(a) The theory of Evolution, which makes the embryo pre-existent in the germ, and only rendered visible by the unfolding and expansion of its organs.(b) The theory of Epigenesis, which makes the embryo arise, by a series of successive differentiations, from a simple homogeneous mass into a complex heterogeneous organism.
(a) The theory of Evolution, which makes the embryo pre-existent in the germ, and only rendered visible by the unfolding and expansion of its organs.
(b) The theory of Epigenesis, which makes the embryo arise, by a series of successive differentiations, from a simple homogeneous mass into a complex heterogeneous organism.
The above quotation will show how closely Aristotle held to the theory of Epigenesis; and in another place he says, "Not at once is the animal a man or a horse, for the end is last attained; and the specific form is the end of each development."
Spontaneous generation is nowadays rejected by science; but Aristotle went so far as to believe that insects, molluscs, and even eels, were spontaneously generated. It is, however, noteworthy, in view of modern investigations, that he looked uponputrefyingmatter as the source of such development.
A chapter of this work is devoted to the consideration of the hereditary transmission of peculiarities from parent to offspring.
The fifth and last book contains inquiries into the cause of variation in the colour of the eyes and hair, the abundance of hair, the sleep of the embryo, sight and hearing, voice and the teeth.
Widely different opinions have been held from time to time of the value of Aristotle's biological labours. This philosopher's reputation has, perhaps, suffered most from those who have praised him most. The praise has often been of such an exaggerated character as to have become unmeaning, and to have carried with it the impression of insincerity on the part of the writer. Such are the laudations of Cuvier. To say as he does, "Alone, in fact, without predecessors, without having borrowed anything from the centuries which had gone before, since they had produced nothing enduring, the disciple of Plato discovered and demonstrated more truths and executed more scientific labours in a life of sixty-two years than twenty centuries after him were able to do," is of course to talk nonsense, for the method which Aristotle applied was that which Hippocrates had used so well before him; and it is evident to any one that both his predecessors and contemporaries are frequently laid under contribution by Aristotle, although the authority is rarely, if ever, stated by him unless heis about to refute the view put forward. Exaggerated praise of any author has a tendency to excite depreciation correspondingly unjust and untrue. It has been so in the case of this great man. In the endeavour to depose him from the impossible position to which his panegyrists had exalted him, his detractors have gone to any length. The principal charges brought against his biological work have been inaccuracy and hasty generalization. In support of the charge of inaccuracy, some of the extraordinary statements which are met with in his works are adduced. "These," Professor Huxley says, "are not so much to be called errors as stupidities." Some, however, of the inaccuracies alleged against Aristotle are fancied rather than real. Thus he is charged with having represented that the arteries contained nothing but air; that the aorta arose from the right ventricle; that the heart did not beat in any other animal but man; that reptiles had no blood, etc.; although in reality he made no one of these assertions. There remain, nevertheless, the gross misstatements referred to above, and which really do occur. Such, for instance, as that there is but a single bone in the neck of the lion; that there are more teeth in male than in female animals; that the mouth of the dolphin is placed on the under surface of the body; that the back of the skull is empty, etc. Although these absurdities undoubtedly occur in Aristotle's works, it by no meansfollows that he is responsible for them. Bearing in mind the curious history of the manuscripts of his treatises, we shall find it far more reasonable to conclude that such errors crept in during the process of correction and restoration, by men apparently ignorant of biology, than that (to take only one case) an observer who had distinguished the cetacea from fishes and had detected their hidden mammæ, discovered their lungs, and recognized the distinct character of their bones, should have been so blind as to fancy that the mouth of these animals was on the under surface of the body.
That Aristotle made hasty generalizations is true; but it was unavoidable. Biology was in so early a stage that a theory had often of necessity to be founded on a very slight basis of facts. Yet, notwithstanding this drawback, so great was the sagacity of this philosopher, that many of his generalizations, which he himself probably looked upon as temporary, have held their ground for twenty centuries, or, having been lost sight of, have been discovered and put forward as original by modern biologists. Thus "the advantage of physiological division of labour was first set forth," says Milne-Edwards, "by myself in 1827;" and yet Aristotle had said[13]that "whenever Nature is able to provide two separate instruments for two separate uses, without the one hampering the other, she does so, instead of actinglike a coppersmith, who for cheapness makes a spit-and-a-candlestick in one.[14]It is only when this is impossible that she uses one organ for several functions."
In conclusion, we may say that the great Stagirite expounded the true principles of science, and that when he failed his failure was caused by lack of materials. His desire for completeness, perhaps, tempted him at times to fill in gaps with such makeshifts as came to his hand; but no one knew better than he did that "theories must be abandoned unless their teachings tally with the indisputable results of observation."[15]
FOOTNOTES:[3]Pliny, "Natural History," viii. c. 16.[4]"History of Animals," i. 11.[5]Bk. iii. 19.[6]"Meteorology," iv. 7-11.[7]"History of Animals," i. 16.[8]"History of Animals," vi. 3.[9]"On some of the errors attributed to Aristotle."[10]"History of Animals," i. 17.[11]See Professor Huxley's article already referred to.[12]"Aristotle," by G. H. Lewes, p. 325.[13]"De Part. Anim.," iv. 6.[14]ὀβελισκολÏχνιον.[15]"De Gener.," iii. 10, quoted by Dr. Ogle.
[3]Pliny, "Natural History," viii. c. 16.
[3]Pliny, "Natural History," viii. c. 16.
[4]"History of Animals," i. 11.
[4]"History of Animals," i. 11.
[5]Bk. iii. 19.
[5]Bk. iii. 19.
[6]"Meteorology," iv. 7-11.
[6]"Meteorology," iv. 7-11.
[7]"History of Animals," i. 16.
[7]"History of Animals," i. 16.
[8]"History of Animals," vi. 3.
[8]"History of Animals," vi. 3.
[9]"On some of the errors attributed to Aristotle."
[9]"On some of the errors attributed to Aristotle."
[10]"History of Animals," i. 17.
[10]"History of Animals," i. 17.
[11]See Professor Huxley's article already referred to.
[11]See Professor Huxley's article already referred to.
[12]"Aristotle," by G. H. Lewes, p. 325.
[12]"Aristotle," by G. H. Lewes, p. 325.
[13]"De Part. Anim.," iv. 6.
[13]"De Part. Anim.," iv. 6.
[14]ὀβελισκολÏχνιον.
[14]ὀβελισκολÏχνιον.
[15]"De Gener.," iii. 10, quoted by Dr. Ogle.
[15]"De Gener.," iii. 10, quoted by Dr. Ogle.
Underthe Ptolemies a powerful stimulus was given to biological studies at Alexandria. Scientific knowledge was carried a step or two beyond the limit reached by Aristotle. Thus Erasistratus and Herophilus thoroughly investigated the structure and functions of the valves of the heart, and were the first to recognize the nerves as organs of sensation. But, unfortunately, no complete record of the interesting work carried on by these men has come down to our times. The first writer after Aristotle whose works arrest attention is Caius Plinius Secundus, whose so-called "Natural History," in thirty-seven volumes, remains to the present day as a monument of industrious compilation. But, as a biologist properly so called, Pliny is absolutely without rank, for he lacked that practical acquaintance with the subject which alone could enable him to speak with authority. Of information he had an almost inexhaustible store; of actual knowledge, the result of observation and experience, so far as biological studies were concerned, he had butlittle. This was largely due to the encyclopædic character of the work he undertook; his mental powers were weighed down by an enormous mass of unarranged and ill-digested materials. But it was due also to the peculiar bent of Pliny's mind. He was not, like Aristotle, an original thinker; he was essentially a student of books, an immensely industrious but not always judicious compiler. Often his selections from other works prove that he failed to appreciate the relative importance of the different subjects to which he made reference. His knowledge of the Greek language appears, too, to have been defective, for he gives at times the wrong Latin names to objects described by his Greek authorities. To these defects must be added his marvellous readiness to believe any statement, provided only that it was uncommon; while, on the other hand, he showed an indefensible scepticism in regard to what was really deserving of attention. The chief value of his work consists in the historical and chronological notes of the progress of some of the subjects of which he treats—fragments of writings which would otherwise be lost to us. Pliny was killed in the destruction of Pompeii,A.D.79.
Claudius Galenus was born at Pergamus, in Asia Minor, in the hundred and thirty-first year of the Christian era. Few writers ever exercised for so long a time such an undisputed sway over the opinions of mankind as didthis wonderful man. His authority was estimated at a much higher rate than that of all the biological writers combined who flourished during a period of more than twelve centuries, and it was often considered a sufficient argument against a hypothesis, or even an alleged matter of fact, that it was contrary to Galen.
Endowed by nature with a penetrating genius and a mind of restless energy, he was eminently qualified to profit by a comprehensive and liberal education. And such he received. His father, Nicon, an architect, was a man of learning and ability—a distinguished mathematician and an astronomer—and seems to have devoted much time and care to the education of his son. The youth appears to have studied philosophy successively in the schools of the Stoics, Academics, Peripatetics, and Epicureans, without attaching himself exclusively to any one of these, and to have taken from each what he thought to be the most essential parts of their system, rejecting, however, altogether the tenets of the Epicureans. At the age of twenty-one, on the death of his father, he went to Smyrna to continue the study of medicine, to which he had now devoted himself. After leaving this place and having travelled extensively, he took up his residence at Alexandria, which was then the most favourable spot for the pursuit of medical studies. Here he is said to have remained until he was twenty-eight years of age, when his reputation securedhis appointment, in his native city of Pergamus, to the office of physician in charge of the athletes in the gymnasia situated within the precincts of the temple of Æsculapius. For five or six years he lived in Pergamus, and then a revolt compelled him to leave his native town. The advantages offered by Rome led him to remove thither and take up his residence in the capital of the world. Here his skill, sagacity, and knowledge soon brought him into notice, and excited the jealousy of the Roman doctors, which was still further increased by some wonderful cures the young Greek physician succeeded in effecting. Possibly it was owing to the ill feeling shown to Galen that, on the outbreak of an epidemic a year afterwards, he left the imperial city and proceeded to Brindisi, and embarked for Greece. It was his intention to devote his time to the study of natural history, and for this purpose he visited Cyprus, Palestine, and Lemnos. While at the last-named place, however, he was suddenly summoned to Aquileia to meet the Emperors Marcus Aurelius and Lucius Verus. He travelled through Thrace and Macedonia on foot, met the imperial personages, and prepared for them a medicine, for which he seems to have been famous, and which is spoken of as thetheriac. It was probably some combination of opium with various aromatics and stimulants, for antidotes of many different kinds were habitually taken by the Romans to preserve them fromthe ill effects of poison and of the bites of venomous animals.[16]
With the Emperor M. Aurelius he returned to Rome, and became afterwards doctor to the young Emperor Commodus. He did not, however, remain for a long period at Rome, and probably passed the greater part of the rest of his life in his native country.
Although the date of his death is not positively known, yet it appears from a passage[17]in his writings that he was living in the reign of Septimius Severus; and Suidas seems to have reason for asserting that he reached his seventieth year.
Galen's writings represent the common depository of the anatomical knowledge of the day; what he had learnt from many teachers, rather than the results of his own personal research. Roughly speaking, they deal with the following subjects: Anatomy and Physiology, Dietetics and Hygiene, Pathology, Diagnosis and Semeiology, Pharmacy and Materia Medica, Therapeutics.
The only works of this voluminous writer at which we can here glance are those dealing with Anatomy and Physiology. These exhibit numerous illustrations of Galen's familiarity with practical anatomy, although it was most likely comparative rather than humananatomy at which he especially worked. Indeed, he seems to have had but few opportunities of carrying on human dissections, for he thinks himself happy in having been able to examine at Alexandria two human skeletons; and he recommends the dissection of monkeys because of their exact resemblance to man. To this disadvantage may, perhaps, be attributed the readiness, which sometimes appears, to assume identity of organization between man and the brutes. Thus, because in certain animals he found a double biliary duct, he concluded the same to be the case in man, and in one instance he proceeded to deduce the cause of disease from this erroneous assumption.
He supposed that there were three modes of existence in man, namely—
(a) The nutritive, which was common to all animals and plants, of which the liver was the source.(b) The vital, of which the heart was the source.(c) The rational, of which the brain was the source.
(a) The nutritive, which was common to all animals and plants, of which the liver was the source.
(b) The vital, of which the heart was the source.
(c) The rational, of which the brain was the source.
Again, he considered that the animal economy possessed four natural powers—
(1) The attractive.(2) The alterative or assimilative.(3) The retentive or digestive.(4) The expulsive.
(1) The attractive.
(2) The alterative or assimilative.
(3) The retentive or digestive.
(4) The expulsive.
Like his predecessors, he asserted that there were four humours, namely, blood, yellow bile, black bile, andaqueous serum. He held that it was the office of the liver to complete the process of sanguification commenced in the stomach, and that during this process the yellow bile was attracted by the branches of the hepatic duct and gall-bladder; the black bile being attracted by the spleen, and the aqueous humour by the two kidneys; while the liver itself retained the pure blood, which was afterwards attracted by the heart through the vena cava, by whose ramifications it was distributed to the various parts of the body.
Following Aristotle especially, he regarded hair, nails, arteries, veins, cartilage, bone, ligament, membranes, glands, fat, and muscle as the simplest constituents of the body, formed immediately from the blood, and perfectly homogeneous in character. The organic members,e.g.lungs, liver, etc., he looked upon as formed of several of the foregoing simple parts.
The osteology contained in Galen's works is nearly as perfect as that of the present day. He correctly names and describes the bones and sutures of the cranium; notices the quadrilateral shape of the parietals, the peculiar situation and shape of the sphenoid, and the form and character of the ethmoid, malar, maxillary, and nasal bones. He divides the vertebral columns into cervical, dorsal, and lumbar portions.
With regard to the nervous system, he taught that the nerves of the senses are distinct from those whichimpart the power of motion to muscles—that the former are derived from the anterior parts of the brain, while the latter arise from the posterior portion, or from the spinal cord. He maintained that the nerves of the finer senses are formed of matter too soft to be the vehicles of muscular motion; whereas, on the other hand, the nerves of motion are too hard to be susceptible of fine sensibility. His description of the method of demonstrating the different parts of the brain by dissection is very interesting, and, like his references to various instruments and contrivances, proves him to have been a practical and experienced anatomist.
In his description of the organs and process of nutrition, absorption by the veins of the stomach is correctly noticed, and the union of the mesenteric veins into one commonvena portæis pointed out. The communications between the ramifications of the vena portæ and of the proper veins of the liver are supposed by Galen to be effected by means of anastomosing pores or channels. Although it is evident that Galen was ignorant of the true absorbent system, yet he appears to have been aware of thelacteals; for he says that in addition to those mesenteric veins which by their union form the vena portæ, there are visible in every part of the mesentery other veins, proceeding also from the intestines, which terminate in glands; and he supposes that these veins are intended for the nourishment of theintestines themselves. Some of Galen's contemporaries asserted that upon exposing the mesentery of a sucking animal several small vessels were seen filledfirstwith air, andafterwardswith milk. They had, doubtless, mistaken colourless lymph for air; but Galen ridicules both assertions, and thereby shows that he had not examined the contents of the lacteals. This is somewhat remarkable, because as a rule he omitted no opportunity of determining with certainty, by vivisection and experiments on living animals, the uses of the various parts of the body. As an illustration of this, we have his correct statement, established by experiment, that the pylorus acts as a valveonlyduring the process of digestion, and that it is relaxed when digestion is completed.
He recognizes that the flesh of the heart is somewhat different to that of the muscles of voluntary motion. Its fibres are described as being arranged in longitudinal and transverse bundles; the former by their contractions shortening the organ, the latter compressing and narrowing it. Such statements show that he regarded the heart as essentially muscular. He thought, however, that it was entirely destitute of nerves. Although he admitted that possibly it had one small branch derived from thenervus vagussent to it, yet he entirely overlooked the great nervous plexus surrounding the roots of the blood-vessels, from which branches proceed in company withthe branches of the coronary arteries and veins, and penetrate the muscular substance of the ventricles. He endeavoured to prove, by experiment, observation, and reasoning, that the arteries as well as the veins contained blood, and in this connection he tells an amusing story. A certain teacher of anatomy, who had declared that the aorta contained no blood, was earnestly desired by his pupils, who were ardent disciples of Galen, to exhibit the requisite demonstration, they themselves offering animals for the experiment. He, however, after various subterfuges, declined, until they promised to give him a suitable remuneration, which they raised by subscription among themselves to the amount of a thousand drachmæ (perhaps £30). The professor, being thus compelled to commence the experiment, totally failed in his attempt to cut down upon the aorta, to the no small amusement of his pupils, who, thereupon taking up the experiment themselves, made an opening into the thorax in the way in which they had been instructed by Galen, passed one ligature round the aorta at the part where it attaches itself to the spine, and another at its origin, and then, by opening the intervening portion of the artery, showed that blood was contained in it.
The arteries, Galen thought, possessed a pulsative and attractive power of their own, independently of the heart, the moment of their dilatation being the moment of their activity. They, in fact,drewtheir charge from the heart,as the heart by its diastoledrewits charge from the vena cava and the pulmonary vein. The pulse of the arteries, he also thought, was propagated by their coats, not by the wave of blood thrown into them by the heart. He taught that at every systole of the arteries a certain portion of their contents was discharged at their extremities, namely, by the exhalents and secretory vessels. Though he demonstrated the anastomosis of arteries and veins, he nowhere hints his belief that the contents of the former pass into the latter, to be conveyed back to the heart, and from it to be again diffused over the body. He made a near approach to the Harveian theory of the circulation, as Harvey himself admits in his "De Motu Cordis;"[18]but the grand point of difference between Galen and Harvey is the question whether or not, at every systole of the left ventricle, more blood is thrown out than is expended on exhalation, secretion, and nutrition. Upon this point Galen held the negative, and Harvey, as we all know, the affirmative.
The famous Asclepiads held that respiration was for the generation of the soul itself, breath and life being thus considered to be identical. Hippocrates thought it was for the nutrition and refrigeration of the innateheat, Aristotle for its ventilation, Erasistratus for the filling of the arteries with spirits. All these opinions are discussed and commented upon by Galen, who determines the purposes of respiration to be (1) to preserve the animal heat; (2) to evacuate from the blood the products of combustion.
He conjectured that there was in atmospheric air not only a quality friendly to the vital spirit, but also a quality inimical to it, which conjecture he drew from observation of the various phenomena accompanying the support and the extinction of flame; and he says that if we could find out why flame is extinguished by absence of the air, we might then know the nature of that substance which imparts warmth to the blood during the process of respiration.
On another occasion he says that it is evidently thequalityand not thequantityof the air which is necessary to life. He further shows that he recognized the analogy between respiration and combustion, by comparing the lungs to a lamp, the heart to its wick, the blood to the oil, and the animal heat to the flame.
From certain observations in various parts of his works, it appears that, although ignorant of the doctrine of atmospheric pressure, he was acquainted with some of its practical effects. Thus, he says, if you put one end of an open tube under water and suck out the air with the other end, you will draw up water into themouth, and that it is in this way that infants extract the milk from the mother's breast.
Again, Erasistratus supposed that the vapour of charcoal and of certain pits and wells was fatal to life becauselighterthan common air, but Galen maintained it to beheavier.
He describes two kinds of respiration, one by the mouths of the arteries of the lungs, and one by the mouths of the arteries of the skin. In each case, he says, the surrounding air is drawn into the vessels during their diastole, for the purpose of cooling the blood, and during their systole the fuliginous particles derived from the blood and other fluids of the body are forced out.
He considers the diaphragm to be the principal muscle of respiration, but he makes a clear distinction between ordinary respiration, which he calls a natural and involuntary effort, and that deliberate and forced respiration which is obedient to the will; and he says that there are different muscles for the two purposes. Elsewhere he particularly points out the two sets of intercostal muscles and their mode of action, of which, before his time, he asserts that anatomists were ignorant.
He describes various effects produced on respiration and on the voice by the division of those nerves which are connected with the thorax; and shows particularly the effect of dividing the recurrent branch of his sixth pair of cerebral nerves (the pneumogastric of modernanatomy). He explains how it happens that after division of the spinal cord, provided that division bebeneaththe lower termination of the neck, the diaphragm will still continue to act—in consequence, namely, of the origin of the phrenic nerve beingabovethe lower termination of the neck.
Before the time of Galen the medical profession was divided into several sects,e.g.Dogmatici, Empirici, Eclectici, Pneumatici, and Episynthetici, who were always disputing with one another. After his time all sects seem to have merged in his followers. The subsequent Greek and Roman biological writers were mere compilers from his works, and as soon as his writings were translated into Arabic they were at once adopted throughout the East to the exclusion of all others. He remained paramount throughout the civilized world until within the last three hundred years. In the records of the College of Physicians of England we read that Dr. Geynes was cited before the college in 1559 for impugning the infallibility of Galen, and was only admitted again into the privileges of his fellowship on acknowledgment of his error, and humble recantation signed with his own hand. Kurt Sprengel has well said that "if the physicians who remained so faithfully attached to Galen's system had inherited his penetrating mind, his observing glance, and his depth, the art of healing would have approached the limit of perfection before all theother sciences; but it was written in the book of destiny that mind and reason were to bend under the yoke of superstition and barbarism, and were only to emerge after centuries of lethargic sleep."
FOOTNOTES:[16]Hence the nameθηÏίακαι.[17]"De Antidotis," i. 13, vol. xiv. p. 65, Kuhn.[18]"Ex ipsius etiam Galeni verbis hanc veritatem confirmari posse, scilicet: non solum posse sanguinem e vena arteriosa in arteriam venosam et inde in sinistrum ventriculum cordis, et postea in arterias transmitti."—"De Motu Cordis," cap. vii.
[16]Hence the nameθηÏίακαι.
[16]Hence the nameθηÏίακαι.
[17]"De Antidotis," i. 13, vol. xiv. p. 65, Kuhn.
[17]"De Antidotis," i. 13, vol. xiv. p. 65, Kuhn.
[18]"Ex ipsius etiam Galeni verbis hanc veritatem confirmari posse, scilicet: non solum posse sanguinem e vena arteriosa in arteriam venosam et inde in sinistrum ventriculum cordis, et postea in arterias transmitti."—"De Motu Cordis," cap. vii.
[18]"Ex ipsius etiam Galeni verbis hanc veritatem confirmari posse, scilicet: non solum posse sanguinem e vena arteriosa in arteriam venosam et inde in sinistrum ventriculum cordis, et postea in arterias transmitti."—"De Motu Cordis," cap. vii.
Theauthority of Galen, at once a despotism and a religion, was scarcely ever called in question until the sixteenth century. No attempt worth recording was made during thirteen hundred years to extend the boundary of scientific knowledge in anatomy and physiology. It is true that the scholastic philosopher, Albertus Magnus, who was for a short time (1260-1262) Bishop of Ratisbon, in the middle of the thirteenth century wrote a "History of Animals," which was a remarkable production for the age in which he lived; although Sir Thomas Browne, in his famous "Enquiries into Common Errors," speaks of these "Tractates" as requiring to be received with caution, adding as regards Albertus that "he was a man who much advanced these opinions by the authoritie of his name, and delivered most conceits, with strickt enquirie into few."
As regards human anatomy, it was considered, during the Middle Ages, to be impiety to touch with a scalpel "the dead image of God," as man's body was called.Mundinus, the professor of medicine at Bologna from 1315 to 1318, was the first to attempt any such thing. He exhibited the public dissection of three bodies, but by this created so great a scandal that he gave up the practice, and contented himself with publishing a work, "De Anatome," which formed a sort of commentary on Galen. This work, with additions, continued to be the text-book of the schools until the time of Vesalius, who founded the study of anatomy as nowadays pursued.
Andreas Vesalius was born at Brussels, on the last day of the year 1514, of a family which for several generations had been eminent for medical attainments. He was sent as a boy to Louvain, where he spent the greater part of his leisure in researches into the mechanism of the lower animals. He was a born dissector, who, after careful examination, in his early days, of rats, moles, dogs, cats, monkeys, and the like, came, in after-life, to be dissatisfied with any less knowledge of the anatomy of man.
He acquired great proficiency in the scholarship of the day. Indeed the Latin, in which he afterwards wrote his great work, is so singularly pure that one of his detractors pretended that Vesalius must have got some good scholar to write the Latin for him. Latin was not the only language in which he was proficient; he added Greek and Arabic to his other accomplishments, and this for the purpose of reading the great biological works in the languages in which they were originally written. FromLouvain the youth went to Paris, where he studied anatomy under a most distinguished physician, Sylvius. It was the practice of that illustrious professor to read to his class Galen on the "Use of Parts," omitting nearly all the sections where exact knowledge of anatomical detail was necessary. Sometimes an attempt was made to illustrate the lecture by the dissection of a dog, but such illustration more often exposed the professor's ignorance than it added to the student's knowledge. Indirectly, however, it did good, for whenever Sylvius, after having tried in vain to demonstrate some muscle, or nerve, or vein, left the room, his pupil Vesalius slipped down to the table, dissected out the part with great neatness, and triumphantly called the professor's attention to it on his return.
Besides studying under Sylvius, Vesalius had for his teacher at Paris the famous Winter, of Andernach, who was physician to Francis I. This learned man, in a work published three years after this period, speaks of Vesalius as a youth of great promise. At the age of nineteen Vesalius returned to Louvain; and here for the first time he openly demonstrated from the human subject. In this connection a somewhat ghastly story is told, which serves to show the intensity of the enthusiasm with which our anatomist was inspired. On a certain evening it chanced that Vesalius, in company with a friend, had rambled out of the gates of Louvain to a spot where thebodies of executed criminals were wont to be exposed. A noted robber had been executed. His body had been chained to a stake and slowly roasted; and the birds had so entirely stripped the bones of every vestige of flesh, that a perfect skeleton, complete and clean, was suspended before the eyes of the anatomist, who had been striving hitherto to piece together such a thing out of the bones of many people, gathered as occasion offered. Mounting upon the shoulder of his friend, Vesalius ascended the charred stake and forcibly tore away the limbs, leaving only the trunk, which was securely bound by iron chains. With these stolen bones under their clothes the two youths returned to Louvain. In the night, however, and alone, the sturdy Vesalius found his way again to the place—which to most men, at any rate in those times, would have been associated with unspeakable horrors—and there, by sheer force, wrenched away the trunk, and buried it. Then leisurely and carefully, day after day, he smuggled through the city gates bone after bone. Afterwards, when he had set up the perfect skeleton in his own house, he did not hesitate to demonstrate from it. But such an act of daring plunder could not escape detection, and he was banished from Louvain for the offence. This story is here quoted only to show the extraordinary physical and moral courage which the anatomist possessed; which upheld him through toils, dangers, and disgusts; and by whichhe was strengthened to carry on, even in a cruel and superstitious age, and placed, as he was, on the very threshold of the Inquisition, a work at all times repulsive to flesh and blood.
After serving for a short time as a surgeon in the army of the Emperor Charles V., Vesalius went to Italy, where he at once attracted the attention of the most learned men, and became, at the age of twenty-two, Professor of Anatomy at the University of Padua. This was the first purely anatomical professorship that had been established out of the funds of any university. For seven years he held the office, and he was at the same time professor at Bologna and at Pisa. During these years his lectures were always well attended, for they were a striking innovation on the tameness of conventional routine. In each university the services of the professor were confined to a short course of demonstrations, so that his duties were complete when he had spent, during the winter, a few weeks at each of the three towns in succession. He then returned to Venice, which he appears to have made his head-quarters. At this city, as well as at Pisa, special facilities were offered to the professor for obtaining bodies either of condemned criminals or others. At Padua and Bologna the enthusiasm of the students, who became resurrectionists on their teacher's behalf, kept the lecture-table supplied with specimens. They were in the habit of watching allthe symptoms in men dying of a fatal malady, and noting where, after death, such men were buried. The seclusion of the graveyard was then invaded, and the corpse secretly conveyed by Andreas to his chamber, and concealed sometimes in his own bed. A diligent search was at once made to determine accurately the cause of death. This pitiless zeal for correct details in anatomy, associated as it was with indefatigable practice in physic, appeared to Vesalius, as it does to his successors of to-day, to be the only satisfactory method of acquiring that knowledge which is essential to a doctor. Thus it was that he, who at the age of twenty-two was able to name, with his eyes blindfolded, any human bone put into his hand, who was deeply versed in comparative anatomy, and had more accurate knowledge of the human frame than any graybeard of the time, enjoyed afterwards a reputation as a physician which was unbounded. One illustration of his sagacity in diagnosis will suffice. A patient of two famous court physicians at Madrid had a big and wonderful tumour on the loins. It would have been easily recognized in these days as an aneurismal tumour, but it greatly puzzled the two doctors. Vesalius was therefore consulted, and said, "There is a blood-vessel dilated; that tumour is full of blood." They were surprised at such a strange opinion; but the man died, the tumour was opened; blood was actually found in it, and we are toldin admirationem rapti fuère omnes.
It was not until after Vesalius had been three years professor that he began to distrust the infallibility of Galen's anatomical teaching. Constant practical experience in dissection, both human and comparative, slowly convinced him that—great anatomist as the "divus homo" had undoubtedly been—his statements were not only incomplete, but often wrong; further, that Galen very rarely wrote from actual inspection of the human subject, but based his teaching on a belief that the structure of a monkey was exactly similar to that of a man. With this conviction established, Vesalius proceeded to note with great care all the discrepancies between the text of Galen and the actual parts which it endeavoured to describe, and in this way a volume of considerable thickness was soon formed, consisting entirely of annotations upon Galen. The generally received authorities being thus found to be unreliable, it became necessary in the next place to collect and arrange the fundamental facts of anatomy upon a new and sounder basis. To this task Vesalius, at the age of twenty-five, devoted himself, and began his famous work on the "Fabric of the Human Body." Owing possibly to the good fortune of his family, and to the income which he derived from his professorships, Andreas was able to secure for his work the aid of some of the best artists of the day. To Jean Calcar, one of the ablest of the pupils of Titian, are due the splendid anatomical plates which illustratethe "Corporis Humani Fabrica," and which are incomparably better than those of any work which preceded it. To him most likely is due also the woodcut which adorns the first page, and which represents the young Vesalius, wearing professor's robes, standing at a lecture-table and pointing out, from a robust subject that lies before him, the inner secrets of the human body; while the tiers of benches that surround the professor are completely crowded with grave doctors struggling to see, even climbing upon the railings to do so.
But throughout the work the plates are used simply to illustrate and elucidate the text, and the information furnished in the latter is minute and accurate, and stated in well-polished Latin. As the author proceeds, he finds it necessary to disagree with Galen, and the reasons for this disagreement are given. The inevitable result follows that Vesalius is placed at issue not only with "the divine man," but also with all those who for thirteen centuries had unquestioningly followed him. Such a result Vesalius must have foreseen. It was not, therefore, a great surprise to him, perhaps, to receive, soon after the publication of his work, a violent onslaught from his old master Sylvius. He simply replied to it by a letter full of respect and friendly feeling, inquiring wherein he had been guilty of error. The answer he got was that he must show proper respect for Galen, if he wished to be regarded as a friend of Sylvius.
In 1546, three years after the publication of his great work, Andreas was summoned to Ratisbon to exercise his skill upon the emperor, and from that date he was ranked among the court physicians. In the same year, 1546, in a long letter, entitled "De usu Radicis Chinæ," he not only treats of the medicine by which the emperor's health had been restored, but he vindicates his teaching against his assailants, and again gives cumulative proof of the fact that Galen had dissected only brutes.
It was the practice of Vesalius, while he was professor in Italy, to issue a public notice the day before each demonstration, stating the time at which it would take place, and inviting all who decried his errors to attend and make their own dissections from his subject, and confound him openly. It does not appear that any one was rash enough ever to accept the challenge; yet, although the majority of the young men were on the side of Vesalius, the older teachers continued to regard him as a heretic, and in 1551 Sylvius published a bitterly personal attack. It was nothing to him that the results of actual dissection were against him—he even went so far as to assert that the men of his time were constructed somewhat differently to those of the time of Galen! Thus, to the proof that Vesalius gave that the carpal bones were not absolutely without marrow, as Galen had asserted, Sylvius replied that the bones were harder and more solid among the ancients, and were, in consequence,destitute of medullary substance. Again, when Vesalius showed that Galen was wrong in describing the human femur and humerus as greatly curved, Sylvius explained the discrepancy by saying that the wearing of narrow garments by the moderns had straightened the limbs.
Through these attacks, however, the writings of Vesalius fell into somewhat bad odour in the court; for in that very superstitious age there was a kind of vague dread felt of reading the works of a man against whom such serious charges of arrogance and impiety were brought. And so it came about that when he received the summons to take up his residence permanently at Madrid, and the orthodoxy of the day seemed for the moment to triumph, in a fit of proud indignation, he burned all his manuscripts; destroying a huge volume of annotations upon Galen; a whole book of medical formulæ; many original notes on drugs; the copy of Galen from which he lectured, and which was covered with marginal notes of new observations that had occurred to him while demonstrating; and the paraphrases of the books of Rhases, in which the knowledge of the Arabian was collated with that of the Greeks and others. The produce of the labour of many years was thus reduced to ashes in a short fit of passion, and from this time Vesalius lived no more for controversy or study. He gave himself up to pleasure and the pursuit of wealth, resting on his reputation and degenerating into a merecourtier. As a practitioner he was held in high esteem. When the life of Don Carlos, Philip's son, was despaired of, it was Vesalius who was called in, and who, seeing that the surgeons had bound up the wound in the head so tightly that an abscess had formed, promptly brought relief to the patient by cutting into the pericranium. The cure of the prince, however, was attributed by the court to the intercession of St. Diego, and it is possible that on the subject of this alleged miraculous recovery Vesalius may have expressed his opinion rather more strongly than it was safe for a Netherlander to do. At any rate, the priests always looked upon him with dislike and suspicion, and at length they and the other enemies of the great anatomist had their revenge.
A young Spanish nobleman had died, and Vesalius, who had attended him, obtained permission to ascertain, if possible, by a post-mortem examination, the cause of death. On opening the body, the heart was said—by the bystanders—to beat; and a charge, not merely of murder, but of impiety also, was brought against Vesalius. It was hoped by his persecutors that the latter charge would be brought before the Inquisition, and result in more rigorous punishment than any that would be inflicted by the judges of the common law. The King of Spain, however, interfered and saved him, on condition that he should make a pilgrimage to the Holy Land. Accordingly he set out from Madrid for Venice, andthence to Cyprus, from which place he went on to Jerusalem, and was returning, not to Madrid, but to Padua, where the professorship of physic had been offered him, when he suffered shipwreck on the island of Zante, and there perished miserably of hunger and grief, on October 15, 1564, before he had reached the age of fifty. His body was found by a travelling goldsmith, who recognized, notwithstanding their starved outlines, the features of the renowned anatomist, and respectfully buried his remains and raised a statue to his memory.
Two of the works of this great man have been already referred to, namely: "De Corporis Humani Fabrica;" "De usu Radicis Chinæ." Besides these the following have appeared: "Examen Observationum Gabrielis Fallopii;" "Gabrielis Cunei Examen, Apologiæ Francisci Putei pro Galeno in Anatome;" a great work on Surgery in seven books.
With respect to the last of these, it may be sufficient to remark that there is every reason to believe that the name of the famous anatomist was stolen after his death to give value to the production, which was compiled and published by a Venetian named Bogarucci; and that Vesalius is not responsible for the contents.
The other works are undoubtedly genuine. In 1562 Andreas seems to have been roused for a short time from the lethargy into which he had sunk, by an attackfrom Franciscus Puteus; for to this attack a reply appeared—from a writer calling himself Gabriel Cuneus—which has always been attributed by the most competent authorities to Vesalius himself. In this rather long work, covering as it does more than fifty pages in the folio edition, the views of Vesalius, which are at variance with Galen, are gone throughseriatimand defended.
In 1561 Fallopius, who had studied under Vesalius, published his "Anatomical Observations," containing several points in which he had extended the knowledge of anatomy beyond the limits reached by his master. He had taught publicly for thirteen years at Ferrara, and had presided for eight years over an anatomical school, so that he was no novice in the field of biology. Yet so completely had Vesalius lost the philosophic temperament that he regarded this publication as an infringement of his rights, and in this spirit wrote an "Examen Observationum Fallopii," in which he decried the friend who had made improvements on himself, as he had been decried for his improvements on Galen. The manuscript of this work, finished at the end of December, 1561, was committed by the author to the care of Paulus Teupulus of Venice, orator to the King of Spain, who was to give it to Fallopius. The orator, however, did not reach Padua until after the death of Fallopius, and he consequently retained the document until Vesalius, on his way to Jerusalem, took possessionof it, and caused it to be published without delay. It appeared at Venice in 1564.[19]
The letter on the China root—a plant we know nowadays as sarsaparilla—by the use of which the emperor's recovery was effected, has been already referred to. It was addressed to the anatomist's friend, Joachim Roelants. Very little space, however, is taken up with a description of the medicine which gives title to the letter. Something certainly is said of the history and nature of the plant, the preparation of the decoction and its effects; but the writer soon introduces the subject which was at that time of very vital importance to him, namely, his position with regard to the statements of Galen and his followers. He collects together various assertions of the Greek anatomist, on the bones, the muscles and ligaments, the relations of veins and arteries, the nerves, the character of the peritoneum, the organs of the thorax, the skull and its contents, etc., and shows from each and all of these that reference had not been made to the human subject, and that therefore the statements were unreliable.
To the work on the "Fabric of the Human Body" we have already alluded, as well as to the causes which led to its being written. More than half of this great treatiseis occupied with a minute description of the build of the human body—its bones, cartilages, ligaments, and muscles. It may have been owing to the thorough acquaintance which Vesalius showed with these parts that his detractors pretended afterwards that he only understood superficial injuries. But other branches of anatomy are fully dealt with. The veins and arteries are described in the third book, and the nerves in the fourth; the organs of nutrition and reproduction are treated of in the next; while the remaining two books are devoted to descriptions of the heart and brain.
Vesalius gives a good account of the sphenoid bone, with its large and small wings and its pterygoid processes; and he accurately describes the vestibule in the interior of the temporal bone. He shows the sternum to consist, in the adult, of three parts and the sacrum of five or six. He discovered the valve which guards theforamen ovalein the fœtus; and he not only verified the observation of Etienne as to the valve-like fold guarding the entrance of each hepatic vein into the inferior vena cava, but he also fully described thevena azygos. He observed, too, the canal which passes in the fœtus between the umbilical vein and vena cava, and which has since been known as theductus venosus. He was the first to study and describe the mediastinum, correcting the error of the ancients, who believed that this duplicature of the pleura contained a portion of the lungs. He described theomentum and its connections with the stomach, the spleen, and the colon; and he enunciated the first correct views of the structure of the pylorus, noticing at the same time the small size of the cæcal appendix in man. His account of the anatomy of the brain is fuller than that of any of his predecessors, but he does not appear to have well understood the inferior recesses, and his description of the nerves is confused by regarding the optic as the first pair, the third as the fifth, and the fifth as the seventh. The ancients believed the optic nerve to be hollow for the conveyance of the visual spirit, but Vesalius showed that no such tube existed. He observed the elevation and depression of the brain during respiration, but being ignorant of the circulation of the blood, he wrongly explained the phenomenon.
Exclusively an anatomist, he makes but brief references in his great work to the functions of the organs which he describes. Where he differs from Galen on these matters he does so apologetically. He follows him in regarding the heart as the seat of the emotions and passions—the hottest of all the viscera and source of heat of the whole body; although he does not, as Aristotle did, look upon the heart as giving rise to the nerves. He considers the heart to be in ceaseless motion, alternately dilating and contracting, but the diastole is in his opinion the influential act of the organ. He knows that eminences or projections are present in the veins, and indeed speaks ofthem as being analogous to the valves of the heart, but he denies to them the office of valves. To him the motion of the blood was of a to-and-fro kind, and valves in the veins acting as such would have interfered with anything of the sort. He expresses clearly the idea, that was entertained in the old physiology, of the attractions exerted by the various parts of the body for the blood; and especially that of the veins and heart for the blood itself. "The right sinus of the heart," he says, "attracts blood from the vena cava, and the left attracts air from the lungs through thearteria venalis(pulmonary vein), the blood itself being attracted by the veins in general, the vital spirit by the arteries." Again, he speaks of the blood filtering through the septum between the ventricles as if through a sieve, although he knows perfectly well from his dissection that the septum is quite impervious.
It will thus be seen that the physiological teaching of Galen was left undisturbed by Vesalius.