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on his work, performed the first modern dissection which has led to permanent results. The purity of his intentions, and the noble views which animated him, have helped to remove the scales from the eyes of law-makers and to destroy the deep-rooted prejudice which ranked dissection among the works of darkness. Ambrose Pare was the first to turn to practical account, in surgery, the labors of his predecessors, and by his position as surgeon to several European sovereigns was enabled to obtain widespread notoriety for the principles he taught and practised. Paré systematized the disconnected researches of former surgeons, and made the first valuable contributions to the magnificent structure since reared by John Hunter, Dupuytren, Abernethy, and Sir Astley Cooper.
Similar progress marked the other branches of the science, especially obstetrics, which was rescued from the hands of empirics by the labors and studies of Saxtroph of Copenhagen, and Solayres de Renhac of Montpelier. The last century and the commencement of the present were marked by numerous and important improvements in every department of medicine; and both Great Britain and the Continent furnished many names which will live for ever in the archives of the science. Italy boasts the names of Lancisi, Morgagni, Monteggia, Scarpa and Asselini ; Holland, Albinus, Camper, and Boerhaave; Germany, Haller, Heister, and Soemmering ; France, Dupuytren and the illustrious Bichat; England, Cullen and the Hunters; while America need feel no shame at the name of Benjamin Rush.
But the labors of those men, numerous and useful as they are, pale before the brilliant wonders of the last forty years. Physical examinations, chemical tests, microscopical histology, and the use of anæsthetics in surgery are but a few of the inappreciable benefits of this century. To present a full tabular statement of the improvements the last forty years have witnessed in every department of medicine, would be a task almost interminable, and altogether beyond our purpose. It is not so much our aim to present striking or original views to professional men, as to interest the general reader in such progressive changes as have elevated medicine to the rank of a science, rendered it a potent agency of civilization, and entitled its patrons to the respect and gratitude of enlightened men. Many persons, even among the better informed, grossly misjudge the character and influence of medicine, measuring it rather by what it has failed to accomplish than by the wonders it
has realized. These people constantly complain that medicine has not more than half covered the field of investigation ; that the subjective portion of the science is jejune, compared with the unlimited domain of the objective ; that mortal
: ; flesh will ache and weary for many a day before medical resources can relieve all the ills to which it is heir. In their estimation, every science is purely constructive, and tends to perfection, not. in proportion to what has been actually accomplished, but to the decreasing demand it may be called upon to meet. Thus, let a new and intricate legal problem arise, and the solution of it will be at once discovered in the existing principles of law, for this is a constructive science, and advances, pari passu, with the requisitions that are made upon it. But how different in medicine—a science based on facts, and not on theoretic principles, and whose field of enquiry is commensurate with the three physical kingdoms of nature. As regards such persons, therefore, our aim is to convince them that in the domain of medical research the human mind has operated with as much activity and success as in any other field, and that the labors of medical enquirers are to be estimated by the positive results reached, and not by the width of ground left unexplored. Moreover, some help may be given to the crusade undertaken in the pages of this Review against an unprincipled class of men who batten on the credulity of the people, by contrasting the solid and profound labors of recognised medical investigators, their great erudition, their conscientious regard for duty, and their consequent reliability, with the glitter and tinsel, the hollowness and immorality of quacks, empirics, and innovators.
The practical applications of medicine depend for success on the knowledge of physiology, which in turn looks to anatomical science for the means of reaching maturity. We may therefore consider. anatomy as fundamental, and must first enquire what developments it has lately received, and how such developments have been effected. Dissection revealed to the enquirers of the last century and the commencement of the present nearly all the facts of anatomy which the unaided eye could discover, so we must look elsewhere for the agent which has enabled later anatomists to make so many and such valuable contributions to science. Such an agent is the microscope. This instrument, , known as far back as the seventeenth century, was for a long time held in light estimation, being considered of no greater
importance than a means of agreeable pastime. Robert Hooke in 1667, and Leewoenhock, whose researches are recorded in the Philosophical Transactions of 1673, first brought microscopy to bear on the sciences and were richly rewarded for their pains. Their few and simple discoveries were hailed as precursive to new and most important enquiries, and the attention of opticians was at once directed to the means of improving the simple instrument hitherto employed. But little progress, however, was effected, even after the introduction of combined lenses, till after the first quarter of the present century, when a means of correcting chromatic aberration was discovered, since which time the instrument has become a power, the grasp and ken of which can be measured but by the marvels it has disclosed, the grand hopes it has realized., It has created a new science in the bosom of anatomy; it has poured a flood oflight on the ultimate structure of animal organization ; so that histology, or the science of tissue-making, is now regarded as the phase of anatomical science most pregnant with truth, most fraught with brilliant hopes for the future. Every tissue of the body has been subjected to the searching gaze of the microscopist, and a collation of results has led to the enunciation of this law, that all living organisms are the products of elementary cells, the differences in which determine the differences of the product. The influence of this law on physiological researches may be appreciated when we state that every difference of structure implies a difference of function ; whence it is to be inferred that tissues which the naked eye proclaims identical in structure and in functions differ in both those respects when the microscope has revealed a difference in their primordeal cells. Of the application of these laws we have a striking illustration in the mucous and serous membranes of the body, touching which some physiologists and anatomists maintain that the knowledge of the intimate structure of those tissues would lead a priori to a knowledge of their functions. Cells in general consist of an outer wall, a contained substance, either liquid or solid, and a nucleus. They are differently shaped, being either spheroidal, fusiform, star shaped, caudate, or polyhedral. They develop themselves differently, the difference depending on the results to which they give rise.
The latest microscopists give two fundamental modes of development, the one taking place by a division de novo of the cell itself, the other by the creation of new cells through the operation of the vital forces, in a fluid prepared for that purpose. The secondary modes of development are more numerous, but the chief among them are duplicative subdivision, where the parent cell itself is split, giving rise to two or more new cells ; and endogenous development within the cell, where the nucleus is split and the parent cell perishes. In this manner are all the tissues of the body developed ; and, as has been heretofore remarked, on the characteristics of the shape and the manner of development of a cell depend the peculiarities of the function of the organ which springs from it. Thus microscopy, going back to the ultima ratio of animal organization, has traced, step by step, its successive development from a simple cell to that marvellous structure man, the beauty of the world, the paragon of animals. Not only has the normal growth and structure of the body been revealed by the microscope, but it has thrown wonderful light on the minute changes produced by morbid conditions of the system. In this way it has become an invaluable means of diagnosis and there is a prospect that continued microscopical observations will disclose a peculiarity of cell formation and development in every diseased organ as it has already done in the case of cancerous growths.
The liver and the eye may be taken as type cases of what microscopy has accomplished in the minute anatomy of special organs. The liver, for a long time viewed as a homogeneous mass, suddenly revealed to the eye of the microscopist a structure most complex and beautiful, a symmetry and design everywhere visible, the minutest portion exhibiting on the field of the microscope an arrangement of lobules, cells, nerves, and bloodvessels, that challenged the warmest admiration. To Kiernan and Handfield Jones in Great Britain, and Kolliker in Germany, we are indebted for those interesting microscopical discoveries in this organ. The study of the minute anatomy of the liver immediately wrought a complete change in the physiological views which had been held concerning it, so that it is no longer considered a mere manufactory for bile, but as discharging the far more important role of repairing the waste of nervous tissues. Among the productions of the liver, cholesterine has been especially remarked, and numerous experiments have shown that this substance is much employed in the active processes of the nervous system. Thus the liver, instead of secreting a mere excrementitious substance, for such to a great extent is bile, is invested with the far nobler function of supplying a
waste occasioned by the exercise of our highest faculties. Pathology, ever looking to physiology for new developments, availed itself of this discovery to abandon the use of drugs which had for effect the constant stimulation of the liver, and, as Dr. Van Buren, of the New York University, lately remarked, the day is not far distant when the liver will cease to be considered a mere objective term for calomel.
The eye also offers an instance where the labors of microscopical observers have been brought to bear with the happiest results. The discovery of the retinal expansion of the optic nerve, or Jacob's membrane, has wonderfully helped to elucidate the phenomenon of vision. Those exquisite nerve fibres spread over the retina seemed specially fitted to take cognisance of the delicate undulations of light. Indeed, proceeding on the data furnished by the microscopical anatomy of the eye, Dr. Draper has propounded a theory of color-vision which bids fair to supersede all hitherto received views.
As in every science where the mind has deployed its activity with success, so in anatomy men have passed the limit of the experimental and gone into the region of the speculative and transcendental. We have, therefore, a transcendental as well as a microscopical anatomy; and though the speculations have not as yet assumed a very orderly shape, they at least testify to the ardor with which anatomical science is cultivated. Within that happy mean, those bounds
“Quos utra citraque nequit consistere rectum." Such speculations give forth much that is beautiful and true; but the German medical mind, taking the cue from the philosophy of Fichte and Schelling, has evinced a tendency to transcendentalize beyond measure. Transcendental anatomy has for its object to reduce and simplify organic types, to establish harmony and unity of design in the various forms of animal life, and thus fill the mind with the depth and the riches of that wisdom which has known how to engraft infinite variety on wonderful unity and order. Already one important result of those speculations has been to refer rudimentary organs to this design of nature to preserve unity of type in all her works. Thus the rudimentary mammæ of the male are doubtless for the purpose of rendering less striking the necessary imperfection involved in the distinction of the sexes. Passing now from these reflections, and the countless benefits microscopical labors have bestowed on medical