of observer； experimenter and philosopher。 His father； Nikon； a prosperous architect； was urged in a dream to devote his son to the profession of medicine； upon which study the lad entered in his seventeenth year under Satyrus。 In his writings； Galen gives many details of his life； mentioning the names of his teachers； and many incidents in his Wanderjahre； during which he studied at the best medical schools； including Alexandria。 Returning to his native city he was put in charge of the gladiators； whose wounds he said he treated with wine。 In the year 162； he paid his first visit to Rome； the scene of his greatest labors。 Here he gave public lectures on anatomy； and became 〃the fashion。〃 He mentions many of his successes； one of them is the well…worn story told also of Erasistratus and Stratonice； but Galen's story is worth telling； and it is figured as a miniature in the manuscripts of his works。 Called to see a lady he found her suffering from general malaise without any fever or increased action of the pulse。 He saw at once that her trouble was mental and； like a wise physician； engaged her in general conversation。 Quite possibly he knew her story； for the name of a certain actor； Pylades； was mentioned； and he noticed that her pulse at once increased in rapidity and became irregular。 On the next day he arranged that the name of another actor； Morphus； should be mentioned； and on the third day the experiment was repeated but without effect。 Then on the fourth evening it was again mentioned that Pylades was dancing； and the pulse quickened and became irregular； so he concluded that she was in love with Pylades。 He tells how he was first called to treat the Emperor Marcus Aurelius； who had a stomach…ache after eating too much cheese。 He treated the case so successfully that the Emperor remarked； 〃I have but one physician； and he is a gentleman。〃 He seems to have had good fees； as he received 400 aurei （about 2000） for a fortnight's attendance upon the wife of Boethus。
He left Rome for a time in 168 A。 D。 and returned to Pergamon； but was recalled to Rome by the Emperor； whom he accompanied on an expedition to Germany。 There are records in his writings of many journeys； and busy with his practice in dissections and experiments he passed a long and energetic life； dying； according to most authorities； in the year 200 A。D。
A sketch of the state of medicine in Rome is given by Celsus in the first of his eight books； and he mentions the names of many of the leading practitioners； particularly Asclepiades； the Bithynian； a man of great ability； and a follower of the Alexandrians； who regarded all disease as due to a disturbed movement of the atoms。 Diet； exercise； massage and bathing were his great remedies； and his mottotuto； cito et jucundehas been the emulation of all physicians。 How important a role he and his successors played until the time of Galen may be gathered from the learned lectures of Sir Clifford Allbutt＇32＇ on 〃Greek Medicine in Rome〃 and from Meyer…Steineg's 〃Theodorus Priscianus und die romische Medizin。〃＇33＇ From certain lay writers we learn that it was the custom for popular physicians to be followed on their rounds by crowds of students。 Martial's epigram （V； ix） is often referred to：
Languebam： sed tu comitatus protinus ad me Venisti centum； Symmache； discipulis。 Centum me tegigere manus Aquilone gelatae Non habui febrem； Symmache； nunc habeo。
＇32＇ Allbutt： British Medical Journal； London； 1909； ii； 1449； 1515； 1598。
＇33＇ Fischer； Jena； 1909。
And in the 〃Apollonius of Tyana〃 by Philostratus； when Apollonius wishes to prove an alibi； he calls to witness the physicians of his sick friend； Seleucus and Straloctes； who were accompanied by their clinical class to the number of about thirty students。＇34＇ But for a first…hand sketch of the condition of the profession we must go to Pliny； whose account in the twenty…ninth book of the 〃Natural History〃 is one of the most interesting and amusing chapters in that delightful work。 He quotes Cato's tirade against Greek physicians；corrupters of the race； whom he would have banished from the city；then he sketches the career of some of the more famous of the physicians under the Empire； some of whom must have had incomes never approached at any other period in the history of medicine。 The chapter gives a good picture of the stage on which Galen （practically a contemporary of Pliny） was to play so important a role。 Pliny seems himself to have been rather disgusted with the devious paths of the doctors of his day； and there is no one who has touched with stronger language upon the weak points of the art of physic。 In one place he says that it alone has this peculiar art and privilege； 〃That whosoever professeth himself a physician； is straightwaies beleeved； say what he will： and yet to speake a truth； there are no lies dearer sold or more daungerous than those which proceed out of a Physician's mouth。 Howbeit； we never once regard or look to that； so blind we are in our deepe persuasion of them； and feed our selves each one in a sweet hope and plausible conceit of our health by them。 Moreover； this mischief there is besides； That there is no law or statute to punish the ignorance of blind Physicians； though a man lost his life by them： neither was there ever any man knowne； who had revenge of recompence for the evill intreating or misusage under their hands。 They learne their skill by endaungering our lives： and to make proofe and experiments of their medicines； they care not to kill us。〃＇35＇ He says it is hard that； while the judges are carefully chosen and selected； physicians are practically their own judges； and that of the men who may give us a quick despatch and send us to Heaven or Hell； no enquiry or examination is made of their quality and worthiness。 It is interesting to read so early a bitter criticism of the famous 〃Theriaca；〃 a great compound medicine invented by Antiochus III； which had a vogue for fifteen hundred years。
＇34＇ Bk。 VIII； Chap。 VII。
＇35＇ Pliny： Natural History （XXIX； 1）； Philemon Holland's version； London； 1601； II； 347。
But we must return to Galen and his works； which comprise the most voluminous body of writings left by any of the ancients。 The great edition is that in twenty…two volumes by Kuhn （1821…1833）。 The most useful editions are the 〃Juntines〃 of Venice； which were issued in thirteen editions。 In the fourth and subsequent editions a very useful index by Brassavola is included。 A critical study of the writings is at present being made by German scholars for the Prussian Academy； which will issue a definitive edition of his works。
Galen had an eclectic mind and could not identify himself with any of the prevailing schools； but regarded himself as a disciple of Hippocrates。 For our purpose； both his philosophy and his practice are of minor interest in comparison with his great labors in anatomy and physiology。
In anatomy； he was a pupil of the Alexandrians to whom he constantly refers。 Times must have changed since the days of Herophilus； as Galen does not seem ever to have had an opportunity of dissecting the human body； and he laments the prejudice which prevents it。 In the study of osteology； he urges the student to be on the lookout for an occasional human bone exposed in a graveyard； and on one occasion he tells of finding the carcass of a robber with the bones picked bare by birds and beasts。 Failing this source； he advises the student to go to Alexandria； where there were still two skeletons。 He himself dissected chiefly apes and pigs。 His osteology was admirable； and his little tractate 〃De Ossibus〃 could； with very few changes； be used today by a hygiene class as a manual。 His description of the muscles and of the organs is very full； covering； of course； many sins of omission and of commission； but it was the culmination of the study of the subject by Greek physicians。
His work as a physiologist was even more important； for； so far as we know； he was the first to carry out experiments on a large scale。 In the first place； he was within an ace of discovering the circulation of the blood。 You may remember that through the errors of Praxagoras and Erasistratus； the arteries were believed to contain air and got their name on that account： Galen showed by experiment that the arteries contain blood and not air。 He studied particularly the movements of the heart； the action of the valves； and the pulsatile forces in the arteries。 Of the two kinds of blood； the one； contained in the venous system； was dark and thick and rich in grosser elements； and served for the general nutrition of the body。 This system took its origin； as is clearly shown in the figure； in the liver； the central organ of nutrition and of sanguification。 From the portal system were absorbed； through the stomach and intestines； the products of digestion。 From the liver extend the venae cavae； one to supply the head and arms； the other the lower extremities： extending from the right heart was a branch； corresponding to the pulmonary artery； the arterial vein which distributed blood to the lungs。 This was the closed venous system。 The arterial system； shown； as you see； quite separate in Figure 31； was full of a thinner； brighter； warmer blood； characterized by the presence of an abundance of the vital spirits。 Warmed in the ventricle； it distributed vital heat to all parts of the body。 The two systems were closed and communicated with each other only through certain pores or perforations in the septum separating the ventricles。 At the periphery； however； Galen recognized （as had been done already by the Alexandrians） that the arteries anastomose with the veins； 〃。 。 。 and they mutually receive from each other blood and spirits through certain invisible and extremely small vessels。〃
It is difficult to understand how Galen missed the circulation of the blood。 He knew that the valves of the heart determined the direction of the blood that entered and left the organ； but he did not appreciate that it was a pump for distributing the blood； regarding it rather as a fireplace from which the innate heat of the body was derived。 He knew that the pulsatile force was resident in the walls of the heart and in the arteries； a