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العربية | català | 中文 | 中國傳統的 | français | Deutsche | עִברִית | हिंदी | bahasa Indonesia | italiano | 日本語 | 한국어 | မြန်မာ | Pilipino | Polskie | português | ਪੰਜਾਬੀ ਦੇ | Română | русский | Español | Swahili | Svensk | ไทย | Türkçe | اردو | ייִדיש | Tiếng Việt These external translations are automated and may not be accurate. (More? About Translations) |
Williams HS. A History of Science. (1904) Harper and Bros. New York.
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18th Century Anatomy and Physiology Part 1
Modern Development of the Chemical and Biological Sciences
Albrecht von Haller
An epoch in physiology was made in the eighteenth century by the genius and efforts of Albrecht von Haller (1708-1777), of Berne, who is perhaps as worthy of the title "The Great" as any philosopher who has been so christened by his contemporaries since the time of Hippocrates. Celebrated as a physician, he was proficient in various fields, being equally famed in his own time as poet, botanist, and statesman, and dividing his attention between art and science.
As a child Haller was so sickly that he was unable to amuse himself with the sports and games common to boys of his age, and so passed most of his time poring over books. When ten years of age he began writing poems in Latin and German, and at fifteen entered the University of Tubingen. At seventeen he wrote learned articles in opposition to certain accepted doctrines, and at nineteen he received his degree of doctor. Soon after this he visited England, where his zeal in dissecting brought him under suspicion of grave-robbery, which suspicion made it expedient for him to return to the Continent. After studying botany in Basel for some time he made an extended botanical journey through Switzerland, finally settling in his native city, Berne, as a practising physician. During this time he did not neglect either poetry or botany, publishing anonymously a collection of poems.
In 1736 he was called to Gottingen as professor of anatomy, surgery, chemistry, and botany. During his labors in the university he never neglected his literary work, sometimes living and sleeping for days and nights together in his library, eating his meals while delving in his books, and sleeping only when actually compelled to do so by fatigue. During all this time he was in correspondence with savants from all over the world, and it is said of him that he never left a letter of any kind unanswered.
Haller's greatest contribution to medical science was his famous doctrine of irritability, which has given him the name of "father of modern nervous physiology," just as Harvey is called "the father of the modern physiology of the blood." It has been said of this famous doctrine of irritability that "it moved all the minds of the century--and not in the departments of medicine alone--in a way of which we of the present day have no satisfactory conception, unless we compare it with our modern Darwinism."[1]
The principle of general irritability had been laid down by Francis Glisson (1597-1677) from deductive studies, but Haller proved by experiments along the line of inductive methods that this irritability was not common to all "fibre as well as to the fluids of the body," but something entirely special, and peculiar only to muscular substance. He distinguished between irritability of muscles and sensibility of nerves. In 1747 he gave as the three forces that produce muscular movements: elasticity, or "dead nervous force"; irritability, or "innate nervous force"; and nervous force in itself. And in 1752 he described one hundred and ninety experiments for determining what parts of the body possess "irritability"--that is, the property of contracting when stimulated. His conclusion that this irritability exists in muscular substance alone and is quite independent of the nerves proceeding to it aroused a controversy that was never definitely settled until late in the nineteenth century, when Haller's theory was found to be entirely correct.
It was in pursuit of experiments to establish his theory of irritability that Haller made his chief discoveries in embryology and development. He proved that in the process of incubation of the egg the first trace of the heart of the chick shows itself in the thirty-eighth hour, and that the first trace of red blood showed in the forty-first hour. By his investigations upon the lower animals he attempted to confirm the theory that since the creation of genus every individual is derived from a preceding individual--the existing theory of preformation, in which he believed, and which taught that "every individual is fully and completely preformed in the germ, simply growing from microscopic to visible proportions, without developing any new parts."
In physiology, besides his studies of the nervous system, Haller studied the mechanism of respiration, refuting the teachings of Hamberger (1697-1755), who maintained that the lungs contract independently. Haller, however, in common with his contemporaries, failed utterly to understand the true function of the lungs. The great physiologist's influence upon practical medicine, while most profound, was largely indirect. He was a theoretical rather than a practical physician, yet he is credited with being the first physician to use the watch in counting the pulse.
Battista Morgagni
A great contemporary of Haller was Giovanni Battista Morgagni (1682-1771), who pursued what Sydenham had neglected, the investigation in anatomy, thus supplying a necessary counterpart to the great Englishman's work. Morgagni's investigations were directed chiefly to the study of morbid anatomy--the study of the structure of diseased tissue, both during life and post mortem, in contrast to the normal anatomical structures. This work cannot be said to have originated with him; for as early as 1679 Bonnet had made similar, although less extensive, studies; and later many investigators, such as Lancisi and Haller, had made post-mortem studies. But Morgagni's De sedibus et causis morborum per anatomen indagatis was the largest, most accurate, and best-illustrated collection of cases that had ever been brought together, and marks an epoch in medical science. From the time of the publication of Morgagni's researches, morbid anatomy became a recognized branch of the medical science, and the effect of the impetus thus given it has been steadily increasing since that time.
William Hunter
William Hunter (1718-1783) must always be remembered as one of the greatest physicians and anatomists of the eighteenth century, and particularly as the first great teacher of anatomy in England; but his fame has been somewhat overshadowed by that of his younger brother John.
Hunter had been intended and educated for the Church, but on the advice of the surgeon William Cullen he turned his attention to the study of medicine. His first attempt at teaching was in 1746, when he delivered a series of lectures on surgery for the Society of Naval Practitioners. These lectures proved so interesting and instructive that he was at once invited to give others, and his reputation as a lecturer was soon established. He was a natural orator and story-teller, and he combined with these attractive qualities that of thoroughness and clearness in demonstrations, and although his lectures were two hours long he made them so full of interest that his pupils seldom tired of listening. He believed that he could do greater good to the world by "publicly teaching his art than by practising it," and even during the last few days of his life, when he was so weak that his friends remonstrated against it, he continued his teaching, fainting from exhaustion at the end of his last lecture, which preceded his death by only a few days.
For many years it was Hunter's ambition to establish a museum where the study of anatomy, surgery, and medicine might be advanced, and in 1765 he asked for a grant of a plot of ground for this purpose, offering to spend seven thousand pounds on its, erection besides endowing it with a professorship of anatomy. Not being able to obtain this grant, however, he built a house, in which were lecture and dissecting rooms, and his museum. In this museum were anatomical preparations, coins, minerals, and natural-history specimens.
Hunter's weakness was his love of controversy and his resentment of contradiction. This brought him into strained relations with many of the leading physicians of his time, notably his own brother John, who himself was probably not entirely free from blame in the matter. Hunter is said to have excused his own irritability on the grounds that being an anatomist, and accustomed to "the passive submission of dead bodies," contradictions became the more unbearable. Many of the physiological researches begun by him were carried on and perfected by his more famous brother, particularly his investigations of the capillaries, but he added much to the anatomical knowledge of several structures of the body, notably as to the structure of cartilages and joints.
| Meyer - The Hunters in Embryology (1936-7) |
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Part I | Part 2 | Part 3 | Arthur Meyer | Historic Embryology Papers |
John Hunter
In Abbot Islip's chapel in Westminster Abbey, close to the resting-place of Ben Jonson, rest the remains of John Hunter (1728-1793), famous in the annals of medicine as among the greatest physiologists and surgeons that the world has ever produced: a man whose discoveries and inventions are counted by scores, and whose field of research was only limited by the outermost boundaries of eighteenth-century science, although his efforts were directed chiefly along the lines of his profession.
Until about twenty years of age young Hunter had shown little aptitude for study, being unusually fond of out-door sports and amusements; but about that time, realizing that some occupation must be selected, he asked permission of his brother William to attempt some dissections in his anatomical school in London. To the surprise of his brother he made this dissection unusually well; and being given a second, he acquitted himself with such skill that his brother at once predicted that he would become a great anatomist. Up to this time he had had no training of any kind to prepare him for his professional career, and knew little of Greek or Latin--languages entirely unnecessary for him, as he proved in all of his life work. Ottley tells the story that, when twitted with this lack of knowledge of the "dead languages" in after life, he said of his opponent, "I could teach him that on the dead body which he never knew in any language, dead or living."
By his second year in dissection he had become so skilful that he was given charge of some of the classes in his brother's school; in 1754 he became a surgeon's pupil in St. George's Hospital, and two years later house-surgeon. Having by overwork brought on symptoms that seemed to threaten consumption, he accepted the position of staff-surgeon to an expedition to Belleisle in 1760, and two years later was serving with the English army at Portugal. During all this time he was constantly engaged in scientific researches, many of which, such as his observations of gun-shot wounds, he put to excellent use in later life. On returning to England much improved in health in 1763, he entered at once upon his career as a London surgeon, and from that time forward his progress was a practically uninterrupted series of successes in his profession.
Hunter's work on the study of the lymphatics was of great service to the medical profession. This important net-work of minute vessels distributed throughout the body had recently been made the object of much study, and various students, including Haller, had made extensive investigations since their discovery by Asellius. But Hunter, in 1758, was the first to discover the lymphatics in the neck of birds, although it was his brother William who advanced the theory that the function of these vessels was that of absorbents. One of John Hunter's pupils, William Hewson (1739-1774), first gave an account, in 1768, of the lymphatics in reptiles and fishes, and added to his teacher's investigations of the lymphatics in birds. These studies of the lymphatics have been regarded, perhaps with justice, as Hunter's most valuable contributions to practical medicine.
In 1767 he met with an accident by which he suffered a rupture of the tendo Achillis--the large tendon that forms the attachment of the muscles of the calf to the heel. From observations of this accident, and subsequent experiments upon dogs, he laid the foundation for the now simple and effective operation for the cure of club feet and other deformities involving the tendons. In 1772 he moved into his residence at Earlscourt, Brompton, where he gathered about him a great menagerie of animals, birds, reptiles, insects, and fishes, which he used in his physiological and surgical experiments. Here he performed a countless number of experiments--more, probably, than "any man engaged in professional practice has ever conducted." These experiments varied in nature from observations of the habits of bees and wasps to major surgical operations performed upon hedgehogs, dogs, leopards, etc. It is said that for fifteen years he kept a flock of geese for the sole purpose of studying the process of development in eggs.
Hunter began his first course of lectures in 1772, being forced to do this because he had been so repeatedly misquoted, and because he felt that he could better gauge his own knowledge in this way. Lecturing was a sore trial to him, as he was extremely diffident, and without writing out his lectures in advance he was scarcely able to speak at all. In this he presented a marked contrast to his brother William, who was a fluent and brilliant speaker. Hunter's lectures were at best simple readings of the facts as he had written them, the diffident teacher seldom raising his eyes from his manuscript and rarely stopping until his complete lecture had been read through. His lectures were, therefore, instructive rather than interesting, as he used infinite care in preparing them; but appearing before his classes was so dreaded by him that he is said to have been in the habit of taking a half-drachm of laudanum before each lecture to nerve him for the ordeal. One is led to wonder by what name he shall designate that quality of mind that renders a bold and fearless surgeon like Hunter, who is undaunted in the face of hazardous and dangerous operations, a stumbling, halting, and "frightened" speaker before a little band of, at most, thirty young medical students. And yet this same thing is not unfrequently seen among the boldest surgeons.
Hunter's Operation for the Cure of Aneurisms
It should be an object-lesson to those who, ignorantly or otherwise, preach against the painless vivisection as practised to-day, that by the sacrifice of a single deer in the cause of science Hunter discovered a fact in physiology that has been the means of saving thousands of human lives and thousands of human bodies from needless mutilation. We refer to the discovery of the "collateral circulation" of the blood, which led, among other things, to Hunter's successful operation upon aneurisms.
Simply stated, every organ or muscle of the body is supplied by one large artery, whose main trunk distributes the blood into its lesser branches, and thence through the capillaries. Cutting off this main artery, it would seem, should cut off entirely the blood-supply to the particular organ which is supplied by this vessel; and until the time of Hunter's demonstration this belief was held by most physiologists. But nature has made a provision for this possible stoppage of blood-supply from a single source, and has so arranged that some of the small arterial branches coming from the main supply-trunk are connected with other arterial branches coming from some other supply-trunk. Under normal conditions the main arterial trunks supply their respective organs, the little connecting arterioles playing an insignificant part. But let the main supply-trunk be cut off or stopped for whatever reason, and a remarkable thing takes place. The little connecting branches begin at once to enlarge and draw blood from the neighboring uninjured supply-trunk, This enlargement continues until at last a new route for the circulation has been established, the organ no longer depending on the now defunct original arterial trunk, but getting on as well as before by this "collateral" circulation that has been established.
The thorough understanding of this collateral circulation is one of the most important steps in surgery, for until it was discovered amputations were thought necessary in such cases as those involving the artery supplying a leg or arm, since it was supposed that, the artery being stopped, death of the limb and the subsequent necessity for amputation were sure to follow. Hunter solved this problem by a single operation upon a deer, and his practicality as a surgeon led him soon after to apply this knowledge to a certain class of surgical cases in a most revolutionary and satisfactory manner.
What led to Hunter's far-reaching discovery was his investigation as to the cause of the growth of the antlers of the deer. Wishing to ascertain just what part the blood-supply on the opposite sides of the neck played in the process of development, or, perhaps more correctly, to see what effect cutting off the main blood-supply would have, Hunter had one of the deer of Richmond Park caught and tied, while he placed a ligature around one of the carotid arteries--one of the two principal arteries that supply the head with blood. He observed that shortly after this the antler (which was only half grown and consequently very vascular) on the side of the obliterated artery became cold to the touch--from the lack of warmth-giving blood. There was nothing unexpected in this, and Hunter thought nothing of it until a few days later, when he found, to his surprise, that the antler had become as warm as its fellow, and was apparently increasing in size. Puzzled as to how this could be, and suspecting that in some way his ligature around the artery had not been effective, he ordered the deer killed, and on examination was astonished to find that while his ligature had completely shut off the blood-supply from the source of that carotid artery, the smaller arteries had become enlarged so as to supply the antler with blood as well as ever, only by a different route.
Hunter soon had a chance to make a practical application of the knowledge thus acquired. This was a case of popliteal aneurism, operations for which had heretofore proved pretty uniformly fatal. An aneurism, as is generally understood, is an enlargement of a certain part of an artery, this enlargement sometimes becoming of enormous size, full of palpitating blood, and likely to rupture with fatal results at any time. If by any means the blood can be allowed to remain quiet for even a few hours in this aneurism it will form a clot, contract, and finally be absorbed and disappear without any evil results. The problem of keeping the blood quiet, with the heart continually driving it through the vessel, is not a simple one, and in Hunter's time was considered so insurmountable that some surgeons advocated amputation of any member having an aneurism, while others cut down upon the tumor itself and attempted to tie off the artery above and below. The first of these operations maimed the patient for life, while the second was likely to prove fatal.
In pondering over what he had learned about collateral circulation and the time required for it to become fully established, Hunter conceived the idea that if the blood-supply was cut off from above the aneurism, thus temporarily preventing the ceaseless pulsations from the heart, this blood would coagulate and form a clot before the collateral circulation could become established or could affect it. The patient upon whom he performed his now celebrated operation was afflicted with a popliteal aneurism--that is, the aneurism was located on the large popliteal artery just behind the knee-joint. Hunter, therefore, tied off the femoral, or main supplying artery in the thigh, a little distance above the aneurism. The operation was entirely successful, and in six weeks' time the patient was able to leave the hospital, and with two sound limbs. Naturally the simplicity and success of this operation aroused the attention of Europe, and, alone, would have made the name of Hunter immortal in the annals of surgery. The operation has ever since been called the "Hunterian" operation for aneurism, but there is reason to believe that Dominique Anel (born about 1679) performed a somewhat similar operation several years earlier. It is probable, however, that Hunter had never heard of this work of Anel, and that his operation was the outcome of his own independent reasoning from the facts he had learned about collateral circulation. Furthermore, Hunter's mode of operation was a much better one than Anel's, and, while Anel's must claim priority, the credit of making it widely known will always be Hunter's.
The great services of Hunter were recognized both at home and abroad, and honors and positions of honor and responsibility were given him. In 1776 he was appointed surgeon-extraordinary to the king; in 1783 he was elected a member of the Royal Society of Medicine and of the Royal Academy of Surgery at Paris; in 1786 he became deputy surgeon-general of the army; and in 1790 he was appointed surgeon-general and inspector-general of hospitals. All these positions he filled with credit, and he was actively engaged in his tireless pursuit of knowledge and in discharging his many duties when in October, 1793, he was stricken while addressing some colleagues, and fell dead in the arms of a fellow-physician.
| Meyer - The Hunters in Embryology (1936-7) |
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Part I | Part 2 | Part 3 | Arthur Meyer | Historic Embryology Papers |
Lazzaro Spallanzani
Hunter's great rival among contemporary physiologists was the Italian Lazzaro Spallanzani (1729-1799), one of the most picturesque figures in the history of science. He was not educated either as a scientist or physician, devoting, himself at first to philosophy and the languages, afterwards studying law, and later taking orders. But he was a keen observer of nature and of a questioning and investigating mind, so that he is remembered now chiefly for his discoveries and investigations in the biological sciences. One important demonstration was his controversion of the theory of abiogenesis, or "spontaneous generation," as propounded by Needham and Buffon. At the time of Needham's experiments it had long been observed that when animal or vegetable matter had lain in water for a little time--long enough for it to begin to undergo decomposition--the water became filled with microscopic creatures, the "infusoria animalculis." This would tend to show, either that the water or the animal or vegetable substance contained the "germs" of these minute organisms, or else that they were generated spontaneously. It was known that boiling killed these animalcules, and Needham agreed, therefore, that if he first heated the meat or vegetables, and also the water containing them, and then placed them in hermetically scaled jars--if he did this, and still the animalcules made their appearance, it would be proof-positive that they had been generated spontaneously. Accordingly be made numerous experiments, always with the same results--that after a few days the water was found to swarm with the microscopic creatures. The thing seemed proven beyond question--providing, of course, that there had been no slips in the experiments.
But Abbe Spallanzani thought that he detected such slips in Needham's experiment. The possibility of such slips might come in several ways: the contents of the jar might not have been boiled for a sufficient length of time to kill all the germs, or the air might not have been excluded completely by the sealing process. To cover both these contingencies, Spallanzani first hermetically sealed the glass vessels and then boiled them for three-quarters of an hour. Under these circumstances no animalcules ever made their appearance--a conclusive demonstration that rendered Needham's grounds for his theory at once untenable.[2]
Allied to these studies of spontaneous generation were Spallanzani's experiments and observations on the physiological processes of generation among higher animals. He experimented with frogs, tortoises, and dogs; and settled beyond question the function of the ovum and spermatozoon. Unfortunately he misinterpreted the part played by the spermatozoa in believing that their surrounding fluid was equally active in the fertilizing process, and it was not until some forty years later (1824) that Dumas corrected this error.
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18th Century Anatomy and Physiology Part 2
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العربية | català | 中文 | 中國傳統的 | français | Deutsche | עִברִית | हिंदी | bahasa Indonesia | italiano | 日本語 | 한국어 | မြန်မာ | Pilipino | Polskie | português | ਪੰਜਾਬੀ ਦੇ | Română | русский | Español | Swahili | Svensk | ไทย | Türkçe | اردو | ייִדיש | Tiếng Việt These external translations are automated and may not be accurate. (More? About Translations) |
Williams HS. A History of Science. (1904) Harper and Bros. New York.
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Cite this page: Hill, M.A. (2024, April 18) Embryology Book - A History of Science 8. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Book_-_A_History_of_Science_8
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