AND there was the impact of science upon medicine. The healing art was bound up with the improvement of the microscope and the thermometer, with the rise of chemistry and biology, and, above all, with the advancing knowledge of human and animal anatomy and physiology. Most of the researches in anatomy and physiology were the work of the doctors themselves.
Giovanni Battista Morgagni was typical of the many physicians who made medicine a science by keeping clinical records of the cases that came under their care. Seven hundred such cases were scrutinized by him in his devoted career as practitioner and professor of medicine at Padua. In his eightieth year (1761) he reported his observations in the form of seventy letters that founded pathological anatomy: De sedibus et causis morborum per anatomen indagatis (On the Seats and Causes of Diseases as Investigated by Anatomy). Here he gave classical descriptions of heart block, yellow atrophy of the liver, and tuberculosis of the kidney; he identified the clinical features of pneumonia with solidifications of the lungs; and he added significantly to cardiology. “The section on aneurysm [abnormal blood-filled dilation] of the aorta,” said Sir William Osler, “remains one of the best ever written”; and “what could be more correct than his account of angina pectoris?”1 Now, more clearly than ever before, the seat of each illness was localized in morbid alterations of specific organs. Impressed by Morgagni’s work, the hospitals—with no protest from Church or state—provided him and his assistants with cadavers from all classes of the community, even nobles and ecclesiastics; many individuals, in the wish to advance science, expressed a desire to have their bodies examined by Morgagni after their death.2 He made experiments on animals, again without protest from the Church. He continued to teach till his ninetieth year. In 1764, aged eighty-two, he was reported to be “as hale as a man of fifty, and still working without spectacles.”3 His students proudly proclaimed him “anatomicorum totius Europae princeps” In 1931 his native Forli raised a monument to him in the piazza that bears his name.
His pupil Antonio Scarpa became professor of anatomy at Modena at the age of twenty. When, aged thirty-six (1783), he was promoted to the chair of anatomy at Pavia, he joined Spallanzani and Volta in making that university one of the greatest in Europe. His anatomical studies of the ear, the nose, the feet, and the nerves won him international renown; his Osservazioni sulle principali malattie degli occhi (1801) continued for several decades to be the standard text of ophthalmology. Just a year younger than Scarpa, Félix Vicq-d’Azyr studied the comparative anatomy of birds, quadrupeds, and man; his results showed a remarkable and detailed similarity in the structure of the limbs in men and beasts, and shared in putting man in his biological place. He died at forty-six (1794), without having completed a work which had already brought the anatomy of the brain to its eighteenth-century peak.
In Great Britain two Hunters, born in Scotland, added brilliance to the Scottish Enlightenment by their work in anatomy and surgery. William’s lectures revolutionized the teaching of anatomy in London, where that subject had long been hampered by restriction on the availability of cadavers. He won fame by his epochal discovery (1758) of the absorbent function of the lymphatics, by his classic Anatomy of the Gravid Uterus (1774), and by his volcanic temper, which he explained on the ground that, being an anatomist, he was accustomed to “the passive submission of dead bodies.”4 He died in 1783, aged sixty-five, from exhaustion incurred in a lecture. He bequeathed his extensive anatomical collection to Glasgow, where it is still maintained as the Hunterian Museum.
John Hunter was born ten years after his brother, and died ten years after his brother’s death. At twenty-one (1749) he had acquired sufficient knowledge to take charge of William’s class in practical anatomy. While with his brother, he solved the problem of the descent of the testes in the foetus, traced the placental circulation and the ramifications of nasal and olfactory nerves, discovered the tear ducts, and took a leading part in exposing the functions of the lymphatic ducts. At twenty-seven he entered Oxford; however, finding Latin and Greek deader than cadavers, he left college and joined the army as a surgeon. In active service abroad he learned much about gunshot wounds; at his death he left a classic treatise on that subject. Back in England, he practiced and taught surgery, and continued his investigations of anatomy and physiology. In 1767 he met with an accident that ruptured his “tendon of Achilles” (which binds the muscles of the calf of the leg to the heel); from observations then made on himself, and from experiments on dogs, he found successful surgery for club feet and other deformities involving tendons. Having inadvertently inoculated himself with syphilis, he delayed its treatment in order to study the disease at first hand;5 however, he made the mistake of identifying syphilis with gonorrhea. He proved by experiment that digestion does not take place in snakes and lizards during hibernation. In his house at Brompton he gathered for his researches a weird menagerie of pheasants, partridges, toads, fish, geese, hedgehogs, silkworms, bees, hornets, wasps, an eagle, two leopards, and a bull. He nearly lost his life wrestling with the bull and recapturing escaped leopards. He anatomized over five hundred species of animals. He studied the effects of various toxins, and admitted in 1780 that he had “poisoned some thousands of animals.”
In 1785 he sat for his portrait to Reynolds, but at first proved too restless; Sir Joshua was about to abandon the sitting, when Hunter fell into a deep and motionless reverie which enabled the artist to make the sketch for the portrait now in the Royal College of Surgeons. Like his brother, John was of an irritable and imperious temper. Finding himself subject to angina pectoris, he said, “My life is in the hands of any rascal who chooses to annoy and tease me.”6 Contradιcted by one of his colleagues, he fell into a rage, and died within a few minutes (1793). He was buried in Westminster Abbey, next to the remains of Ben Jonson. His collection of thirteen thousand specimens was acquired by the Corporation of Surgeons through a governmental grant, and became in 1836 the Hunterian Museum of London. The “Hunterian oration” delivered in his memory is an annual event in the English medical world.
In physiology the great name of this period was Albrecht von Haller. We have met him as a poet in his youth; in his later years he placed himself at the head of his kind by his Elementa physiologiae Corporis humani, which appeared in eight volumes between 1757 and 1766. They not only recorded all the current lore of human anatomy and physiology, but included his own discoveries on the role of the bile in the digestion of fats, and on the irritability or contractility of muscle fibers independently of nerves and even when separated from the body. Diderot concluded from these and similar experiments, “If life remains in organs severed from the body, where is the soul? What happens to its unity? … to its indivisibility?”7 He argued from such evidence that all physiological processes are mechanical. Haller disagreed; the irritability of organic tissue, he felt, indicated a vital principle absent in inorganic substances and incompatible with a mechanistic philosophy. Further studies by Haller showed that “the structure of the bones of quadrupeds is essentially the same as that of birds,” and that “the bones in man are not different in any part of their structure from those of quadrupeds.”8 In 1755 he made the first recorded observation of atherosclerosis, the accumulation of mushy fat in the walls of the blood vessels. “When we open the pages of Haller,” said Sir William Foster, “we feel that we have passed into modern times.”9
Other investigations lent support to a mechanistic view. Robert Whytt showed (1751) that reflex actions need involve only a small segment of the spinal cord. The work of Priestley, Lavoisier, Laplace, and Lagrange seemed to reduce respiration to chemical processes analogous to combustion. Réaumur’s experiments (1752) proved that digestion results from the chemical action of gastric juices; Spallanzani showed (1782) that this action of the digestive juices upon food could go on even outside the stomach; and John Hunter discovered that after death these juices begin to digest the stomach wall itself.
Spallanzani was one of the major figures in eighteenth-century physiology. We have seen his experiments on “spontaneous” generation. His interest in digestion knew no bounds. He discovered the digestive function of saliva. He experimented on himself by stimulated vomiting, and by swallowing bags and tubes, which he patiently recovered from his stools. He was the first to show that the systolic contraction of the heart sends blood into the smallest capillaries. He showed that perspiration is not akin to respiration, but can, up to a certain point, take the place of breathing. Though an abbot, he became an authority on fertilization. He found that when the male organs of a frog were covered with waxed linen the female remained unfertilized after mating; but when he collected the male fluid from the linen, and placed it in contact with the female eggs, these became fertilized. He obtained artificial fertilization in mammals by injecting the sperm of a dog into the uterus of a bitch.10 The twentieth century finally appreciated the scope and significance of his indefatigable experiments, and recognized him as one of the elect in the priesthood of science.