The 18th century, the century of the French encyclopedists and the great classifiers in the natural sciences, also began in medicine as an era of system builders. For the most part, these systems could not escape the defect of one-sidedness, and today they are as dead as the works that contained them. Yet the memory of one of those systematizers survives forever: Herman Boerhaave (1668–1738), professor at Leiden and unequaled in his time for his remarkable gifts as a clinician.
His lessons, given at the bedside of the sick, made him the true founder of clinical teaching. Although he had only twelve hospital beds at his disposal, one of his biographers stated that “beside those beds, the physicians of half of Europe were trained.” Like the ancient master of Cos, he gathered his observations in his Aphorisms, which achieved extraordinary circulation.
His eminent disciple, the Swiss Albrecht Haller (1708–1777), to whom we owe the monumental synthesis of the physiological knowledge of the time, demonstrated that irritability is a property of muscle fibers and that sensitivity, on the other hand, is intrinsic to nerve fibers.
Even more significant results rewarded the efforts of the great experimenter Lazzaro Spallanzani (1729–1779). He carried out profound studies on digestion, reproduction and regeneration, achieving, among other successes, the artificial fertilization of amphibians and mammals. By demonstrating that infusoria, or germs, did not develop in properly heated liquids, Spallanzani shook the traditional doctrine of spontaneous generation, anticipating an important aspect of Pasteur’s work.
His fellow countryman Giambattista Morgagni (1682–1771), a professor in Padua for sixty years, laid the foundations of a new medical discipline by linking in his research what the clinician observed with what the anatomist found on the dissection table. His monumental work, published when its author was already eighty years old, marked the starting point of modern pathological anatomy.
By connecting the causes and symptoms of diseases with the characteristic alterations of organs, Morgagni had given a new answer to the ancient question of what disease is. It was an answer completely unrelated to the old humoral pathology. His work opened the way for Xavier Bichat (1771–1802), who located the morbid process in the tissues, and for Rudolf Virchow (1821–1902), who ultimately placed it in the cells.
Meanwhile, the Englishman John Hunter (1728–1793) introduced a new spirit into surgery, beginning to support it with the results of physiology and pathology. He examined the mechanism that allows the ends of a ruptured tendon to reunite, investigated the process of consolidation in a fractured bone, studied the development of wound healing and, in short, made surgery, until then a merely technical art of treatment, begin to become a scientific discipline.
Franz Anton Mesmer (1734–1815) created animal magnetism, or mesmerism, and introduced magnetic therapy, which consisted of healing with the hands. According to his doctrine, the body possesses a circulating magnetic fluid from which a special force emanates, animating creation. Although medical corporations denied the effectiveness of this therapy, Mesmer became one of the most popular figures in Paris and, displaying extraordinary cures, earned considerable sums of money.
The experience of Mesmer and his school is an interesting chapter in the history of medicine, showing how far collective suggestion can go. At the same time, Samuel Hahnemann (1755–1843) founded homeopathy, which will be analyzed later.
Psychiatry may be considered to have been born in the 18th century. Philippe Pinel (1745–1826), impressed by a friend who suffered from mental illness, devoted himself to its study and published a book in 1801 in which he stated for the first time that mental illnesses were caused by organic alterations of the brain.
Around that time, medical journals and newspapers began to be published, which facilitated the rapid dissemination of scientific knowledge. The development and progress of medical science brought about a change in the practice of medicine. The physician consolidated his scientific and social position, abandoned alchemy and astrology, separated himself from philosophy and based his knowledge on the observation of the sick.
The practical physician, the origin of today’s clinician, stopped practicing surgery and obstetrics and became the family doctor. Anatomopathological thinking and the knowledge of pathology facilitated the formation of clinical schools, among which the Viennese school stood out.
Meanwhile, the Austrian Leopold von Auenbrugger (1722–1809), a physician in Vienna, enriched diagnosis with the discovery of percussion. Remembering that innkeepers tapped barrels in order to find out how full of liquid they were, he spent seven years gathering a satisfactory body of observations and developing an appropriate technique that would make it possible, by striking the surface of the chest wall, to recognize pathological alterations inside it.
He verified the data found in clinical research not only through post-mortem examinations, but also through a series of experiments, injecting liquids into the thorax of cadavers in order to demonstrate changes in sound in the injected area. However, his work met with the indifference of his contemporaries and might have remained unknown had the celebrated personal physician of Napoleon, Jean Nicolas Corvisart (1755–1821), not managed to secure for the invention the circulation it deserved.
A disciple of Corvisart, Laënnec (1781–1826) introduced a new procedure for exploring acoustic phenomena in the chest: auscultation by means of the stethoscope, a simple instrument that from then on would provide countless services in diagnosing heart and lung diseases.
By an irony of fate, Laënnec, the greatest clinician of his time, died at an early age, a victim of pulmonary tuberculosis, the very disease in whose study he had so greatly distinguished himself.
