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The history of bloodletting has been marked by controversy. The extensive literature on bloodletting contains numerous polemical treatises that both extol and condemn the practice. Bloodletting was no sooner criticized as ineffective and dangerous than it was rescued from complete abandonment by a new group of zealous supporters.

From the time of Hippocrates (5th century B.C.)—and probably before, although no written record is available—bloodletting had its vocal advocates and heated opponents. In the 5th century B.C. Aegimious of Eris (470 B.C.), author of the first treatise on the pulse, opposed venesection, while Diogenes of Appolonia (430 B.C.), who described the vena cava with its main branches, was a proponent of the practice. Hippocrates, to whom no specific text on bloodletting is attributed, both approved and recommended venesection.[3]

The anatomist and physician Erasistratus (300-260 B.C.), was one of the earliest physicians to leave a record of why he opposed venesection, the letting of blood from a vein. Erasistratus, who practiced at the court of the King of Syria and later at Alexandria, a celebrated center of ancient medicine, recognized that the difficulty in estimating the amount of blood to be withdrawn and the possibility of mistakenly cutting an artery, tendon, or nerve might cause permanent damage or even death. Since Erasistratus believed that only the veins carried blood while the arteries contained air, he also feared the possibility of transferring air from the arteries into the veins as a result of venesection. Erasistratus was led to question how excessive venesection differed from committing murder.[4]

Through the writings of Aulus Cornelius Celsus (25 B.C.-?), the Roman encyclopedist, and Galen (ca. A.D. 130-200) venesection was restored as a form of orthodox medical treatment and remained so for the next fifteen hundred years. By the time of Celsus, bloodletting had become a common treatment. Celsus remarked in his well-known account of early medicine: “To let blood by incising a vein is no novelty; what is novel is that there should be scarcely any malady in which blood may not be let.”[5] Yet criticism of bloodletting continued, for when Galen went to Rome in A.D. 164 he found the followers of Erasistratus opposing venesection. Galen opened up discussion with these physicians in two books, Against Erasistratus and Against the Erasistrateans Dwelling in Rome. These argumentative dialectical treatises, together with his Therapeutics of Venesection, in which he presented his theory and practice of venesection, established Galen’s views on bloodletting, which were not effectively challenged until the seventeenth century.[6]

The fundamental theory upon which explanations of health and disease were based, which had its inception in ancient Greek thought and lasted up to the eighteenth century, was the humoral theory. Based on the scientific thought of the Pre-Socratics, the Pythagoreans, and the Sicilians, this theory posited that when the humors, consisting of blood, phlegm, yellow bile, and black bile, were in balance within the body, good health ensued. Conversely, when one or more of these humors was overabundant or in less than adequate supply, disease resulted. The humors were paired off with specific qualities representing each season of the year and the four elements according to the well-accepted doctrine of Empedocles, in which all things were composed of earth, air, fire, and water. Thus, yellow bile, fire, and summer were contrasted to phlegm, water, and winter, while blood, air, and spring were contrasted to black bile, earth, and autumn. When arranged diagrammatically, the system incorporating the humors, elements, seasons, and qualities appears as shown in Figure 1. The earliest formulation of humoralism was to be found in the physiological and pathological theory of the Hippocratic treatise, On the Nature of Man.[7]

Plethora, an overabundance of body humors, including blood, which characterized fevers and inflammations, was properly treated by encouraging evacuation. This could be done through drugs that purged or brought on vomiting, by starvation, or by letting blood. During starvation the veins became empty of food and then readily absorbed blood that escaped into the arteries. As this occurred, inflammation decreased. Galen suggested that instead of starvation, which required some time and evacuated the system with much discomfort to the patient, venesection should be substituted to remove the blood directly.[8]

Peter Niebyl, who has traced the rationale for bloodletting from the time of Hippocrates to the seventeenth century, concluded that bloodletting was practiced more to remove excess good blood rather than to eliminate inherently bad blood or foreign matter. Generally, venesection was regarded as an equivalent to a reduction of food, since according to ancient physiological theory, food was converted to blood.[9]

Figure 1.—Chart of elements, seasons, and humors.

Galen defined the criteria for bloodletting in terms of extent, intensity, and severity of the disease, whether the disease was “incipient,” “present,” or “prospective,” and on the maturity and strength of the patient.[10] Only a skilled physician would thus know when it was proper to bleed a patient. Venesection could be extremely dangerous if not correctly administered, but in the hands of a good physician, venesection was regarded by Galen as a more accurate treatment than drugs. While one could measure with great accuracy the dosages of such drugs as emetics, diuretics, and purgatives, Galen argued that their action on the body was directed by chance and could not easily be observed by the physician.[11] However, the effects of bloodletting were readily observed. One could note the change in the color of the blood removed, the complexion of the patient, and the point at which the patient was about to become unconscious, and know precisely when to stop the bleeding.

Galen discussed in great detail the selection of veins to open and the number of times blood might be withdrawn.[12] In choosing the vein to open, its location in respect to the disease was important. Galen recommended that bleeding be done from a blood vessel on the same side of the body as the disease. For example, he explained that blood from the right elbow be removed to stop a nosebleed from the right nostril.[13] Celsus had argued for withdrawing blood near the site of the disease for “bloodletting draws blood out of the nearest place first, and thereupon blood from more distant parts follows so long as the letting out of blood is continued.”[14]

Controversy over the location of the veins to be opened erupted in the sixteenth century. Many publications appeared arguing the positive and negative aspects of bleeding from a vein on the same side (derivative—from the Latin derivatio from the verb derivare, “to draw away,” “to divert”) or the opposite side (revulsion—from the Latin revulsio, “drawing in a contrary direction”) of the disordered part of the body. This debate mirrored a broader struggle over whether to practice medicine on principles growing out of medieval medical views or out of classical Greek doctrines that had recently been revived and brought into prominence. The medieval practice was based on the Moslem medical writers who emphasized revulsion (bleeding from a site located as far from the ailment as possible).[15] This position was attacked in 1514 by Pierre Brissot (1478-1522), a Paris physician, who stressed the importance of bleeding near the locus of the disease (derivative bleeding). He was declared a medical heretic by the Paris Faculty of Medicine and derivative bleeding was forbidden by an act of the French parliament. In 1518, Brissot was exiled to Spain and Portugal. In 1539, the celebrated anatomist, Andreas Vesalius, continued the controversy with his famous Venesection Letter, which came to the support of Brissot.[16]

Only with the gradual awareness of the implications of the circulation of the blood (discovered in 1628) did discussion of the distinction between derivative and revulsive bloodletting become passé.[17] Long after the circulation of the blood was established, surgical treatises such as those of Lorenz Heister (1719) recommended removing blood from specific parts of the body—such as particular veins in the arm, hand, foot, forehead, temples, inner corners of the eye, neck, and under the tongue. In the nineteenth century this practice was still challenged in the literature as a meaningless procedure.[18] (Figure 2.)

How Much Blood to Take

According to Galen, safety dictated that the first bloodletting be kept to a minimum, if possible. Second, third, or further bleedings could be taken if the condition and the patient’s progress seemed to indicate they would be of value. The amount of blood to be taken at one time varied widely.[19]

Galen appears to have been the first to note the amount of blood that could be withdrawn: the greatest quantity he mentions is one pound and a half and the smallest is seven ounces. Avicenna (980-1037) believed that ordinarily there were 25 pounds of blood in a man and that a man could bleed at the nose 20 pounds and not die.[20]

The standard advice to bloodletters, especially in the eighteenth and nineteenth centuries, was “bleed to syncope.” “Generally speaking,” wrote the English physician and medical researcher, Marshall Hall, in 1836, “as long as bloodletting is required, it can be borne; and as long as it can be borne, it is required.”[21] The American physician, Robley Dunglison, defined “syncope” in his 1848 medical dictionary as a “complete and, commonly, sudden loss of sensation and motion, with considerable diminution, or entire suspension of the pulsations of the heart and the respiratory movements.”[22] Today little distinction is made between shock and collapse, or syncope, except to recognize that if collapse or syncope persists, shock will result.

We know today that blood volume is about one-fifteenth to one-seventeenth the body weight of an adult. Thus an adult weighing 150 pounds has 9 or 10 pounds of blood in his body. Blood volume may increase at great heights, under tropical conditions, and in the rare disease polycythemia (excess red blood cells). After a pint of blood is withdrawn from a healthy individual, the organism replaces it to some degree within an hour or so. However, it takes weeks for the hemoglobin (the oxygen-bearing substance in the red blood cells) to be brought up to normal.

If blood loss is great (more than 10 percent of the total blood volume) there occurs a sudden, systemic fall in blood pressure. This is a well-known protective mechanism to aid blood clotting. If the volume of blood lost does not exceed 30 to 40 percent, systolic, disastolic, and pulse pressures rise again after approximately 30 minutes as a result of various compensatory mechanisms.[23]

Larger Image

Figure 2.—Venesection manikin, 16th century. Numbers indicate locations where in certain diseases venesection should be undertaken. (From Stoeffler, 1518, as illustrated in Heinrich Stern, Theory and Practice of Bloodletting, New York, 1915. Photo courtesy of NLM.)

If larger volumes than this are removed, the organism is usually unable to survive unless the loss is promptly replaced. Repeated smaller bleedings may produce a state of chronic anemia when the total amount of blood and hemoglobin removed is in excess of the natural recuperative powers.

When to Bleed

Selecting a time for bleeding usually depended on the nature of the disease and the patient’s ability to withstand the process. Galen’s scheme, in contrast to the Hippocratic doctrine, recommended no specific days.[24] Hippocrates worked out an elaborate schedule, based on the onset and type of disease, to which the physician was instructed to adhere regardless of the patient’s condition.

Natural events outside the body served as indicators for selecting the time, site, and frequency of bloodletting during the Middle Ages when astrological influences dominated diagnostic and therapeutic thought. This is illustrated by the fact that the earliest printed document relating to medicine was the “Calendar for Bloodletting” issued in Mainz in 1457. This type of calendar, also used for purgation, was known as an Aderlasskalender, and was printed in other German cities such as Augsburg, Nuremberg, Strassburg, and Leipzig. During the fifteenth century these calendars and Pestblatter, or plague warnings, were the most popular medical literature. Sir William Osler and Karl Sudhoff studied hundreds of these calendars.[25] They consisted of a single sheet with some astronomical figures and a diagram of a man (Aderlassmann) depicting the influence of the stars and the signs of the zodiac on each part of the body, as well as the parts of the anatomy suitable for bleeding. These charts illustrated the veins and arteries that should be incised to let blood for specific ailments and usually included brief instructions in the margin. The annotated bloodletting figure was one of the earliest subjects of woodcuts. One early and well known Aderlassmann was prepared by Johann Regiomontanus (Johannes Müller) in 1473. It contained a dozen proper bleeding points, each suited for use under a sign of the zodiac. Other Aderlassmanner illustrated specific veins to be bled. The woodcut produced by the sixteenth-century mathematician, Johannes Stoeffer, illustrated 53 points where the lancet might be inserted.[26]

“Medicina astrologica” exerted a great influence on bloodletting. Determining the best time to bleed reached a high degree of perfection in the late fourteenth and fifteenth centuries with the use of volvella or calculating devices adopted from astronomy and navigation. These were carried on a belt worn around the waist for easy consultation. Used in conjunction with a table and a vein-man drawing, the volvella contained movable circular calculators for determining the accuracy, time, amount, and site to bleed for an illness. The dangers of bloodletting elicited both civic and national concern and control. Statutes were enacted that required every physician to consult these tables before opening a vein to minimize the chance of bleeding improperly and unnecessarily. Consultation of the volvella and vein-man was more important than an examination of the patient.[27] (Figure 3.)

For several centuries, almanacs were consulted to determine the propitious time for bleeding. The “woodcut anatomy” became a characteristic illustration of the colonial American almanac. John Foster introduced the “Man of Signs,” as it was called, into the American almanac tradition in his almanac for 1678, printed in Boston. Other examples of early American almanacs featuring illustrations of bleeding include Daniel Leed’s almanac for 1693, printed in Philadelphia, and John Clapp’s almanac for 1697, printed in New York.

As in many of the medieval illustrations, the woodcut anatomy in the American almanac consisted of a naked man surrounded by the twelve signs of the zodiac, each associated with a particular part of the body (the head and face with Aries, the neck with Taurus, the arms with Gemini, etc.). The directions that often accompanied the figure instructed the user to find the day of the month in the almanac chart, note the sign or place of the moon associated with that day, and then look for the sign in the woodcut anatomy to discover what part of the body is governed by that sign. Bloodletting was usually not specifically mentioned, but it is likely that some colonials still used the “Man of Signs” or “Moon’s Man” to determine where to open a vein on a given day.[28]