GALEN'S PHYSIOLOGY.

97

lospiral, median, and ulnar nerves, and the brachial vessels, owing to his ignorance of their position. The operator, says Galen, was so terrified that he only ligatured the vessels, and the partially-paralysed patient avenged himself by following the surgeon in the streets calling after him: "You cut my nerves".

Galen's physiology, though somewhat spoilt by excessive theorising, was no less admirable. He proved by experiment the falsity of Erasistratus' doctrine that the arteries contain air only, though at the same time he hindered the discovery of the circulation by three erroneous statements— (1) that the veins originate from the liver; (2) that the most important motion of the heart is its diastole, and (3) that the septum between the ventricles is permeable. In opposition to his predecessors, he declared that respiration serves not only to cool the body, but to maintain the animal heat, and made the happy suggestion that when we discover what part of the atmosphere supports combustion we shall also know what is the source of the bodily temperature. His comparison of sound to a wave-like movement was equally fortunate.

But Galen's chief physiological work was his investigation of the nervous system, in which he made extensive use of vivisections. He distinguished sensory, motor, and mixed nerve trunks, traced the connection between the vagus and the sympathetic, showed the importance of the recurrent nerves for the production of voice, and, above all, pointed out that the nerves have no power in themselves, but merely conduct impulses to and from the brain and spinal cord. This knowledge gained him a victory over the hated Methodists. Pausanias, a celebrated sophist, had complained of loss of sensation in the fourth and fifth fingers of his left hand, and the Methodist physicians who attended him, considering the disease to be due to "constriction," applied poultices locally, but without effect. Galen was then summoned, and at once recognised the distribution of the ulnar nerve. On inquiry he found that the sophist had been

thrown from his chariot some time before and had struck his back against a stone. He thereupon applied counterirritants to the region of origin of the brachial plexus, and the patient recovered, to the confusion of the Methodists. and the triumph of Galen, who tells the story at least three times in his extant writings.

Medicine, according to Galen, rests upon anatomy and physiology, and is the art of maintaining and restoring health. Disease is the opposite of health, and, taking the simplest of his many definitions, is "an abnormal affection of the body giving rise to a lesion of function”. He further divides diseases into three classes (1) those affecting the "similar parts," or simple tissues, muscle, nerve, ligaments, etc.; (2) those of the compound tissues, or organs, heart, lungs, etc.; (3) those affecting the body generally, and, especially, the four humours. Diseases of this last class are "dyscrasiæ," and contrast with the complete and harmonious mixture of the humours "eucrasia". But this state of ideal health rarely occurs, and the predominance of the various humours gives rise to the "temperaments," sanguine, phlegmatic, bilious, or melancholic, which, though partaking of the nature of disease, are not actually to be so called unless they produce a perversion of function.

66

The causes of disease are also divided by Galen into three classes (1) procatarctic (primitive or exciting); (2) pro-egumenic (antecedent or predisposing), and (3) synectic (conjunct or proximate). Of these the first are external and include mechanical injuries, and abnormalities in what came to be called the six non-naturals" or things not innate, viz., air, food and drink, rest and exercise, sleep and waking, excretions and retentions, and affections of the mind. The other two are internal, the pro-egumenic causes being those morbid states of the body which are antecedent to disease, the synectic those which coincide with it, so that when they are present the disease is also present, and vice versa. Thus, to adopt a more modern nomenclature,

SYMPTOMS.-SIGNS.-INDICATIONS.

99

the exciting cause of an attack of gout may be over-exertion or excess of some kind, the predisposing cause is a morbid state of the humours which may be inherited, and the proximate cause is the actual deposit of morbid matter in the joint. Galen defines symptoms as "morbid affections dependent and necessarily following upon diseases, as the shadow follows the substance," and he distinguishes three forms (1) altered functions (actiones læsæ); (2) vitiated qualities (qualitates vitiate), and (3) the result of both of these especially morbid excretions and retentions. Signs are those symptoms which show either what the disease is (diagnostic or pathognomic signs), or how it will end (prognostic signs). We must admit that these definitions show considerable acumen, and in their broader outlines they correspond with those still accepted, but he so delighted in defining and classifying, and carried out those processes with such subtlety and minuteness that he defeated his own purpose, and diverted the minds of generations of disciples from the more practical part of his teaching.

Our short remaining space will be devoted to his therapeutic doctrines, which display at once the best and worst sides of the dogmatic school. As an example of the former, we may take his doctrine of the "indications," under which term he comprises "whatever enables us to draw conclusions as to treatment apart from experience". The indications formed the touchstone of distinction between the three great medical sects. The Empirics rejected them entirely, for them experience was the only rule of treatment; the Methodists reduced them to one only—the restoration of the normal state of the pores by the use of contraries; while to the Dogmatists they formed the basis of all rational treatment. The first and greatest indication is to remove the cause of the disease or to prevent its action; a second class arises from the symptoms, any of which may form ground for treatment—if against Nature, by contraries, if in accordance with Nature, by similars. Other sources of indications are the temperament of the patient, the season

of the year and external circumstances generally, and, finally, as Galen curiously adds, the patient's dreams.

His teaching as to the action of drugs was less excellent, but unfortunately far more influential. He held that some, such as emetics, purgatives, poisons and their antidotes, act through their whole substance, and are, in a sense, specifics, a doctrine consonant with the older dogmatic theory of the specific action of purgatives, which still survives in the modern terms hydragogue and cholagogue. But most drugs act, according to Galen, through one of the elementary qualities-heat, cold, dryness, and moisture, which they possess not in an actual but a potential form, each quality being further divisible into four degrees, according to its intensity. Thus pepper and opium are (potentially) hot and cold respectively in the fourth degree. This theory, after being developed to an absurd extent by the mediaval physicians, has happily vanished, leaving us only the terms "actual" and "potential" as applied to cauteries.

It is a curious fact that the treatise On Ancient Medicine, in which Hippocrates mentions this doctrine and rejects it, is the only one of his genuine works on which Galen has not written a commentary, probably because he felt he could not reconcile it with his own teaching.

NOTE.

The most convenient edition of Galen is that of Kühn, 22 vols., Lips., 1821-33. The two " cases "above related may be found in the treatises De Anat. Admin., iii. 9 (K., ii. 395), and De Locis Affectis, i. 5 (K., viii. 56). See also Gasquet, "The Practical Medicine of Galen and his Time," Med.-Chir. Review, 1867, ii.; Falk, Galens Lehre vom Nervensysteme, Leipsic, 1871.

XX.-GALEN AND HIPPOCRATES COMPARED. WHEN Marcus Aurelius returned from his first campaign. against the Germans, A.D. 175, he was doubtless welcomed

AN IMPERIAL PATIENT.

ΙΟΙ

with festivities, and we may suppose that even the philosophic emperor fared more sumptuously in the palace than in the camp. At any rate, shortly after his return we find him taking, in addition to his usual morning pill of theriac, a dose of bitter aloes, the "hiera picra " of Galen. In spite of this his disorder so increased that, on the following evening, a message was sent to Galen requesting him to sleep at the palace. Hardly had he got there when a slave came in, lighted the lamps, and summoned him to the emperor's bedroom. Here he found three army surgeons feeling his pulse, who said that he was in the early stage of a feverish attack. The emperor asked Galen for his opinion, but he replied that those who had been with him during the campaign would be the best judges. "However on special command I felt his pulse, and finding it quite normal, considering his age and the time of day, I declared it was no fever but a digestive disorder, due to the food he had eaten, which must be converted into phlegm before being excreted. Then the emperor repeated three times, That's the very thing,' and asked what was to be done. I answered that I usually gave a glass of wine, with pepper sprinkled on it, 'but for you kings we only use the safest remedies and it will suffice to apply wool soaked in hot nard ointment locally'. The emperor ordered the wool, wine, etc., to be brought, and I left the room. His feet were warmed by rubbing with hot hands, and after drinking the peppered wine, he said to Pitholaus (his son's tutor), We have only one doctor and that an honest one,' and went on to describe me as the first of physicians, and the only philosopher, for he had tried many before who were not only lovers of money, but also contentious, ambitious, envious and malignant."

6

The above (which is slightly abridged from the De Prenotione ad Posthumum, cap. xi.) is interesting both in itself and as affording an example of Galen's idea of a clinical history. Though he has written commentaries on each of the forty-two cases so well described by Hippocrates, it seems to have never occurred to him that they were worth