectures founded on visionary hypotheses. England has not been without its supporters of this absurd doctrine. In a discourse on the state of health, in the island of Jamaica, published in 1679, the author, Dr. Thomas Trapham, attempts to prove that syphilis and yaws are caused by minute insects; and arrogates to himself the invention of the hypothesis. Dr. Bradley was an advocate for this doctrine, and derived his Animalcula from Tartary. Long after this, Dr. Adam Freer, in an inaugural Dissertation de Syphilitide Venerea, published at Edinburgh, supports a Theory so whimsical, that it is not easy to believe him in earnest. On the authority of Hauptman, Langius, and Bonomo, he assumes the opinion that itch and lues arise from different species of the genus Acarus; and that from the congress of the syphilitic and itch acari, a hybrid variety is produced, giving rise to sivvens. Strange as this way appear, a practitioner, who resided at Sandwich in Keut, and wrote a book with the quaint title of Vermiculars examined, went much further; for he undertakes to

prove,

prove, not only the existence of animalcules in all parts of the human frame, but that they are the cause of all diseases, and that every action of life originates with them. There has never been an opinion so absurd, but some theorist has adopted it with blind enthusiasm./ The ingenious surgeon, Pierre Dessault, of Bourdeaux, believed that syphilis was produced by animalcula, and that mercury proved a specific by the destruction it occasioned among this animated morbid material. In this opinion, like Trapham, he fails in originality; for it is evident, that his idea is taken from an hypothesis of Antoine Dedier, who resided at Montpellier in 1691, and died at Marseilles in 1746, when physician to the gallies in that port. In a dissertation de Morbis Venereis, published in 1723, Dedier argues, that an imperceptible vermis is the cause of syphilis; and that the disease is propagated by the transmission of this animalcule from one subject to another. But his hypothesis does not stop here. He warmly contends that the volatile and spirituous principle in vegetables depend on an assemblage of these worms. Dedier, notwithstanding his eager disposition to theorize, was a man of considerable learning, application, and ingenuity; of an open and ingenuous disposition, communicative of whatever he knew; and while physician to the Hotel Dieu at Montpellier, promptly answering all questions on his profession. It is probable his connection with Raimond Vieussens, whose daughter he married, and who was himself a wild and determined theorist, gave a bias to the mind of Dedier, fatal to his own reputation, and injurious to science.

As we approach nearer to the present times, and to an æra, when inquiries into the history of nature are not directed by the imagination, but by that sober faculty which admits nothing to be true that is not proved by carefully repeated experiments, we shall not find the animalcular hypothesis altogether abandoned. There was published at Vienna, in 1762, a volume, with the title of Opera Medico Physica, in which the author, Maria Antonio Pleniz, insists that bodies which are vulgarly supposed to rot, or to be dissolved by putrefaction, are devoured by myriads of animalcula; that the factor evolved from such bodies arises from the excrements of these animalcula; and that contagion is spread by their being wafted through the air, and carried from,place to place. On this hypothesis, he attempts to account for the appearances in small-pox, measles, scarlatina, and all other contagious diseases.

The

The northern school of science, at the head of which was the immortal Linneus, has given a degree of consequence and credit to the animalcular hypothesis, which it did not, perhaps could not, receive from any other source. When this profound naturalist, in his Exanthemata Viva became the advocate of this doctrine, and supported it by observations scattered throughout his numerous writings, his pupils, who had been accustomed to look on his opinions as incontrovertible, labored to convince the scientific world, that this, the weakest of those opinions, was founded on the rock of truth.

In the Exanthemata Viva, published at Upsal, in 1757, Linneus admits many more insects as the cause of exanthematous diseases than he had seen; and thus, by reasoning from analogy, instead of supporting the theory by known facts, becomes as hypothetical as his predecessors, In an academical oration at Upsal, delivered with a florid rhetoric, perhaps `pardonable on such an occasion, it is observed, that the Supreme Disposer of all Things has given command to those minute animalcules, the Sirones, and the whole man becomes one loathsome contagion. In the same oration, other species of Sirones are alluded to, and denominated the ministers of disease and death; the source of plague, small-pox, spotted fever, and other spreading and infectious disorders.

In the Amenatates Academica, where the above oration is found, Michael A. Baecknor asserts, that dysentery, syphilis, and the contagions that produce exanthemata, are derived from some undiscovered species of acari.

The animalcular hypothesis, when employed to explain the contagions of exanthemata, dysentery, syphilis, and rabies; and to account for the paroxysms of epilepsy and the ravings of mania, rests solely on loose analogies and forced conjectures; and the admission of it generally, would have been fatal to the practice of medicine. Mercury, sulphur, and arsenic, would have been resorted to in all diseases, by physicians under the influence of this hypothesis; and medicines of the most pernicious qualities would have been given in pestis, variola, morbilli, scarlatina, &c. or possibly the principles laid down by a French empiric named Boile, might have superceded rational practice. About 1727, this person maintained at Paris, that all diseases were produced by animalcula in the blood, and different diseases by different animalcula; that

there

that there were other animalcula which were enemies to the noxious ones, and had the power to pursue and destroy them. He pretended to be well acquainted with the noxious animalcula, and with their several enemies, by means of which the sick might be relieved. He asserted also, that he well knew the medicines abounding with the auxiliary animalcules. All this he pretended to demonstrate by a microscope formed for the purpose; but the trick was soon discovered, and the Charlatan fled with his glasses and auxiliary animalcula.

In no other instance within the circle of theoretical speculation, has an hypothesis arisen so little capable of being subjected to practical purposes, as that which derives diseases from living animalcula. It is singular that this opinion, so long since rejected in Europe, should again be promulgated in America. But it is not by hypothesis, however cunningly supported, that improvement in the science of medicine is to be effected; on plain facts only can useful practice be founded.

From these visionary scenes we turn with increasing satisfaction to the sober path of scientific truth. Among the works that come nearest to this standard, we are induced particularly to notice the "Observations on some of the most frequent and important diseases of the heart; on aneurism of the thoracic aorta; on preternatural pulsation in the epigastric region; and on the unusual origin and distribution of some of the large arteries of the human body," by Mr. Allen Burns. A work intended to treat of all the diseases of the heart, should arrange them, in the opinion of Mr. Burns, under three distinct classes.

The first class should contain the sympathetic affections, or those diseases which are dependent on the consent which this organ has with other parts of the body.

The second class, those affections which are brought on by such malconformations of the heart, as give rise to a mixture of the venous with the arterial blood.

And the third, those diseases induced by some organic affection of the heart, which mechanically impairs the circulation, but not necessarily alters the composition or properties of the blood.

The second and third classes only are treated of in this work, in which many cases are inserted, and much prac tical information.

This addition to the history and treatment of the diseases of this important organ, will be properly placed in medical

libraries

libraries by the side of SENAC's admirable Traite de la Structure du Cœur, de son action et de ses maladies.*

This year has produced further Observations upon two of the most dreadful maladies, that afflict mankind, but without much prospect of lessening their fatality. Over cancer and hydrophobia, the medical art has hitherto maintained but little power; this should not, however, deter from investigation. In the cure of these diseases every thing is yet to be learned; their cause remains obscure, and the history of their characteristic symptoms is not sufficiently distinct. It would be desirable to see this investigation marked by attentive observation, by an unprejudiced examination of facts, and having the authority of sober experience instead of wild invention. Upon the first of these calamitous afflictions, carcinoma, and the peculiar tumour which is understood generally to precede it, Dr. Lambe has published "Reports," in which he details the effects of regimen. This physician has long cherished opinions upon the properties and powers of water, that mankind will not very soon be convinced are true. "Water is," he says, " a poison which affects every fibre. of the body; it is the direct and immediate agent in the production of cancer, and may fairly be suspected to be operative in the production of all diseases attended with a solution of continuity." In a former work, to which this may be considered as the sequel, Dr. Lambe endeavoured to prove that all water contains arsenic; and that this is the material that gives to it destructive qualities. By distillation, he considers this fluid to be separated from its arsenical impregnation, and when thus purified, believes, by its constant use to the exclusion of every other potation, cancer may be cured; but he advises as auxiliary to this process a diet of vegetables in their raw state. Whether chronic and constitutional diseases may be mitigated or even cured, by a total change of all the ingesta, is not yet absolutely determined; and it is to be lamented, that Dr. Lambe's inquiry on this point has been generally hypothetical, and but little founded on a course of experi

ments.

* Tissot said of Senac's Work, "Cet ouvrage n'accroit rien laissé a de sirer, si son illustre auteur, en annonçant une second edition, ne nous avoit pas appris, qu'il pouvoit le rendre encore plus parfait. Un grand homme peut se surpasser lui-meme, et voir un point de perfection que les autres ne desirent meme pas." Unfortunately, Senac did not live to produce this corrected and improved edition.