ANDREAS VESALIUS (1514‑64)

Modern plant study became effective with a happy combination of humanistic learning, Renaissance art, and the perfected craft of printing. The same is no less true of the study of the animal body. The real father of modern anatomy was the Fleming, ANDREAS VESALIUS (1514‑64), whose work brings out this combination admirably.

Even as a boy Vesalius was always observing Nature and dissecting the bodies of animals. He studied first at Louvain in his native Belgium and afterwards at Paris. Both universities were extremely conservative. Anatomical instruction was still medieval and pinned to the texts of Galen. Vesalius was highly successful as student and teacher there, and he became very learned in Galen. Fortunately for himself and for the world he quarreled with his superiors and decided to seek his fortune elsewhere. He determined on Italy, was appointed professor at Padua 0537), and immediately introduced sweeping reforms.

In the old days of Mondino the professor had dissected on his own account. The successors of Mondino abandoned this difficult and tiring process. They were content to read their lectures from the text of Galen, while a demonstrator (Latin demonstro, `I point out') indicated the parts to the students. Hence our modern academic titles Reader or Lecturer (lego, ' I read') and Demonstrator. The basic reform of Vesalius was to do away with demonstrators and other intermediaries between himself and the object `to put his own hand to the business', as he called it. His drive was irresistible. In five years he had completed and printed the masterpiece on which his fame is based, and he was still only twenty‑eight. He did no further important work. Vesalius's On the Fabric of the Human Body (Basel, 1543) is both the first great modern work of science and a foundation‑stone of modern biology.

The book opens with a description of the bones and joints, the general classification of which is from Galen. The first bone considered is the skull. It is astonishing to find here an examination in the modern manner of the different shapes of human skulls. Anthropologists to‑day attach great importance to these. Skulls are systematically measured and individuals and races classed as broad‑headed, long‑headed, round‑headed. This is exactly what Vesalius does. He follows this matter up by comparing the skull of man with that of certain animals, notably the dog.

Of all the subjects of which Vesalius treats, he is most successful with the muscles. In certain respects his representations of these are actually superior to most modern anatomical figures. Vesalius, with an artist's eye, has succeeded in representing the muscles with their normal degree of contraction.' In other words, he has represented living anatomy. This is a more difficult task, and one involving more real knowledge, than any presentation of the details of dead structures. For this reason naturalists still return to these figures of Vesalius and have something to learn from them, although they were prepared 400 years ago.

The account by Vesalius of the structure of the heart has a special interest. The workings of the heart and blood system had always been a puzzle. The current solution was that of Galen, which depends on the supposed existence of pores in the septum between the ventricles. Vesalius generally follows the physiological view of Galen. When, however, he comes to the septum between the ventricles he is mystified. He tells us that

'The septum is formed from the very densest substance of the heart. It abounds on both sides with pits. Of these none, so far as the senses can perceive, penetrate from the right to the left ventricle. We wonder at the art of the Creator which causes blood to pass from right to left ventricle through invisible pores.'

Thus he was not satisfied with Galen's view. Twelve years later he brought out a second edition of his great book. He has again examined the pits on the septum. This time he says

'Although sometimes these pits are conspicuous, yet none, so far as the senses can perceive, passes from right to left ventricle . . . not long ago I would not have dared to turn aside even a hair's breadth from Galen. But the septum of the heart is as thick, dense, and compact as the rest of the heart. I do not see, therefore, how even the smallest particle can be transferred from the right to the left ventricle through the septum.'

This attitude to Galen makes it evident that we are on the eve of a scientific revolution. Men are no longer satisfied with the traditions of the ancients. In this Vesalius was not alone. He was but the first of a whole line of Paduan anatomists that leads on continuously to the great biological awakening of the seventeenth century.