GALENUS, CLAUDIUS. 



GALENUS, CLAUDIUS. 





But in order to form a correct estimate of the merits of this physi- 

 cian, it is necessary for us to mention particularly some of his contri- 

 butions to medical science. Anatomy was at all times the favourite 

 pursuit of Galen, but it does not appear that he had many oppor- 

 tunities of dissecting the humau subject. This we may infer with 

 certainty from the gratification he expresses at having discovered a 

 human skeleton at Alexandria, and having been enabled to make 

 observations on the body of a criminal which had remained without 

 burial. His dissections were principally confined to the apes and 

 lower animals ; and it is to this circumstance that many of the errors 

 in his description are rcferrible ; for from the examination of these 

 animals he attempted to infer analogically the structure of the 

 human body. He describes the sternum as consisting of seven pieces 

 instead of eight. He supposes the sacrum to consist of three pieces 

 instead of five, and looks upon the coccyx as a fourth, whereas it is 

 a distinct bone in men till twenty or twenty-five, and in women as lute 

 as forty-five. 



His descriptions of the muscles appear to be more generally correct. 

 Ho described for the first time two of the muscles of the jaws, and 

 two which move the shoulder. In addition to these he discovered the 

 popliteal muscles and the platysma niyoiJes. He denied the muscular 

 texture of the heart on account of the complicated nature of its 

 functions, but he gave a good description of its transverse fibres and 

 its general structure. The knowledge of the vascular system which 

 Galen possessed does not appear to have been greater or more accurate 

 than that of his predecessors. He supposed the veins to originate in 

 the liver, and the arteries to take their rise from the heart. He like- 

 wise showed by experiment, in opposition to Erasistratus, that the 

 arteries contained blood, and not merely the animal spirits, as that 

 physician maintained. He had observed the structure and use of the 

 valves of the heart, and, arguing from their evident intention, con- 

 cluded that a portion of the blood passed with the animal spirits from 

 the pulmonary artery iuto the pulmonary vein, and so to the left side 

 of the heart. He was also aware of the connection between the veius 

 and arteries by means of the capillary vessels. The existence of the 

 ductus arleriosus and foramen ovale during the stage of foetal life was 

 not unknown to him, and he had also noticed the changes which they 

 undergo after birth. 



Galen understood generally the distinction between nerves of 

 sensation and nerves of motion ; but his knowledge upon this point 

 does not appear to have been great, for he supposed that the former 

 proceeded only from the brain, and that the latter had their origin 

 exclusively in the spinal marrow. This opinion is the more remark- 

 able, as he himself describes the third pair of cerebral nerves, or 

 principal motor nerve of the eye. In his description of the cerebral 

 nerves he notices the olfactory, though somewhat indistinctly, the 

 optic, the third pair, two branches of the fifth, the two divisions of 

 the seventh pair, and some branches of the par vagum and hypoglosaal 

 nerves ; but be appears to have confounded these together very much 

 in his description. He detected the mistake of those anatomists who 

 thought there was an entire crossing of the optic nerves, but fell 

 himself iuto the error of supposing that no decussation at all takes 

 place. 



In order to form correct physiological views, it is necessary to 

 employ many and varied experiments, and to modify them in different 

 ways, that we may be able to satisfy the numerous conditions which 

 every problem in physiology presents. To this mode of inquiry 

 Galen sometimes had recourse, and it were to be wished that he 

 had more frequently made use of it. To prove the dependence of 

 muscular motion upon nervous influence, ha divided tho nerves which 

 supply the muscles of the shoulder, and found that after the division 

 all power of motion ceas- d. But he does not seem to have noticed 

 that the nervous influence is only one of the many stimuli which call 

 the muscles into action. As he considered the heart to be devoid of 

 nerves, he might have avoided ihis error, had he not fortified himself 

 against the truth by assuming that its btructure is not muscular. He 

 also deprived animals of their voice by dividing the intercostal mus- 

 cles, by tying the recurrent nerve, or by injuring ti e spinal cord. 

 In theoretical physiology his arrangement of the vital phenomena 

 deserve* to be particularly recorded, as it forms the groundwork of 

 all the classifications which have since been proposed. It is founded 

 upon the essential differences observed in the functions themselves. 

 Observing that some of them cannot be interrupted without the 

 destruction of life, and for the moat part are unconsciously performed, 

 whilst another class may be suspended without injury, are accom- 

 panied by sensation, and subject to the power of the will, he divided 

 the functions into three great classes. The vital functions are those 

 whose continuance is essential to life ; the animal are tho.-e which are 

 perceived, and for the most part are subject to the will ; whilst the 

 natural are -performed without consciousness or control. He then 

 assumed certain abstract principles upon which these functions were 

 tuppueed to depend. He conceived the first to have their seat in the 

 heart, the second in the brain, and the third in the liver. Thus the 

 pulsations of the h art are produced by the vital forces, and these are 

 communicated to the arteries by the intervention of the pneuma; 

 thin is the more subtle port of the air, which is taken in by respiration, 

 and conveyed from the lungs to the left Bide of the heart, and thence 

 to the different parta of the body. In the brain the pneuma forms 



the medium by which impressions from external objects are conveyed 

 to the common sensorium. The same principle is applied to tho 

 explanation of the natural functions also. Observing that these forces 

 are not sufficient for the explanation of the different vital phenomeua, 

 Galen had recourse to the doctrine of elements, of which, after tho 

 example of Aristotle, and before him Plato in the ' Timjeus," he admits 

 four, and from the mixture of these deduces the secondary qualities. 

 It may be worth while to observe how he employs this hypothesis in 

 his treatise ' De tuenda Valetudine' (Ed. Johan. Caii, Basil, ap. Froben. 

 1549), in the explanation of the phenomena of health and disease. 

 Tho injurious influences to which animal bodies are liable are of two 

 kinds : innate or necessary, and acquired. The former depend upon 

 their original constitution. They are formed of two substances : the 

 blood, which is the material (v\ifj ; aud the semen, the formative 

 principle. These are composed of the same general elements " hot, 

 cold, moist, and dry, four champions fierce," or, to express them iu 

 their essences instead of their qualities, fire, air, water, and earth. 

 Their differences depend upon the proportions in which these elements 

 enter into their compositiou. Thus in the semen the fiery and aeriform 

 essences predominate ; in the blood, the watery aud earthy ; aud in 

 the blood the hot is superior to the cold, and the moist to dry. The 

 semen again is drier than the blood, but yet upon the whole is of a 

 ruoist nature ; so that in the original formation of the body tliere is a 

 predominance of the moist principle. After birth therefore there is 

 a necessity for an increase of the dry principle. This is obtained not 

 from the earth itself, but through the medium of fire. From the 

 increasing influence of this principle, the changes which take place 

 in the body during life are to ba explained : as, for instance, the soft- 

 ness and flexibility of the limbs in childhood compared with their 

 rigidity in old age. By eating and drinking we obtain a fresh supply 

 of the dry and moist principles. By respiration and the pulsations of 

 the heart a due supply of the cold and hot principles is kept up ; but 

 aa they cannot be obtained in a fit state for the different uses of the 

 animal economy, organs are necessary to digest, separate, and remove 

 the unsuitable portions. 



Health consists iu the perfect and harmonious admixture of these 

 various elements ; but w<s must assume, iu addition, that the body is 

 free from pain, aud that there is no obstacle to the due performance of 

 the functions. From this idea of health we may easily form the con- 

 ception of disease. It is that state of body in which the functions are 

 iu any way interrupted. It depends upon some disproportion in the 

 constituent elements, or some unnatural condition of the organs. The 

 causes of disease are divided by Galen into occasional and predisposing. 

 The predisposing causes are supposed to depend upon some degene- 

 ration of the humours. This degeneration was called by him a putre- 

 faction. Thus the quotidian fever is referred to putrefaction of the 

 mucus; tertian, to that of the yellow bile; and quartan, to that of 

 the black bile this last humour being slow of motion, aud requiring 

 a greater time for the completion of the paroxysm. It was upon this 

 theory of the putrefaction of th-j humours that the practice of 

 physicians was founded for centuries after the death of Galen, and 

 their remedies were directed to the expulsion of the supposed offending 

 matter. Inflammation depends, according to Galen, upon the passage 

 of the blood into those parts which in their normal condition do not 

 contain it. If the blood be accompanied by the spirits, the inflam- 

 mation is spirituous ; if the blood penetrates alone, it is phlegrnonous. 

 Erysipelatous inflammation is caused by the admixture of bile; 

 oodematous, by that of mucus ; and schirrous, by the addition of black 

 bile. The same divisions of inflammation are still retained by syste- 

 matic writers, but we are content to abstain from referring them to 

 these assumed causes. 



The reputation of G^eii was established upon the general reception 

 which his theories met with, and his passion for theorising was so 

 great that he has left us but few good descriptions of disease. In these 

 his principal object seems to have been to display his own talent for 

 prognosis. From a character like this we are not to expect much 

 information in the application of particular remedies, but the general 

 principles which he lays down in respect to indications of treatment 

 are worthy of notice. He directs us to draw our indications especially 

 from the nature of the disease ; but if this be undiscovered, from the 

 influence of the seasons and the state of the atmosphere, from tho 

 constitution of the patient, his manner of living, or his strength, and 

 in some few instauces from the accession of the disease. He is said 

 to have occasionally performed surgical operations, but during his 

 stay in Rome he commonly refused to do so, in compliance with tho 

 custom of the Roman physicians. 



The unbounded influence which the authority of this great anil 

 learned physician exercised over the minds of his successors, unques- 

 tionably contributed to retard the progress of medicine ; for while 

 physicians were occupied iu the study of his works, and in vain 

 attempts to reconcile the phenomena of nature with the dicta of their 

 master, they had little time aud less inclination to interrogate Nature 

 herself, aud pursue the study of medicine iu those field* in which alone 

 it can be followed with success. 



Galen was a most voluminous writer. Though many of his works 

 are said to have been burnt in his house at Rome, and others in the 

 course of time have been lost, there are still extant 137 treatises and 

 fragments of treatises, of which 82 are considered undoubtedly genuine. 



