The Canon of Medicine

¶ The first doubt concerning the nature of pepper and scammony.

A decorative woodcut initial 'A' featuring floral patterns and vine-like scrolls within a square border.

In Avicenna, there occur many and almost erratic, intermittent doubts—nearly infinite in number—of which it is worth the effort to touch upon certain notable and most remarkable ones. In the second Canon, he says: "A little pepper promotes urine, and much of it loosens the belly," according to the opposite of scamonea scammony, a purgative resin. Serapio and Aristotle hold the opposite view. Thus Serapio the Aggregator says in his Book of Questions: "If anyone uses much pepper, it promotes urine; and if he uses little of it, it causes the belly to become moist; but scammony is contrary in this." For the proper act of pepper is to provoke, while that of scammony is to loosen. Whence Aristotle says: "Or because both are more mobile in both ways: pepper indeed is diuretic, while scammony carries downwards; yet the improper act of pepper is to loosen, and that of scammony to provoke, into which they can also be altered by quantities." Thus, much pepper promotes, while a little loosens; but in scammony, the opposite occurs. Therefore, for reasons of this kind, it must be said that either Avicenna has been presented poorly or falsely, or that he understood "much" and "little" differently than Aristotle did, by diversifying the utility according to moderate and maximal amounts.

¶ The second doubt of Avicenna concerning the fever of the blood.

Avicenna acts wantonly against Galen regarding the fever of the blood; for it is not enough for him to criticize this man irrationally, but he also claims his discourse contains pure falsehood. And he brings a similar charge against him in the ninth [book] of Animals, claiming he [Galen] made a mistake regarding the half of each thing and knew much about the branches but was ignorant of the roots of science. Concerning the sequence of which, Galen opined in the fourth [book] that the fever of blood does not arise from its putrefaction, for when blood putrefies, it becomes bile and does not remain blood. Thus, a choleric fever occurs then and not a sanguineous one, such as causon burning fever and tertian fever, and he treats it with the cure for causon or tertian fever. Then Avicenna, attacking his discourse, claims it contradicts Hippocrates and does not align with the truth. For he assumes this statement: "When blood putrefies, it becomes bile." And he says that from this, one can derive a double understanding. One is that after the putrefaction has already occurred, the blood is converted into bile. The other is that this happens within the process of putrefaction itself, just as he mentions the discourse of Galen merely as a name. And therefore he condemned him more wantonly, for Galen does not assert it to be simply so, but with a certain modification: for he receives blood more closely than Avicenna, wherefore it can be quickly changed into bile. Averroes, although more hidden, seems to say the same thing as Galen; for in the third [book] he collects the chapter on the fever of blood. He says: Fevers of blood are generated on account of its departure from nature in quantity or quality; but its departure in quality must be slight, since when it is great, then the ailment must be attributed to the name of that ailment

to which it declines, and to that which dominates it manifestly. This is because when it is excessively inflamed, it must be attributed to bile. Concerning this, in the fourth of the same, he says of the fever of blood: It does not have a type, because the blood making it is in the veins. Except if it were to occur on account of an aposteme an abscess or tumor called flegmon inflammation, which might be generated in any of the principal members, such as in the liver or diaphragm. For then in this fever, the paroxysms will be tertian, similar to the paroxysms of bile, because when blood overheats, it declines to the nature of bile. Therefore, in such a fever, there is no difference between a choleric fever, whose matter is inside the veins, and this one, except in degree. I say, therefore, that since "more and less" does not vary the species, this fever of blood will ultimately be of the same species as the choleric, when the blood has been converted into bile. He says again: And the words of Galen are varied regarding the fever of blood, because sometimes he says that it is a continuous choleric fever, and sometimes that it is different from a choleric one, and that it ought not to be attributed to a choleric one unless one does not have perfect putrefaction, since the nature of this fever is intermediate between the fever of vici a type of fever and a putrid fever. In the seventh [book], he collects the chapter on the cures of burning fevers: there are two species of the fever of blood. One while the blood is not yet putrefied, and the other while the blood already begins to putrefy. He significantly says "while it begins to putrefy," because proceeding into putrefaction, it is transmuted into bile and its fever. Thus, therefore, as blood not much changed into putrefaction causes a sanguineous fever, when it is vehemently converted into bile, it will induce a tertian fever. Thus, therefore, is the correct intention of Galen explained, which Averroes imitates. And the defect of Avicenna is manifest, as Aponensis most learnedly writes, who perhaps, with a satirical intellect, looked only at the other, wishing to lacerate the prince of physicians, Galen, with a leonine bite, although in most places he confesses himself to be his interpreter.

¶ The third doubt of Avicenna concerning Conium, such as Hemlock.

A decorative woodcut initial 'H' featuring floral patterns within a square border.

Medical authors have disagreed among themselves most powerfully in the naming of Hemlock, and especially Avicenna with Galen. The cause of which could perhaps be twofold: one indeed because few of the former seem to understand conion as hemlock. The Arabs, however, think the matter itself is more likely henbane. Whence in the first and third of Medicaments, where in the Greek conion the Arab translated it as henbane; and where, according to the Arab, Galen has in the aforesaid that henbane is food for thrushes and poison to men; Avicenna in the second and first [books] wrote "monkshood" original: "napellum" under it. In the fourth, he wavers more, saying: Galen says in the third of Simples that it is Afarfas, and I estimate it to be monkshood or a killing poison. For it kills men and not thrushes, because on account of the narrowness of their veins, it does not reach their hearts unless it is vehemently altered; in man, however, it is different, the true cause of which is noted in the third of Complexions from the proportion of the agents and patients acting upon one another; and therefore Avicenna took this cause from him and attributed it to himself as if stealthily.

it stands regarding the former. And I say this mode is a certain one, hinting at the defect of Haly Abbas. For what reason in the practice of the art does it not harm? Since hemlock, where it is written in Greek as *conion*, cools humans, just as it cools blackbirds; for to them it is food. Just as it is not expedient that hellebore, since it is food for thrushes, should also be food for humans; where Constantine translated "henbane does not kill sparrows, rather it nourishes them," it is not necessary that humans should be nourished by hellebore or veratrum just as quails are. Whence Haly Abbas in the complexionum book of temperaments, the sequence of which he tries to interpret, says: "Conium is rarely food for a thrush, [but] a drug for a man; and again, hellebore is food for a thrush, but a drug for a man." How discordantly, therefore, does Haly Abbas interpret the sequence. Similarly, Avicenna, having recited many opposing opinions concerning *succaram*, coincides in his words with Dioscorides, reciting the same discourse on *conion*. Concerning which indeed Haly Abbas says in his second book of practice: *Succaram* is a sleeping, lethal [substance] from coldness; if anyone takes a small amount of it in wine, it induces sleep. Some also say that *succaram* is a species of henbane, just as was said concerning *conium*. Whatever it may be, it appears cold and poisonous. Concerning which, see Peter of Abano original: "petrum aponēſem" in his third book on phlegm, and in the *Conciliator*, question 150. Likewise, concerning hemlock, see the same in question 149, for Constantine places it as hot and dry in the third degree. Similarly, Averroes collects this in book three. Aponensis, however, says that terrestrial hemlock is hot and dry; of that opinion were Constantine and the author of *Circa Instans* a medieval medical text. Democritus estimated hemlock to be a type of henbane and places it as cold. Aquatic hemlock is undoubtedly poisonous and pestilential, which Aponensis thinks kills by maximum cold and heat.

¶ The fourth doubt in Avicenna concerning the nature of Coriander.

Avicenna says of coriander that it is cold and dry. Galen, however, Hippocrates, Isaac, and Averroes, in the fifth book, place it as hot, composed of contrary substances: that is, of a bitter substance, an aqueous substance, and a styptic one; and according to this, it performs diverse operations. And thus Averroes holds with Salerno and Isaac against Avicenna. The property of coriander is to prohibit vapors from the head, and for this reason, it is placed in the food of a patient suffering from epilepsy from vapors of the stomach, and it also aids vertigo caused by choleric and phlegmatic vapors. However, the eating of much of it generates darkness of vision, aids the tremors of the heart, is of slow digestion for one who is hot, and comforts a stomach that has been cooled, and it settles dry eructation after a meal. Some of the newer authors dose coriander from 6 to 10 grains, but I have not read this in a famous author.

¶ The fifth doubt of Avicenna concerning saphati and its remedies.

Avicenna uses the same remedies for saphati a type of skin disease, often translated as tinea or scaly eruption as Paul of Aegina does for lichen or impetigo: namely, the dung of a lizard and the dung of thrushes, specifically those eating rice. Because Paul names those birds eating rice not as thrushes, but rather as starlings, concerning which the error of the Arabs, and especially Avicenna, who often puts thrushes for starlings, we have spoken above. That Avicenna also uses saphati for ringworm original: "tinea", not only dry, as Rhazes sometimes [does], but also humid: namely with tucia zinc oxide, climia a metallic ore, and chimolea a type of clay/powder, burnt paper with vinegar, and pine gum with pomegranate flowers original: "balaustiis", and vinegar and rose oil. For Paul of Aegina applies almost all of these to saut a type of moist ringworm, that is, a certain species of moist ringworm, so named in the treatment. In Avicenna, all species of saphati are ailments of the skin of the head. For the beginning of saphati, which is (as Avicenna says) small, fixed, light pustules original: "bothoz", divided in the enumeration of the places, and then ulcerating, are nothing other than exanthemata eruptions, that is, pustules, which Paul writes are of a reddish color and roughen the top part of the head, causing them to ulcerate. Sirengi, however, which is a species of moist saphati in Avicenna, is fauus favus, a fungal infection among the Greeks, to which (as we have said) Avicenna writes the same remedies that Paul does for sirengi. What is in Avicenna is depraved, just as perhaps in balciati, or as others write, Raciati, another species of saphati. They are, however, as Paul and Alexander explain, pustules rising above the skin of the head.

¶ The sixth doubt concerning many corrupted names of herbs in Avicenna.

In the second volume of Avicenna, chochium is written for phoca, that is, a sea calf. Cheiche for caucamo a fragrant gum, the same for a certain fragrant gum. Astraficus for asteratticus, that is, the herb inguinaria an herb for the groin; baesthe for becio, that is, coltsfoot; bilonium for pelio; beblili for peplo, herbs of the same powers. The former, however, to garden purslane, the latter to rue, which are similar; quequero for cenchro, that is, millet; sucutum for symphito, that is, the herb comfrey original: "consolida". Tesifie for thapsia a medicinal plant; and a thousand other corruptions of Greek words are found, which I think can scarcely be understood without the Greek authors who delivered medicine to posterity, when Avicenna, such a great physician and teacher of medicine, sometimes blinds himself in them; so that he explains tesifie, that is, the gum of wild rue, which is nowhere found. Scutum is indeed houseleek, or a species of mandrake seed according to two opinions, both of which, however, he interprets falsely. Concerning this obscurity of names, I do not know what could be more dangerous in the work of medicine, when from it, it happens that not only is one disease treated for another, but also other remedies are exhibited for others. Wherefore, Alexander Benedetti of Verona, most loving to our [cause], and Nicolaus Leonicenus of Vicenza, men of no less genius and doctrine, could never be praised enough, who by their own industry take care to print all the wisdom of the Greeks, philosophy, oratory, and medicine in numerous volumes.

¶ The seventh doubt concerning Altoim and bubo.

That Avicenna wished in the fourth book, where he writes concerning altois, to deal with this tumor that arises especially in the groins, will be easily conjectured by anyone who compares the words of Avicenna concerning Altoim and Paul concerning bubo. For there are almost the same medicines with which Avicenna treats Altoim and Paul treats bubo, except that Paul distinguished the same treatment much more correctly. For since there is a double bubo swollen lymph node: one which is made from a primitive cause (to use a word common among the younger physicians) and therefore from blood not...