The growth of medicine from the earliest times to about 1800

by Albert H. Buck

Iatrochemists and Iatrophysicists.—During the seventeenth century there was a great deal of disputing among physiologists about the nature of certain processes like assimilation and retrograde metamorphosis, about the manner in which blood is formed, about digestion, and about the rôle played by the lymph vessels. According to Haeser a large proportion of the physicians of that day were confident that chemistry was entirely competent to solve these riddles, and yet, on the other hand, there were not a few who believed that the science of physics, which was then much further advanced than that of chemistry, was quite as competent to explain all the phenomena. At first the split into these two factions was confined to men who were interested in questions of a purely physiological nature, but in a short time the practitioners of medicine were also drawn into the controversy; and from that time onward it became customary to employ the terms, “iatrochemists” and “iatrophysicists” in speaking of the partisans of the two schools of medicine (the iatrochemical and the iatrophysical or iatromechanical). The iatrochemists described digestion as an act that is essentially chemical in character, a form of fermentation; and by the latter term the more advanced members of this school—François Deleboë Sylvius (1614–1672), who was born in Hanau, Prussia, of Dutch parents, and who took his doctor’s degree in Basel in 1637, and Thomas Willis of London (1622–1675)—understood something quite different from our modern conception of fermentation. Their interpretation was as follows: “An internal chemical movement of matter which is set agoing and continued in action in the stomach and intestinal canal through the agency of certain chemical reagents.” (Haeser.) They attributed an important influence to the saliva, the pancreatic juice and the bile in effecting the changes mentioned. The iatrophysicists, on the other hand, and more particularly Archibald Pitcairn of Edinburgh, Scotland (1652–1713), and Giorgio Baglivi of Ragusa, Italy (1668–1707), described digestion as a purely mechanical breaking up of the elements of the food partaken—a “trituration.” As to the further fate of the resulting chyle (its mode of reaching the blood, for example) the two schools were in perfect accord.

Sprengel mentions it as an actual fact that, during the seventeenth century, there were several physicians who combined the two careers of teacher of medicine and hydraulic engineer (iatrophysicists or iatromathematicians).[76] Several events conduced to the formation, in Italy and in Great Britain, of a distinct iatromathematical school. Among them may be mentioned, first and foremost, Harvey’s discovery of the circulation of the blood; second, the spread of the doctrines taught by Descartes favored in a marked degree the union of medicine and mathematics (physiology, the iatromathematicians claimed, was only a branch of applied mathematics); and, third, the formation at Florence, in the middle of the seventeenth century, of an association of the pupils of Galileo. The objects of this association were to cultivate their master’s philosophy, to carry on the work of experimental physics, and to apply its principles in every department of natural science. Alphonso Borelli (1608–1679), Professor of Mathematics first at Messina and afterward at Pisa, the author of the famous treatise on “The Movements of Animals,” and the founder of the iatromathematical school, was a member of the association. In this connection it is important to mention another zealous worker in the field of iatromathematics, viz., Sanctorius Sanctorinus, of Capo d’Istria (1561–1636). His work was done quite independently of any general movement among scientific investigators and at a much earlier period than that during which the school flourished. He was quite successful, for example, in his attempts to measure the actual amount of imperceptible evaporation, and to determine the influence which this process exerts upon health and disease. In the course of these investigations in what he called “static medicine,” Sanctorinus invented a number of unusual instruments.

The phenomenon of the formation of schools or sects, the members of which were keenly interested in the maintenance and promulgation of certain physiological, pathological, or therapeutic doctrines, manifested itself anew, as I have shown above, in the seventeenth century. In the early years of the Christian era the partisans of different medical doctrines formed schools of this nature which flourished for a certain period of time and then died out completely. Such, for example, were the sects of the Dogmatists, the Methodists, the Pneumatists, etc. The mere fact of the existence of these different schools or sects showed unmistakably that the science of medicine was alive at that time and that its devotees were making vigorous efforts to increase their stock of knowledge. Then followed the long period of the Middle Ages, a series of many centuries, during which medicine made only slight gains; but at last came the Renaissance,—the fifteenth, sixteenth and seventeenth centuries,—and here again we have a recurrence of the same phenomenon of sects in medicine; but note the great difference between the earlier manifestations and those which I have just outlined. The present group, it is proper to remark, is merely the forerunner of several similar movements that are to occur during the eighteenth and nineteenth centuries, movements that are all based, in varying degrees, upon the truth.

The Employment of Latin in Lecturing and Writing on Medical Topics.—In all the countries of Europe, but more particularly in Germany, there existed during the sixteenth and seventeenth centuries—and for a long time subsequently—the practice of delivering all the lectures on medical topics in the Latin tongue—i.e., in a language which at best could not be easily understood by more than a small proportion of the students. Even the lecturers themselves must have been hampered in the full expression of their thoughts by this rule, which was practically compulsory. Paracelsus (1493–1534), the famous Swiss physician, tried—a full century earlier, as will be shown farther on—to break up this seemingly harmless but in reality objectionable custom; his example, however, was not followed, and the practice was continued without interruption for at least two centuries longer. The use of Latin as the language in which all medical knowledge was to be taught was undoubtedly based upon the idea that it was necessary for the educated physician to be reasonably familiar with that particular tongue, for the simple reason that it was the only one in which, in those early days in Western Europe, the writings of Galen were accessible, for nobody but a few expert scholars had yet acquired any useful knowledge of Greek, the language in which all of Galen’s works were originally written. But it is quite likely that with this motive, which certainly was intended to produce good and useful fruit, there was coupled the further idea that the great mass of irregular practitioners—the quacks, the early barber-surgeons (Wundaerzte), and the peripatetic physicians—would in this way be debarred from entering the ranks of the regularly trained physicians. It was only after the custom of using the Latin for lecturing and writing purposes had become thoroughly rooted in the minds of medical men as something right and proper, that it began to dawn upon the minds of some of the brighter men that this practice was harmful to the advance of medicine beyond the standards established by Galen. Vesalius, who was a contemporary of Paracelsus, fully appreciated how serious an obstacle to further progress in anatomical knowledge the teachings of Galen were, and it was he who made the first really successful attack on this great hindrance to further progress; but there is no evidence to show that he had the slightest idea that lecturing and writing about medical topics in Latin played any part in the perpetuation of the evil which he was fighting. To Paracelsus alone belongs the credit, so far as I know, of endeavoring, through the force of example and by spoken arguments, to break up the practice which we are here considering. I may be mistaken in the view which I have here expressed, but it is difficult for me not to believe that the habitual use of Latin as the proper vehicle for the transmission of facts and ideas belonging to the domain of medicine must have materially hindered the advancement of that science; for such use certainly tended to keep men’s minds moving in fixed ruts, and those ruts all led straight toward the faulty teachings of Galen.

CHAPTER XXIX
THE CONTRIBUTIONS MADE BY DIFFERENT MEN DURING THE RENAISSANCE, AND MORE PARTICULARLY BY WILLIAM HARVEY OF ENGLAND, TO OUR KNOWLEDGE OF THE CIRCULATION OF THE BLOOD, LYMPH AND CHYLE

Among the earliest known doctrines relating to the nature of the blood and its mode of distribution throughout the body are those attributed to Erasistratus and Galen; for the still more ancient ones, of which Diogenes of Apollonia, Aristotle and the Hippocratic writers are reputed to be the authors, are too incomplete to call for serious consideration in this place.

(a) The Doctrine Taught by Erasistratus.—Erasistratus, who was born at Julis in the Island of Ceos (Aegean Sea) during the third century before Christ, held the belief that the arteries contain only air, which is drawn into the lungs by way of the trachea and bronchi, whence it enters the pulmonary vein (called by him the “venous artery”). In its further course this air passes from the pulmonary vein into the left ventricle of the heart, and is then conveyed from that organ through the arteries to the different tissues of the body. Erasistratus further taught that the smallest subdivisions of both the arteries and the veins lie side by side in the tissues, and that, in certain abnormal bodily conditions, they communicate the one with the other through anastomoses; but that, in a normal condition of the body, no communication takes place between the two. In common with all other physicians of that time, he believed that only the veins carry blood. Here, then, we find the first glimmering of the truth with regard to the nature of the circulating medium and also with regard to the course which it pursues in one part of its circuit—that part, namely, where the two kinds of vessels become capillary in character. His substitution of air for blood in the arteries is plainly the principal error in his scheme.

(b) The Teaching of Galen and of Caesalpinus with Regard to the Nature of the Blood and Its Mode of Distribution.—Galen, in the second century of the present era, disputed the correctness of the doctrine taught by Erasistratus. His objections are thus stated: “Inasmuch as blood flows from an artery when it is wounded, one of two things must be the truth. Either blood was already contained in the vessel before it was wounded, or it must have found its way in from the outside. But, if the blood comes from the outside into a vessel which contains only air, then air must necessarily escape from that vessel (when wounded) before blood does—which is contrary to the fact, as blood alone flows out. Therefore arteries contain only blood.” As a further proof of the correctness of his statement Galen carried out the following experiment: In a living animal he placed two ligatures around an artery at points situated not far apart, and then made an opening in the vessel between the two ligatures. The intervening section of the artery, it was thus found, contained only blood. This experiment, it might reasonably be supposed, would have definitely settled the question; but such was not the case. The followers of Erasistratus immediately raised this objection: If the arteries contain blood, how may the air which is drawn into the lungs find its way to all parts of the body? Galen replied that the inhaled air does not pass through the lungs, but is rejected by them after it has cooled the blood. This refrigerating process, he claimed, constitutes the sole purpose of the respiratory act.

Although Galen’s idea regarding the true function of respiration is not in harmony with the doctrine taught by modern physiologists, it nevertheless represents a marked advance over the belief previously maintained. Even as recently as in the time of Albert von Haller (approximately 1760–1780) physicians still continued to believe that it was the function of respiration to cool the blood; and indeed it was scarcely possible before 1800 to offer a more correct physiology of the act of breathing, for it was not until after the lapse of many centuries that the advance in our knowledge of chemistry reached a point at which it became possible to find a satisfactory solution of so complicated a problem.

As to the nature of the blood itself Galen believed, as I have already stated more fully in Part I. (“Ancient Medicine”), that there are two kinds—spirituous blood (or spirit) and venous blood. He gave the name of spirituous blood to that which is found circulating in the arteries, and which is appreciably brighter in color than that which fills the veins. According to Flourens, the distinguished French physiologist of the nineteenth century, Galen was the first among the ancient anatomists to make this distinction of two different kinds of blood. To the spirituous variety Galen ascribed the function of nourishing the more delicately constructed organs like the lungs, while he claimed that the venous blood is suited to nourish only the coarser ones, like the liver, spleen, etc.