Part 18

FIG. 30. DRAWING OF DISSECTION OF THE HEART by Leonardo da Vinci. The modern names of some of the more important parts have been added.

It must be remembered that Leonardo did not publish his researches. It is only recently that his note-books have become fully accessible. But although Leonardo’s work remained in manuscript, it must not be assumed that his views were wholly without effect on his contemporaries. At any rate, soon after his time the questions that he had raised concerning the heart and blood-vessels were attracting others and were generally regarded as forming an important problem needing solution.

The task of writing an anatomical text-book based on direct observation, to which Leonardo did but put his hand, was achieved by one who was only four years old at the time when the great artist died. The central place in the unfolding drama is occupied by Andreas Vesalius of Brussels (1514-64). This extraordinary man studied first at the University of Louvain and afterwards at Paris. Anatomical instruction at these Universities had not improved much, if at all, on that of the Middle Ages. Vesalius soon tired of hearing long passages of Galen read out by the professor. He therefore resolved to go to northern Italy, where newer methods were being practised. Padua was the place of his choice. He immediately made his mark there, and was himself appointed professor when only twenty-four years of age. He established a scientific tradition at Padua which that University has retained to this day.

No sooner was Vesalius settled at Padua than he applied himself with unparalleled diligence to lecturing and research. Students crowded to hear him (Fig. 31). To aid them he issued, in 1538, a short guide to anatomy and physiology. An examination of this shows that his physiological views were still those of Galen and Aristotle. After its issue Vesalius found that Galen and Aristotle were by no means always to be trusted. The realization of this led him constantly to doubt any statement by them. His scepticism was sometimes excessive, but it led him to put every statement made by his predecessors to the test of experience. This gives his later work an epoch-making value.

It shows a dissection scene at Padua. In the center stands Vesalius dissecting a female body. At the head of the table stands an articulated skeleton. At its foot are dissecting instruments. Eager students throng around. In the foreground attendants are squabbling. On one side an attendant holds a monkey, one on the other a dog, for Vesalius had often to resort to animal in lieu of human anatomy. Shut off by a bar are members of the lay public. Gallants, grey-bearded scholars, monks, and an enthusiastic bookworm may be discerned among them. Other observers crowd in from every vantage point, even from the windows in the roof. The naked man to the left has been used by Vesalius to demonstrate the surface markings of the underlying organs. The whole scene is busy and vigorous in the extreme. It should be contrasted with the academic calm of Fig. 28 drawn fifty years earlier. ]

During the next four years Vesalius had ampler opportunities to dissect than he had yet encountered. He devoted a fiery energy to the preparation of his great work. The Fabric (that is ‘workings’, compare German ‘Fabrik’) of the Human Body was printed in 1543, a magnificent and beautifully illustrated volume. It is a landmark in the History of Science, and a wonderfully full record of a prodigious number of accurately recorded discoveries and investigations made by a single observer.

The masterpiece of Vesalius is not only the foundation of modern Medicine as a science, but the first great positive achievement of Science itself in modern times. As such it ranks with another work that appeared in the same year, the treatise of Nicholas Copernicus, On the Revolutions of the Celestial Spheres. The work of Copernicus removed the Earth from the center of the Universe; that of Vesalius revealed the real structure of man’s body. Between the two they destroyed for ever the medieval theories on the subjects of which they treat. But the work of Copernicus is one of close and subtle reasoning, still retaining many medieval elements, and is hardly a great exposition of what we now call the ‘Experimental Method’. The work of Vesalius far more nearly resembles a modern scientific monograph than does the treatise of Copernicus.

The achievement of Vesalius was very well received by the scientific world. Nevertheless, soon after its publication, Vesalius resigned his professorship to take up the position of a court physician to the Emperor Charles V, the great monarch of the age. He was then only twenty-nine years old, but his scientific career was closed.

The edition of the Fabric was soon exhausted, and the demand for more copies was met by imitations of the work by other hands. At last, in 1555, Vesalius was induced to issue a second edition. This contains certain changes in point of view that are important for the subsequent development of physiology. Vesalius now no longer merely hints his doubts as to the character of Galen’s physiology; he openly asserts that he is unable to verify its fundamental bases.

We may take a single instance of this new outspokenness. In his description of the septum of the heart, he had written in the first edition:

‘The septum of the ventricles of the heart is very dense. It abounds with pits on both sides. Of these pits none, so far as the senses can perceive, penetrate from the right to the left ventricle. We are thus forced to wonder at the art of the Creator, by which the blood passes from right to left ventricle through pores which elude the sight.’ (Compare Fig. 21, p. 59.)

This passage is altered to something quite different in the second edition, where he writes:

‘Although sometimes these pits are conspicuous, yet none, so far as the senses can perceive, passes from the right to the left ventricle. I have not come across even the most hidden channels by which the septum of the ventricles is pierced. Yet such channels are described by teachers of Anatomy, who have absolutely decided that the blood is taken from the right to the left ventricle. I, however, am in great doubt as to the action of the heart in this part.’

He further sets forth his whole policy with reference to Galen’s view in the following interesting passage:

‘In considering the structure of the heart and the use of its parts, I bring my words for the most part into agreement with the teachings of Galen; not because I think these on every point in harmony with the truth, but because, in referring at times to new uses and purposes for the parts, I still distrust myself. Not long ago I would not have dared to diverge a hair’s breadth from Galen’s opinion. But the septum is as thick, dense and compact as the rest of the heart. I do not, therefore, see how even the smallest particle can be transferred from the right to the left ventricle through it. When these and other facts are considered, many doubtful matters arise concerning the blood-vessels.’

The work terminates with a little chapter On the dissection of living animals. We note that this, while dealing skilfully with the methods of physiological experiment, does not exhibit any very marked advance on the views of Galen.

Among the experiments on living animals that Vesalius enumerates are excision of the spleen, the loss of which he showed was consistent with life; and the cutting of the nerves that supply the organ of voice, with resultant loss of that faculty. He demonstrated that longitudinal section of a muscle interferes little with its function, but cross section produces disability in proportion to the injury. Such experiments had been performed by Galen, who had also reached the same conclusion as Vesalius, that it is through the spinal cord that the brain acts on the various muscles of the limbs and trunk. Vesalius repeated Galen’s experiments on section of the spinal cord (p. 58). The most striking of his experiments were those on respiration. Here he showed that, even though the chest-wall be pierced, the animal may be kept alive if the lungs are continuously aerated by means of a bellows, and that a flagging heart may be revived by similar means.

The work of Vesalius at once placed the knowledge of the human body in a new position. It cannot be said that he completed the task of describing the naked-eye structure of the human body. Yet he went so far towards this that no dramatic improvement has since been made upon his methods. It is a fair statement that the whole of modern Descriptive Anatomy may be treated as a comment and correction and amplification of Vesalius. His work moreover stimulated a host of investigators.

It is beautifully and dramatically posed, and the drawing is remarkably accurate. The figure leans against a tomb, contemplating a skull. In the front left-hand corner of the top of the tomb is a part of the bony structure which supports the organ of voice (H).

The inscription on the tomb may be translated ‘Man’s spirit lives. The rest is Death’s portion’.

The inscription at the top may be translated: ‘A delineation from the side of the bones of the human body, freed from the other structures which they support and placed in their correct positions.’ ]

§ 2. The Anatomical Reaction on Surgery.

The immediate effect of the new knowledge of Anatomy was an improvement in Surgery. The Wars of Religion of the sixteenth and seventeenth centuries were fierce and prolonged, and the army surgeons of the time had much experience of the treatment of wounds. The most prominent of the military practitioners was the Frenchman, Ambroise Paré (1517-90). He perceived the importance of anatomical knowledge and adapted his discoveries to the needs of Surgery. Paré did much to elevate the surgeon’s profession from a despised handicraft to a position equal to that of other branches of the healing art.

Apart from the introduction of anatomical discipline into Surgery, Paré’s four contributions to the surgical art were, firstly, his discovery that gunshot wounds are not ‘poisonous’ as had theretofore been thought, and that therefore they do not require the application of boiling oil, but are best healed by soothing applications; secondly, the cognate doctrine that bleeding after amputations should be arrested, not by the terrible method of indiscriminate use of the red-hot cautery, but by simple ligature; thirdly, his advocacy of the method of turning the child in its mother’s womb before delivery in certain abnormal cases; and fourthly, his ingenious devising of artificial limbs (Fig. 33). None of these four was without precedent. Nevertheless, the eminence, skill, and wide experience of Paré were the main factor in the spread of these practices. But the greatest of all Paré’s contributions to surgery was the service of his own personality, the example of his steadfast efforts to increase his knowledge of human anatomy and his skill in the art, and his constant emphasis on the surgeon’s duty to exert his utmost efforts to avoid or relieve the patient’s suffering.

FIG. 33. ARTIFICIAL ARMS AND HANDS, designed and figured by Ambroise Paré, and used by him for wounded soldiers from about 1560 onwards.

In a famous passage Paré describes how he, a ‘freshwater soldier’, on his first campaign, watched the other surgeons following the old rule of treating all gunshot wounds with boiling oil. At first he formed his practice on theirs. The theory was that gunshot wounds contained a poison, which the boiling oil was believed to drive out. Paré tells of his agitation when one evening, his supplies having run out, men had to be treated without the boiling oil. Next morning he was astonished to find that every man whose wounds had been treated only with a salve had rested fairly comfortably, while all who had undergone the customary treatment were, as we may well believe, in great pain. ‘Then I resolved within myself never so cruelly to burn poor wounded men.’ Another saying of the shrewd old surgeon is the famous adage ‘I dressed him and God cured him.’

Paré’s works were frequently reprinted and translated into various European languages, including English. They exercised the widest influence on surgical craft in the sixteenth and seventeenth centuries. Like Vesalius, he is an example and type of a large class. In every country surgeons arose who made an effort to utilize the new anatomical knowledge.

§ 3. The Renaissance of Internal Medicine.