The Tractate on Pestilential and Other Types of Fevers, by Abraham Caslari, a Jewish physician in Besalú, not far from Girona and at the eastern tip of Catalonia, was composed sometime in 1349. It is one of a number of extant tractates written during or immediately after the period of the Black Death, which reached Besalú in May 1348. As an early record of a physician’s perspective on the pandemic, Abraham’s tractate is important as a medical witness.For several reasons, Jacme d’Agramont’s Regiment de Preservacio is a useful foil to Abraham’s tractate. Jacme held the chair in medicine at the university in Lleida, a city located 200 kilometers west of Besalú. It was where Abraham and his family had spent several years following their expulsion from Languedoc in 1306. The Regiment de Preservacio was written in April 1348, making it the first known medical treatise to respond to the Black Death and the first original medical treatise produced at the University of Lleida. Jacme’s work was unique among the early tractates as the only example of a plague regimen written in the vernacular (in this case, Catalan) and intended for ordinary people. In contrast, Abraham Caslari’s tractate was intended for a reader learned in medicine and in Hebrew—not just the limpid biblical Hebrew of the Iberian Hebrew poets but the stilted, highly technical Hebrew that characterized medieval Hebrew philosophical and scientific prose.Whether the men were personally acquainted, or whether Abraham actually encountered Jacme’s text, we do not know. By the summer of 1348, like many of his fellow Lleidans and despite whatever preventive measures they implemented, Jacme would be dead of plague, and the Lleida aljama would be the target of a pogrom fueled by rumors blaming Jews for the pestilence. In contrast, and at the other end of the peninsula, Abraham treated many patients who, like him, survived the pandemic; his tractate was written after the fevers had ebbed and the violence to his west and south had quieted.Today, Jacme’s treatise is often invoked by historians for its claim that plague could be “manufactured” by evil men, a notion that has been linked to violence against local Jews. Indeed, Abraham’s treatise was written not just in the wake of a devastating outbreak of plague but in the wake of a series of violent attacks on local Jewish communities to the east, south, and west of Besalú. The nearest of those attacks, in April 1348, was in Perpignan, approximately 40 kilometers away. On May 17, when the plague had reached Besalú and Girona, the Jewish call (quarter) in Barcelona—approximately 130 kilometers to the south—was decimated and some 20 Jews killed; a domino series of attacks accompanied the plague west and south of Barcelona, causing varying degrees of destruction. (A second plague route through Iberia began in Majorca and touched the mainland in Almería, and then proceeded north and west.)Informed of the Barcelona attacks, King Pere IV of Aragon (also known as Pere III of Barcelona) sent letters to the cities of Cervera, Lleida, and Huesca ordering local authorities to protect their Jews. While the efficacy of these letters has been debated by scholars, there is evidence that municipal officials in these towns attempted to comply with their demands.There are no known records of anti-Jewish violence in Besalú or in Girona, the nearest city for which the impact of the plague has been studied. Still, it was likely that, by the summer of 1349, Abraham knew of the assaults on Jewish life and property elsewhere. In April 1348, a traveler from Provence to Girona had brought news of the arrest and torture of Jews accused of poisoning the water to cause plague in Narbonne, Carcassonne, and LaGrasse. By the following summer, when Abraham composed his tractate, refugees from Monzón, Tàrrega, and Solsona had sought shelter in Barcelona and surrounding towns, seeking refuge and redress; many refused to return to their ravaged homes despite enticements to do so.While some of the prominent Jewish physicians of his time were known also as men of letters, dedicating themselves to traditional religious texts and contemporary belles-lettres as well as to science, Abraham’s name is not linked to any belletristic achievement. In this respect, he differed from his father, David, who, in addition to his medical interests and writings, was a lover of poetry. A renowned physician in Narbonne, David translated a work by Galen from Latin into Hebrew. David also boasted a personal friendship with the local rhetorician and poet Abraham Bedersi, who dedicated a poem to him and nominated him to judge a poetry competition. David died in Catalonia in 1315 or 1316; we know of nothing that he wrote from the day he left France. In contrast, Abraham did invest time in writing, but as two of his three extant treatises attest, his abiding interest was not in poetry but fevers.A central argument of the Ma’amar beqaddahot divriyyot uminei qaddahot (Tractate on Pestilential and Other Types of Fevers) was that plague patients often suffered because physicians misdiagnosed the kind of fever that they were treating, confusing pestilential and nonpestilential fevers. As Melissa Chase has observed, this concern was shared by other plague authors, for whom fever was not (as now) a symptom but “a category of disease characterized by excess heat within the body.” Fevers, as a rule, might be divided into three categories based on the parts of the body that they primarily affected: hectic fevers originating in the solid members, ephemeral fevers in the spirits, and putrid (corrupting) fevers in the humors. Pestilential fevers differed because they began outside the body, with a corruption of the air; when inhaled, the bad air went to the heart, where it generated excess heat and moved to other organs. The buboes that appeared on plague victims represented the body’s attempt to expel excess heat to the “emunctory” closest to the affected organ (the groin, armpit, or neck)—what we now identify with the lymphatic network.Like a few of his contemporaries, Abraham was not convinced that the fevers of the past year were truly pestilential, despite their heavy mortality. While this view is not extraordinary, it holds interest because of Abraham’s description of a patient’s reasonable chances for survival if properly diagnosed. Some sick men and women recovered, he noted. But when physicians misdiagnosed the fevers that they were treating, patients often died unnecessarily.Significantly, studies of the impact of the Black Death in Girona, the nearest city for which I have found data, do conclude that the mortality rate there was markedly lower than in Barcelona or towns farther west. Guilleré estimated an overall mortality rate of 14.5% for Girona, which may be contrasted with the estimates of 40% to 60% or higher for Barcelona. Ironically, Abraham may be accurately describing the plague demographics suggested by modern historians, although he attributes the better survival rate among “his” patients to his greater medical expertise. The same pattern of thinking led later physicians to assume that they were more successful in treating subsequent plague outbreaks, which in general were not as deadly as the Black Death.Throughout the Tractate on Pestilential and Other Types of Fevers, Caslari refers to the opinions of both learned and not-so-learned physicians (respectively, those with whom he agrees and those with whom he does not), indirectly letting us know that he has been closely following the debates over the season’s fevers. It would have helped modern scholars had he named his sources and rivals; not atypically, he chose not to do so. His familiarity with the core medical reading of his time, especially Avicenna’s Canon, is nonetheless evident; some of the passages that Abraham cites from Avicenna’s work are also cited by Jacme. Despite Duran Reynals and Winslow’s claim that Abraham displayed ignorance of this learning, this is not surprising. Abraham, we recall, came from Narbonne, where Jewish medical learning and practice benefited from the prestige of medicine throughout Provence and Languedoc. The contemporary center for medical learning that would have influenced him was Montpellier, where the university faculty in medicine was renowned throughout Europe.Not far away, in Avignon, the papal court also attracted important physicians, some with faculty positions in Montpellier. Aragon imported physicians from Montpellier, while encouraging locally an “open” system of medical education that permitted non-Christian access to the profession in this region. Jews were not permitted to enroll at the universities but maintained a parallel system of instruction, largely through apprenticeships of young students to established physicians, and a licensing exam. Abraham Caslari was presumably trained by his father in this way. The so-called open system of licensing and practice in Aragon made it possible for Jewish physicians to follow the university curricula by means of a parallel corpus of translations that permitted them to master essential texts. When they were ready, the students were examined, often by a pair of examiners—one Christian, one Jewish—in the texts that constituted the formal university curriculuae.The terminology that Abraham uses to distinguish among various kinds of fevers supports the claim that he was familiar with the Canon. Avicenna begins book 4 of the Canon by defining fever as an “alien” heat that ignites and expands via the spirit and blood through the vessels of the body: Abraham defines a pestilential fever as an “alien” corruption of heat and humidity in the air: He repeats the term when describing fevers that cause putrefaction of the spirit. The same echoes of Avicenna that sound in Jacme’s work also sound in Abraham’s, underlining the systematic approach to their medical problem that sent both physicians back to this primary text. Jacme notes that in times of pestilence, “we see how serpents and other reptiles flee from their holes and issue hurriedly from them, the birds leave their nests and flee. … [W]heat and other fruits growing from the earth are affected and carry such great infection that they are like poisons to all who eat them.” Abraham writes that a pestilence caused by celestial change will be signaled on earth by changes in nature:For the Creator, blessed be He, gave animals [the ability to] sense when the air is good and to flee when it is bad and putrid, especially certain types of birds like crows, doves, and swallows.In fact, one reason he cites in defense of his argument that the mortality of the past months was not due to a universal pestilence (cosmological in origin) was that these signs were not in evidence:But these signs were not evident in the air, neither in the spring nor the fall, not in fogs or such, or in the fleeing of birds from their nests or reptiles from their holes. The fruit showed no more rot than usual for their nature.Both men’s claims rely on Avicenna’s Canon, book 4, which contains the author’s treatment of fevers. Avicenna also divides his discussion of pestilential fevers into causes, signs, and treatment. He notes that pestilential fevers have celestial and terrestrial causes and that celestial changes may be observed in the peculiar behavior of birds and reptiles on earth. In English, Me’ati’s medieval translation reads:Moreover, the signs as they appear for this cause may be that you see frogs multiplying in the water, and that you’ll see reptiles [or insects] generated by the corruption and what indicates [corruption]; you will see mice and animals that live in the earth flee, and you will see “bad-natured” animals like the stork, i.e., the agasim, and the like fleeing from their nests and departing, perhaps even abandoning their eggs.Jacme observes that pestilence can be local or general; it can begin in a single house or street or city and spread, or it can originate in a greater region. His analysis emphasizes the impact that local climate and, for that matter, lifestyle, could have on public health. The types of winds and air circulation that characterize a given locale, the ways people store food, the types of trees, “especially high ones such as poplars, which hinder the ventilation of the air, or walnut trees, which have a special tendency to corrupt the air, and also fig trees” will influence regional susceptibility to epidemics. So, too, local sanitation, or an area where animals are slaughtered or tanners work, can produce infection—particularly for someone predisposed by temperament to disease, which is also a “lifestyle” hazard encouraged by those who bathe or have sex too frequently, or who overeat and drink.Abraham similarly believes that corruption of the air can have an initial toxic effect on one or many people. Like Jacme, he notes that pestilence can begin in a house—even a part of a house—a city, or region and spread, and that bad diet or an unbalanced regimen can aggravate its effects. Again, both men echo the Canon, book 4, article 4, where Avicenna states that once corrupted air has entered the heart and spread to other organs, the result is pestilential fever—for those bodies who are susceptible to it. This includes people whose complexion is characterized by heat and humidity, but also people who have “bad humors” as a consequence of excessive behaviors, like people who indulge too much in sex. Jacme and Abraham also concur that local climate or individual susceptibility play a role in epidemic fevers. For Jacme, however, the diagnosis of “universal” pestilence made individual susceptibility less relevant, as the primary cause was divine. For Abraham, the fevers of 1348 were not a universal pestilence, and individual temperament mattered.Complexion (temperament) was relevant for Abraham even in terms of planetary influences, which primarily affect those persons and places predisposed to their influence:They will have no effect on those who are not predisposed to receive it, or on those whose complexion is contrary or divergent from this influence. Were this not the case, all the people found in pestilential air would get pestilential illnesses; [all] would die from them or [all] get well. But this is not the case, since some get sick and some do not, and the reason is the predisposition or lack of predisposition to this influence.Even his own treatise, he cautions his readers, should be read with the understanding that it describes the action of an individual disease in specific individuals. Every experience of illness is unique. Although he seeks to offer guidance in case this kind of fever should recur, the savvy reader will “add or subtract as his intellect recommends.This is not a point unique to Abraham but is one that he repeatedly emphasizes. He saw many people die, but not all of them, and for him, this variability demonstrates that the plague was not a universal pestilence. Likewise, he insists on modifications in his treatment plan based on the humoral complexion of the patient—which would be irrelevant in the case of universal pestilence. He begins his treatise with a sharp critique of the fatalities that he attributes to physicians’ misdiagnosis of the season’s fevers, whose “mixed” signs made them difficult to classify. Again, his observations may simply reflect his personal reality in the context of relatively low plague mortality rates in the Girona region. From Abraham’s perspective, however, the problem was not regional epidemiology but the physician’s failure to apprehend the true significance of his patients’ symptoms.For pestilential fevers, and for the “humoral-pestilential” fevers he diagnosed in his patients, Abraham offers a standard repertoire of remedies. To treat humoral-pestilential fevers, it is critical to strengthen the heart, and therefore foods that might be shunned in the case of pure pestilential fevers are cautiously allowed. Abraham admits that the fevers of the past year did not fit cleanly into any of these categories. Relying again on Avicenna, he notes that the pulse and urine of the patient might be deceptively normal, and then suddenly he would die:Thus their pulses and urine will be close to normal even as they are close to death. They [the corrupted humors] have reached the heart and brain so that the physician is unable to anticipate death.Thus, while they behaved in many respects like humoral-pestilential fevers, in other respects the recent fevers behaved as if the source of corruption were external and “poison-like.” For pestilential fevers, fumigations, and wood fires might counteract the corrupted substance of the air; Abraham adds familiar warnings to avoid exposure to “bad” air currents or breezes, to cover windows that let in air. Beneficial foods are those that emphasize astringent (cold, dry) qualities; they include citrus and poultry, land birds, and fish roasted in vinegar or pomegranate juice. Sweet fruits and dairy products, which increase humidity (phlegm) should be avoided, as should emetics and bleeding, which deplete the patient’s strength.But since fevers such as those experienced recently are not pure pestilential fevers, Abraham concludes his tractate with specific recommendations for fevers like those of the past year. Patients should be given silk compresses on their hands, face, and heart; arms and legs should be washed twice daily with herbal blends. Purging and bleeding are prescribed according to the number of days from the fever’s onset and the time of day. A mild emetic should target all the humors, “which are mixed in these sicknesses”; this is preferable to purgative drugs of bad or toxic qualities. Abraham prescribes ointments to combat headaches and recommends scenting the air lightly with myrtle, cinnamon, and citrus. Soups made with melon seeds, lentils, or chickpeas are good; almond milk, however, aggravates head pain. Meat and wine should be avoided, but since it is so important to bolster the patient’s strength, the rules may be bent: It is better for the patient to eat familiar foods than medically prescribed ones that are alien to his or her regimen. Unlike Jacme, Abraham offers no cost-cutting options for his recipes, which may say something about the social circles of his clientele; he does, however, indicate several times that dosages or remedies should be modified for children.The relative optimism of Abraham’s insistence on the ability of many patients to recover correctly reflects his experience treating them, but is unusual for the first generation tractates. As Ann Carmichael has noted, physicians rapidly rebounded from their initial sense of helplessness in encounters with the plague. Whether because subsequent outbreaks were less virulent, so that medical practitioners were convinced that their treatment regimens were successful, or whether repeated outbreaks dulled the shock of 1348, later tractates convey a tone of optimism and confidence notably lacking in the tractates of the first generation. Again, Abraham’s view of the fevers that he treated suggests a milder epidemiological context from that encountered elsewhere. That his experience was anomalous is also reflected in his exasperated disparagement of other physicians, some of whom presumably were located in cities and towns where the plague wrought greater devastation.The three Hebrew tractates besides Abraham Caslari’s that have been published to date are later 14th-century works responding to later plague outbreaks, but they are all from the same region and explicitly enlist the six nonnaturals, including consideration of the sixth nonnatural, “accidents of the soul.” The first, by Abraham ben Solomon Hen, recommends that the sick try to maintain good spirits to boost vital spirit. The second, an anonymous Sephardic tractate recently published by Bos and Mensching, elaborates on psychological factors to a surprising degree. In times of pestilence, the author states, it is important to make an effort to avoid sadness, worry, and melancholy, and likewise anger, “bad thoughts,” and isolation. All these things arouse bad humors and burn up the good ones. Thus it is critical to tilt to the other extreme and distance oneself from anger and bad things, “while rejoicing in one’s lot and giving praise to God for one’s life, enjoying companionship, good music, and tranquility.”In contrast, the question of psychological or emotional affect seems almost irrelevant to Abraham. In his defense, Avicenna’s Canon, book 4, does not emphasize these factors in its discussion of epidemic or pestilential fevers, either. The Canon, however, includes an impressive list of quotidian (ephemeral) fevers linked to affective causes that ranged from excessive joy to excessive fear, melancholy, fainting, or pain, and whose treatment calls upon remedies similar to those just mentioned. So, too, the treatise on fevers by Ibn al-Jazzar, which preceded Avicenna’s but, like his work, found a secure niche in the 13th- and 14th-century curricula of European Christian universities, understands one cause of short-cycle fevers to be excessive emotion. The author’s list includes “anger, grief, and fury,” for which he recommends treatment with “words and deeds that appease and please the soul,” as well as comforting diversions, friends, and aromatic plants. Abraham Caslari notes these categories when he considers the potential origins for putrefaction of spirit, some of which are humoral, and some in the heart or blood or spirit itself: “actions of the soul like anger and melancholy and others change the spirit’s [humoral] complexion.”Abraham may have assumed that physicians seeking a detailed treatment of this condition could consult other tractates; in several places, he mentions that he is eliding a topic because it is amply treated elsewhere. But even given this possibility, the total absence of psychological factors in Abraham’s tractate leaves a strange gap in the expected coverage of his subject matter. Only in the beginning of his tractate do we find a reference to “accidents of the soul”: When listing the signs of a true pestilential fever, Abraham refers to the power of fear, which, however, he medicalizes as a consequence of illness. Due to a suppression of vital spirit in the brain, the patient can experience lethargy, weakness, loss of appetite, and confusion. This physiological condition, in turn, creates “fear and a dread of death.” He offers no specific treatment to soothe or comfort the frightened patient.For Abraham, the physician’s primary goal when treating fevers like those that have ravaged Aragon is to maintain the strength of the patient’s heart. This may require cautious deviation from the regimens, especially if a patient yearns for a food that is not recommended. Here Abraham acknowledges a sort of psychological factor, by granting weight to a patient’s particular tastes or cravings.But the dietary cravings of a sick man are a meager concession to his mental anguish and fears. At the least, Abraham’s failure to address this category suggests that in a time of medical emergency, he did not think a patient’s emotional state was the physician’s priority. And perhaps, by extension, the low premium that Abraham set on “accidents of the soul” tells us something about his own temperament. A man who survives expulsion from his home, community, landscape, and language, and then rebuilds his life in a new setting, adding a new wife and language and powerful patronage in the construction of a flourishing career, is not a man who gives in to fearful imaginings.Alternatively, the lacunae tell us nothing of the sort, and Abraham simply chose to emphasize points of diagnosis and treatment that he felt were critical and on which he differed from prevailing medical opinion. A comparison with Abraham’s 1326 fever treatise, the “Alei ra’anan,” might bolster one view or the other. Alas, it is still unpublished, and for now, we can only say that for Abraham, his patients’ state of mind was not his most pressing medical concern, even that of patients he had lived among and perhaps treated for almost three decades.What can be learned from these three literary aspects of Abraham’s tractate? First, Abraham’s interjections and asides betray a glimpse of himself and his colleagues as they treated the sick. They furthermore testify to the heated debates taking place among medical professionals during the course of the plague and in its immediate aftermath. That debate began with questions of diagnosis that taxed received categories of disease (specifically, fevers) in new ways, pushing to the fore questions of transmission and contagion, as well as causality, and pressuring physicians to reconcile the gap between their experience and their books. Abraham’s insistence that the fevers should not be classified as universal pestilence is accompanied by his observation that many patients recovered. This anomalous assessment seems to reflect lower plague mortality in the vicinity of Girona and may partially explain the rejection of his view by other physicians (as well as his rejection of their plague realities).Second, albeit indirectly, the tractate also reflects the author’s distance from episodes of plague-inspired violence against Jewish communities—and equally from the sites of violence against lepers 27 years earlier. There is only one place in Abraham’s text where he may allude to anti-Jewish violence, and that is in his opening description of the trajectory of the pandemic. This description not only cites a biblical passage evocative of violent slaughter and dispossession but is also the identical passage invoked by a contemporary eyewitness of the violence in Monzón who survived to write about the attacks on the aljamas. The fact that it remains an isolated example makes it impossible to ascertain how consciously Abraham recycled Hayim Galipapa’s account.Abraham Caslari was a man who had survived his own dose of trauma and loss. His medical writings testify less to great gifts of intellect or synthesis than to his astounding resilience in a life that he had rebuilt from scratch and as a refugee in a foreign land with a father, wife, and children to support. His steady trajectory toward professional recognition, financial comfort, and political privilege document his canny mastery of the social and professional challenges that he faced along the way. In this sense, his personal quirks may be on display precisely where he believes he has escaped them: in ordered, technical prose. Conversely, Abraham’s prose betrays signs of stress. He worries that his views go unheard, he refers both to clinical and bookish disputes with other physicians, and he is tellingly contradictory in explaining his motives for writing. The fact, nonetheless, that he seeks to overcome these challenges in the form of a medical tractate reminds us that he saw his rivals as well as his followers as members of an intellectual and professional community whose language and commitments he continued to share in a time of crisis.Excerpted and adapted from Chapter 3 of After the Black Death: Plague and Commemoration Among Iberian Jews, by Susan L. Einbinder. Copyright © University of Pennsylvania Press 2018. Reprinted with permission of the University of Pennsylvania Press.