Galen’s account of the Empirics.
Normally, however, Galen upholds both reason and experience as criteria of truth against the opposing schools of Dogmatics and Empirics. The former attacked experience as uncertain and impossible to regulate, slow and unmethodical. The latter replied that experience was consistent, adaptable to art, and proof enough.[688]Galen’s chief objection to the Empirics is that they reject reason as a criterion of truth and wish the medical art to be irrational.[689]“The Empirics say that all things are discovered by experience, but we say that some are found by experience and some by reason.”[690]Galen also objects to Herodotus’s explanation of the medical art as originating in the conversation of patients exposed at crossroads who told one another of their complaints and recoveries and thus evolved a fund of common experience.[691]Galen criticizes such experience as irrational and not yet put into scientific form (οὔπω λογική). Of the Empirics he tells us further that they regard phenomena only and ignore causes and put no trust in reasoning. They hold that there is no system or necessary order in medical discovery or doctrine, and that some remedies have been discovered by dreams, others by chance. They also accepted written accounts of past experiences and thus to a certain extent trusted in tradition. Galen argues that they should test these statements of past authorities by reason.[692]His further contention that, if they test them by experience, they might as well reject all writings and trust only to present experience from the start, is a sophistical quibble unworthy of him. He adds, however, that the Empirics themselves say that past tradition or “history” (ἱστορία) should not be judged by experience, but it is unlikely that he represents their view correctly in this particular. In another passage[693]he says that they distinguish three kinds of experience, chance or accidental, offhand or impromptu, and imitative or the repetition of the same thing. In a third passage[694]he repeats that they held that observation of one or two instances was not enough, but that oft-repeated observation was needed with all conditions the same each time. In yet another place[695]he says that the Empirics observe coincidences in things joined by experience. He himself defines experience as the comprehending and remembering of something seen often and in the same condition,[696]and makes the good point that one cannot observe satisfactorily without use of reason.[697]He also admitsin one place that some Empirics are ready to employ reason as well as experience.[698]
How the Empirics might have criticized Galen.
Having noted Galen’s criticism of the Empirics, we may imagine what their attitude would be towards his medicine. They would probably reject all his theories—which we, too, have finally discarded—of four elements and four qualities and the like, and would accept only his specific recommendations for the cure of disease based upon his medical experience; except that they would also be credulous concerning anything which he assured them was based upon his own or another’s experience, whether it truly was or not. They would, however, have probably questioned much of his anatomical inference from the dissection of the lower animals, since he tells us that they “have written whole books against anatomy.”[699]Considering the state of knowledge in their time, their refusal to attempt any large generalizations or to hazard any scientific hypotheses or to build any risky medical system was in a way commendable, but their credulity as to particulars was a weakness.
Galen’s standard of reason and experience.
On the whole Galen’s attitude towards experience seems an improvement upon theirs. He was apparently more critical towards the “experiences” of past writers than the average Empiric, and in his combination of reason and experience he came a little nearer to modern experimental method. Reason alone, he says, discovers some things, experience alone discovers some, but to find others requires use of both experience and reason.[700]In his treatise upon critical days he keeps reiterating that their existence is proved both by reason and experience. These two instruments in judging things given us by nature supplement each other.[701]“Logical methods have force in finding what is sought, but in believing what has been well found there are two criteria for all men, reason and experience.”[702]“What can you do with men who cannot be persuaded either by reason or bypractice?”[703]Galen also speaks of discovering a truth by logic and being thereby encouraged to try it in practice and of then verifying it by experience.[704]This, however, is not quite the same thing as saying that the scientist should aim to discover new truth by purposive experiments, or that from a number of experiences reason may infer some general law of nature.
Simples knowable only from experience.
It is perhaps in his work on medicinal simples that Galen lays most stress upon the importance of experience. Indeed he sees no other way to learn the properties of natural objects than through the experience of the senses.[705]“For by the gods,” he exclaims, “how is it that we know that fire is hot? Are we taught it by some syllogism or persuaded of it by some demonstration? And how do we learn that ice is cold except from the senses?”[706]And Galen sees no advantage in spending further time in arguments and hair-splitting where one can learn the truth at once from the senses. This thought he keeps repeating through the treatise, saying, for example, “The surest judge of all will be experience alone, and those who abandon it and reason on any other basis not only are deceived but destroy the value of the treatise.”[707]Moreover, he restricts his account of medicinal simples to those with which he is personally acquainted. In the three books treating of plants he does not mention all those found in all parts of the world, but only as many as it has been his privilege to know by experience.[708]He proposes to follow the same rule in the ensuing discussion of animals and to say nothing of virtues which he has not tested or of substances mentioned in the writings of past physicians but unknown to him. He dares not trust their statements when he reflects how some have lied in such matters. In the middle ages Albertus Magnus talks in much the same strain in his works on animals, plants, and minerals, and perhaps he was stimulated to such ideals, consciously or unconsciously, directly by reading Galen or indirectly through Arabic works, by Galen’s earlier expression of them. Galen mentions some virtues ascribed to substances which he has tested by experience and found false, such as the medicinal properties attributed to the belly of a seagull[709]and some of those claimed for the marine animal called torpedo.[710]Anointing the place with frog’s blood or dog’s milk will not prevent eyebrows that have been plucked out from growing again, nor will bat’s blood and viper’s fat remove hair from the arm-pits.[711]Also the brain of a hare is only fairly good for boys’ teeth.[712]
Experience and food science.
In beginning his work on food values[713]Galen states that many have discussed the properties of aliments, some on the basis of reason alone, some on the basis of experience alone, but that their statements do not agree. On the whole, since reasoning is not easy for everyone, requiring natural sagacity and training from childhood, he thinks it better to start from experience, especially since not a few physicians are of the opinion that only thus can the properties of foods be learned.
Experience and compounds.
The Empirics contended that most compound medicines had been hit upon by chance, and Galen grants that the Dogmatics usually are unable to give reasons for the ingredients of their doses and find difficulty in reproducing a lost prescription.[714]But he holds that reasons can be given for the constituents of the compound and that the logical discovery of such remedies differs from the empirical.[715]His own method was to learn the nature of each disease and the varied properties of simples, and then prepare a compound suited to the disease and to the patient.[716]On the other hand, we see how much depends upon experience from his confession that sometimes he has hastily prepared a compound from a few simples, sometimes from more, sometimes from a great variety. If the compound worked well, he wouldcontinue to use it, sometimes making it stronger and sometimes weaker.[717]For as you cannot put together compounds without rational method, so you cannot tell their strength certainly and accurately without experience.[718]He admits that no one can tell the exact quantity of each ingredient to employ without the aid of experience,[719]and says, “The proper proportions in the mixture we shall find conjecturally before experience, scientifically after experience.”[720]In these treatises upon compound medicines, unlike that on medicinal simples, Galen gives the prescriptions of former physicians as well as some tested by his own experience.[721]Sometimes, however, he expresses a preference for the medicines of those writers who were “most experienced”; and once says that he will give some compounds of the more recent writers, who in their turn had selected the best from older writers of long experience and added later discoveries.[722]We suspect, however, that some of these prescriptions had not been tested for centuries.
Suggestions of experimental method.
Galen gives a few directions how to regulate medical observation and experience, although they cannot be said to carry us very far on the road to modern laboratory research. He saw the value of “long experience,” a phrase which he often employs.[723]He states that one experience is enough to learn how to prepare a drug, but to learn to know the best medicines in each kind and in different places many experiences are required.[724]Medicinal simples should be frequently inspected, “since the knowledge of things perceived by the senses is strengthened by careful examination.”[725]Galen advises the student of medicine to study herbs, trees, and fruit as they grow, to find out when it is best to pluck them, how to preserve them, and so on. But elsewhere he states that it is possible to estimate the general virtue of the simplefrom one or two experiences.[726]However, he suggests that their effect be noted in the three cases of a perfectly healthy person, a slightly ailing patient, and a really sick man.[727]In the last case one should further note their varying effects as the disease is marked by any excess of heat, cold, dryness, or moisture. Care should be taken that the simples themselves are pure and free from any admixture of a foreign substance.[728]“It is also essential to test the relation to the nature of the patient of all those things of which great use is made in the medical art.”[729]One condition to be observed in experimental investigation of critical days is to count no cases where any slip has been made by physician or patient or bystanders or where any other foreign factor has done harm.[730]Galen was acquainted with physical experiments in siphoning, for he says that, if one withdraws the air from a vessel containing sand and water, the sand will follow before the water, which is the heavier (sic?).[731]
Difficulty of medical experiment.
Galen also points out some of the difficulties of medical experimentation. One is the extreme unlikelihood of ever being able to observe in even two cases the same combination of symptoms and circumstances.[732]The other is the danger to the life of the patient from rash experimenting.[733]Thus Galen more than once tells us of abstaining from testing some remedy because he had others of whose effects he was surer.
Empirical remedies.
In the treatise on easily procurable remedies ascribed to Galen,[734]in which we have already seen evidence of later interpolation or authorship, some recipes are concluded bysuch expressions as, “This has been experienced; it works unceasingly,”[735]or “Another remedy tested by us in many cases.”[736]This became a custom in many subsequent medical works, including those of the middle ages. One recipe is introduced by the caution, “But don’t cure anybody unless you have been paid first, for this has been tested in many cases.”[737]But we are left in some doubt whether we should infer that remedies tested by experience are so superior that they call for cash payment rather than credit, or so uncertain that it is advisable that the physician secure his fee before the outcome is known. In the middle ages the wordexperimentumwas used a great deal as a synonym for any medical treatment, recipe, or prescription. Galen approaches this usage, which we have already noticed in Pliny’sNatural History, when he describes “a very important experiment” in bleeding performed by certain doctors at Rome.[738]
Galen’s influence upon medieval experiment.
Indeed Galen appears to have exerted a great influence in the middle ages by his passages concerning experience in particular as well as by his medicine in general. Medieval writers cite him as an authority for the recognition of experience and reason as criteria of truth.[739]Gilbert of England cites “experiences from the book of experiments experienced by Galen,”[740]and we shall find more than one such apocryphal work ascribed to Galen in the middle ages. John of St. Amand seems to have developed seven rules[741]which he gives for discovering experimentally the properties of medicinal simples from what we have heard Galen say on the subject, and in another work, theConcordances, John collects a number of passages about experience fromthe works of Galen.[742]Peter of Spain, who died as Pope John XXI in 1277, cites Galen in his discussion of “the way of experience” and “the way of reason” in hisCommentaries on Isaac on Diets.[743]We have already suggested Galen’s possible influence upon Albertus Magnus, and we might add Roger Bacon who wrote some treatises on medicine. But it is hardly possible to tell whether such ideas were in the air, or were due to Galen individually either in their origin or their transmission. But he made a rather close approach to the medieval attitude in his equal regard for logic and for experimentation.
His more general medieval influence.
The more general influence of Galen upon all sides of the medicine of the following fifteen centuries has often been stated in sweeping terms, but is difficult to exaggerate. His general theories, his particular cures, his occasional marvelous stories, were often repeated or paraphrased. Oribasius has been called “the ape of Galen,” and we shall see that the epithet might with equal reason be applied to Aëtius of Amida. Indeed, as in the case of Pliny, we shall find plenty of instances of Galen’s influence in our later chapters. Perhaps as good a single instance of medieval study of Galen as could be given is from theConcordancesof John of St. Amand already mentioned, which bear the alternative title, “Recalled to Mind” (Revocativum memoriae), since they were written to “relieve from toil and worry scholars who often spend sleepless nights in searching for points in the books of Galen.”[744]Or we may note how the associates of the twelfth century translator from the Arabic, Gerard of Cremona, added a list of his works at the close of his translation of Galen’sTegni, “imitating Galen in the commemoration of his books at the end of the same treatise,” as they themselves state.[745]
Not that medieval men did not make additions of theirown to Galen. For instance, the noted Jewish philosopher, Moses Maimonides, in adding his collection of medicalAphorismsto the many previous compilations of this sort by Hippocrates, Rasis (Muhammad ibn Zakariya), Mesuë (Yuhanna ibn Masawaih), and others, states that he has drawn them mainly from the works of Galen, but that he supplements these with some in his own name and some by other “moderns.”[746]Not that Galen was not sometimes criticized or questioned. A later Greek writer, Symeon Seth, ventured to devote a special treatise to a refutation of some of Galen’s physiological views. In it, addressing himself to those “persons who regard you, O Galen, as a god,” he endeavored to make them realize that no human being is infallible.[747]Among the medical treatises of Gentile da Foligno, who was papal physician and performed a public dissection at Padua in 1341,[748]is found a brief argument against Galen’s fifth aphorism.[749]But such criticism or oppositiononly shows how generally Galen was accepted as an authority.
From Galen’s habits of critical estimation rather than blind acceptation of authority, of scientific observation, careful measurement, and personal experiment, from his brilliant demonstrations by dissection, and his medical prognostication and therapeutics, sane and shrewd for his time,—from these we have now to turn to the other side of the picture, and examine what information his works afford us concerning the magic and astrology in ancient medicine, concerning the belief in occult virtues, suspensions, characters, incantations, and the like. We may first consider what he has to say concerning magic and divination as he understands those words, and then take up his attitude to those other matters which we look upon as almost equally deserving classification under those heads.
Accusations of magic against Galen.
Apollonius of Tyana and Apuleius of Madaura were not the only celebrated men of learning in the early Roman Empire to be accused of magic; we have already alluded to the charges of magic made against Galen by the envious physicians of Rome during his first residence in that city. It is hard to escape the conviction that at that time learned men were very liable to be suspected or accused of magic. Indeed, Galen makes the general assertion that when a physician prognosticates aright concerning the future course of a malady, this seems so marvelous to most men that they would receive him with great affection, if they did not often regard him as a wizard.[750]Soon after saying this, Galen begins the story of the prognostications he made and the cure he wrought, when all the other doctors took an opposite view of the case.[751]One of them then jealously suggested that Galen’s diagnosis was due to divination.[752]When asked by what kind of divination, he gave different answersat different times and to different persons, sometimes saying by dreams, sometimes by sacrificing, again by symbols, or by astrology. Afterwards such charges against Galen kept multiplying.[753]As a result, Galen says that since then he has not gone about advertising his prognostications like a herald, lest the physicians and philosophers hate him the more and slander him as a wizard and diviner, but that he now reveals his discoveries only to his friends.[754]In another treatise he represents Hippocrates as saying that a proficient doctor should be able to prognosticate the course of diseases, but adds that contemporary physicians call such a doctor a sorcerer and wonder-worker (γόητά τε καὶ παραδοξολόγον).[755]Again in his work on medicinal simples[756]he states that he abstained from testing the supposed virtue of crocodile’s blood in sharpening the vision, and the blood of house mice in removing warts, partly because he had other reliable eye-medicines and cures for warts—such asmyrmecia, a gem with wart-like lumps, partly because by employing such substances he feared to incur the reputation of a sorcerer, since jealous physicians were already slandering his medical prognostications as divination. This last passage affords a good illustration of the close connection with magic of certain natural substances supposed to possess marvelous virtues, while Galen’s wart stone also seems magical to the modern reader.
His charges of magic against others.
Galen himself sometimes calls other physicians magicians. Certain men with whom he does not agree are called by him “liars or wizards or I don’t know what to say,”[757]and another man who used mouse dung to excess he calls superstitious and a sorcerer.[758]In the same work on simples[759]he says that he will list herbs in alphabetical order as Pamphilus did, but that he will not like him descend to old wives’ tales, Egyptian sorceries and incantations, amulets and other magical devices, which not only do not belong in the medical artbut are utterly false. Pamphilus never saw most of the herbs he mentioned, much less tested their virtues, but copied anything he found, piling up names, incantations, and wizardry. Galen accuses Xenocrates Aphrodisiensis also of not having eschewed sorcery, and he notes that medical writers have either said nothing about sweat or what is superstitious and bordering upon magic.[760]
Charms and wonder-workers.
Philters, love-charms, dream-draughts, and imprecations Galen regards as impossible or injurious, and intends to have nothing to do with them. He thinks it ridiculous to believe that by such spells one can bewitch one’s adversaries so that they cannot plead in court, or conceive or bear children. He considers it worse to advertise and perpetuate such false or criminal notions in writings than to practice such a crime but once.[761]In one passage,[762]however, to illustrate his theory that the gods prepare the sperms of plants and animals, and set them going as it were, and afterwards leave them to themselves, Galen compares them to the wonder-workers—who were perhaps not magicians but men similar to our sidewalk fakirs who exhibit mechanical toys—who start things moving and then go away themselves while what they have prepared moves on artificially for a time.
Animal substance inadmissible in medicine.
Galen’s own works are not entirely free from the magical devices of which he accuses others. We may begin with animal substances, since he himself has testified that the use of sweat, crocodile’s blood, and mouse’s dung is suggestive of magic. Moreover, he attributes more bizarre virtues to the parts of animals than to herbs or stones. In a passage somewhat similar to that in which Pliny[763]expressed his horror at the use of human blood, entrails, and skulls as medicines, Galen declares that he will not mention the abominable and detestable, as Xenocrates and some others have done. The Roman law has long forbidden eating human flesh, while Galen regards even the mention of certain secretions and excrements of the human body asoffensive to modest ears.[764]Nevertheless, before long he offends against his own standard and describes how he administered to patients the very substance which he had before characterized as most unmentionable.[765]It may also be noted that he repeats unquestioningly such a tale as that the cubs of the bear are born unformed and licked into shape by their mother.[766]
Nastiness of ancient medicine.
Further milder illustrations of the fact that such nasty substances were then not merely recommended in books but freely employed in actual medical practice, are seen in the frequent use by one of Galen’s teachers of the dung of dogs who for two days before had eaten nothing but bones,[767]in Galen’s own wonderfully successful treatment of a tumor on a rustic’s knee with goat dung—which is, however, too sharp for the skins of children or city ladies,[768]and in his discovery by repeated experience that the dung of doves who take little exercise is less potent than that of those who take much,[769]Galen also says that he has known of doctors who have cured many persons by giving them burnt human bones in drink without their knowledge.[770]
Parts of animals.
Galen’s medicinal simples include the bile of bulls, hyenas, cocks, partridges, and other animals.[771]A digestive oil can be manufactured by cooking foxes and hyenas, some alive and some dead, whole in oil.[772]Galen discusses with perfect seriousness the relative strength of various animal fats, those of the goose, hen, hyena, goat, pig, and so forth.[773]He decides that lion’s fat is by far the most potent, with that of the pard next. Among his simples are also found the slough of a snake, a sheepskin, the lichens of horses, a spider’s web,[774]and burnt young swallows, for whose introduction into medicine he gives Asclepiades credit.[775]OfArchigenes’ prescriptions for toothache he repeats that which recommended holding for some time in the mouth a frog boiled in water and vinegar, or a dog’s tooth, burnt, pulverized, and boiled in vinegar.[776]Cavities may be filled with toasted earthworms or spiders’ eggs diluted with unguent of nard. Teething infants are benefited, if their gums are moistened with dog’s milk or anointed with hare’s brains.[777]For colic he recommends dried cicadas with three, five, or seven grains of pepper.[778]
Some scepticism.
Galen is less confident as to the efficacy for earache of the multipedes which roll themselves up into a ball, and which, cooked in oil, are employed especially by rural doctors.[779]He is still more sceptical whether the liver of a mad dog will cure its bite.[780]Many say so, and he knows of some who have tried it and survived, but they took other remedies too.[781]Galen has heard that some who trusted to it alone died. In one treatise[782]Galen discusses the strange virtues of the basilisk in much the usual way, but in his work on simples[783]he remarks drily that it is obviously impossible to employ it in pharmacy, since, if the tales about it be true, men cannot see it and live or even approach it without danger. He therefore will not include it or elephants or Nile horses (hippopotamuses?) or any other animals of which he has had no personal experience.
Doctrine of occult virtue.
Galen tries to find some satisfactory explanation of the strange properties which he believes exist in so many things. The attractive power of the magnet and of drugs suggests to him that nature in us is divine, as Homer says, and leads like to like and thus shows its divine virtues.[784]Galen rejects Epicurus’s explanation of the magnet’s attractive power.[785]It was that the atoms flowing off from both the magnet and iron fit one another so closely that the two substances are drawn together. Galen objects that this does not explain how a whole series of rings can be suspended in a row from a magnet. Galen’s teacher Pelops, who claimed to be able to tell the cause of everything, explained why ashes of river crabs are used for the bite of a mad dog as follows.[786]The crab is efficacious against hydrophobia because it is an aquatic animal. River crabs are better for this purpose than salt water crabs because salt dries up moisture. He also thought the ashes of crabs very potent in absorbing the venom. But this type of reasoning is unsatisfactory to Galen, who finds the best explanation of all such action in the peculiar property, or occult virtue, of the substance as a whole. Upon this subject[787]he proposes to write a separate treatise, and in the fragmentDe substantia facultatum naturalium(περὶ οὐσίας τῶν φυσικῶν δυνάμεων) he again discusses the matter.[788]
Virtue of the flesh of vipers.
Among parts of animals Galen regarded the flesh of vipers as especially medicinal, particularly as an antidote to poisons. Of the following cures wrought by vipers’ flesh which Galen narrates[789]two were repeated without giving him credit by Aëtius of Amida in the sixth, and Bartholomew of England in the thirteenth century, and doubtless by other writers. When Galen was a youth in Asia, some reapers found a dead viper in their jug of wine and so were afraid to drink any of it. Instead they gave it to a man near by who suffered from the terrible skin disease elephantiasis and whom they thought it would be a mercy to put quietly out of his misery. He drank the wine but instead of dying recovered from his disease. A similarly unexpected cure was effected when a slave wife in Mysia tried to kill her husband by offering him a like drink. A third case was that of a patient whom Galen told of these two previous cures. After resorting to augury to learn if he too should try it and receiving a favorable response, the patient drank wine infected by venom with the result that his elephantiasis changed into leprosy, which Galen cured a little later with the usual drugs. A fourth man, while hunting vipers, was stung by one. Galen bled him, extracted black bile with a drug, and then made him eat the vipers which he had caught and which were prepared in oil like eels. A fifth man, warned by a dream, came from Thrace to Pergamum. Another dream instructed him both to drink, and to anoint himself with, a concoction of vipers. This changed his disease into leprosy which in its turn was cured by drugs which the god prescribed.
Theriac.
The flesh of vipers was an important ingredient in the famous antidote and remedy called theriac, concerning which Galen wrote two special treatises[790]besides discussing it in his works on simples and antidotes. Mithridates, like King Attalus in Galen’s native land, had tested the effects of various drugs upon condemned criminals, and had thus discovered antidotes against spiders, scorpions, sea-hares, aconite, and other poisons. He then combined the results of his research into one grand compound which should be an antidote against any and every poison. But he did not include the flesh of the viper, which was added with some other changes by Andromachus, chief physician to Nero.[791]The divine Marcus Aurelius used to take a dose of theriac daily and it had since come into general use.[792]Galen gives a long list of ills which it will cure, including the plague and hydrophobia,[793]and adds that it is beneficial in keeping a man in good health.[794]He advises its use when traveling or in wintry weather, and tells Piso that it will prolong his life.[795]He explains more than once[796]how to prepare theviper’s flesh, why the head and tail must be cut off, how it is cleaned and boiled until the flesh falls from the backbone, how it is mixed with pounded bread into pills, how the flesh of the viper is best in early summer. Galen also accepts the legend,[797]quoting six lines of verse from Nicander to that effect, that the viper conceives in the mouth and then bites off the male’s head, and that the young viper avenges its father’s death by gnawing its way out of its mother’s vitals. TheMarsiat Rome denied the existence of thedipsasor snake whose bite causes one to die of thirst, but Galen is not quite sure whether to agree with them.
Magical compounds.
Already we have had occasion to refer to Galen’s two works on compound medicines which occupy the better part of two bulky volumes in Kühn’s edition and contain a vast number of prescriptions. It is not uncommon for one of these to contain as many as twenty-five ingredients. It seems unlikely that such elaborate concoctions would have been discovered by chance, as the Empirics held, but the modern reader is ready to agree that it was chance, if anyone was ever cured of anything by one of them. Yet Galen, as we have seen, believes that reasons can be given for the ingredients and would not for a moment admit that they are no better than the messes of witches’ cauldrons. He argues that, if all diseases could be cured by simples, no one would use compounds, but that they are essential for some diseases, especially such as require the simultaneous application of contrary virtues.[798]Also where a simple is too strong or weak, it can be toned up or down to just the right strength in a compound. Plasters and poultices seem always to be compounds. Of panaceas Galen is somewhat more chary, except in the case of theriac; he opines that a medicine which is good for a number of ills cannot be very good for any one of them.[799]