January 6, 192 1] 



NATURE 



613 



the discovery of much of the classical literature which 

 had been hidden away in the libraries of the East. 

 The first effect of the revival was to strengthen the 

 position of Galen. With the revival of Greek in the 

 fifteenth century his original writings became ac- 

 cessible, and manuscripts hitherto unknown came to 

 light, it became the aim of the scholars of the time 

 to translate these works into polished Latin for the 

 benefit of those unacquainted with Greek. -Amongst 

 the medical humanists, as they are termed, was the 

 founder and first president of this college. There is 

 no more honoured name in scholarship than that of 

 Linacre, but it is instructive to note the difference 

 between his mental attitude and that of Harvey, little 

 more than a hundred years later. Linacre stands for 

 the revival of learning. Harvey for the intellectual 

 quickening that revival was to engender. The avowed 

 aim of the medical humanists was not the advance of 

 medical science, but a return to the uncorrupted 

 knowledge of the Greeks ; the thought and science of 

 antiquity were still held so immeasurably superior 

 to anything that modern times could produce that no 

 advance was contemplated. But the seed was sown. 

 Greek literature was the product of an original 

 creative activity and a mental freedom to which 

 Europe had been long unaccustomed. Men could not 

 studv it without at the same time drinking in some- 

 thing,' of the spirit in which it had been conceived and 

 which animates it for all time. This was our true 

 heritage in the Renaissance, and once again imbued 

 with this spirit men felt at liberty to ask whether 

 the ancients were always right and to criticise and 

 test their statements. The reign of mere authority 

 came to an end, and science recommenced that 

 advance which has continued to the present day. 



The first science to bear new fruit was anatomy. 

 It was in Italv that the resurrection began, and the 

 book written fcy Vesalius on "The Structure of the 

 Human Body," published in 1543, set the seal upon 

 the new method — the appeal to fact instead of to 

 dogma. We all know that the truth as to the pul- 

 monarv circulation was first ascertained, while it was 

 reserved for Harvey to demonstrate the systemic cir- 

 cuit. The method of experiment as an adjunct to 

 observation, instead of being delayed for hundreds of 

 years, as it had been amongst the Greeks, was now, 

 thanks to Galen, an instrument ready to hand. .And 

 ''":s it came about that when a man arose dreplv 

 lied with the true spirit of science and capable of 

 .. iiij this instrument with intelligence and an open 

 mind, his study of the circulation was at once re- 

 warded by a discovery of capital importance. 



William Harvey stands as one of the landmarks 

 ;in the history of medical science. His was the first 

 scientific discovery of absolutely first-rate importance 

 [to be made bv the application of the methods and 

 ' 'it now revived from ancient times ; he possessed 

 vision, the power of imagination, as well as the 

 Iful industry and patience in gathering; his facts 

 in devising his experiments. 

 Harvev has left us two treatises of unequal great- 

 ness. The " De Mofu Cordis " has no need of anv 

 fntrodurtorv disquisition on srientifir method, for it 

 itself is the method incarnate. If is the mature work 

 of a master who is sure of his ground ; it sweeps us 

 along from one short chapter to another, each filled 

 with accurate observation and close reasoning, so that 

 • loubt.or hesitation is possible to the reader. 

 !iit he also essaved to solve other biological 

 '<lems, for which his means were not adequate, 

 ! the "De Generatione." which he was reluctant to 

 lish,_ is readinij of n different kind. The most 

 rurtive part of this fre.itise Is perhaps the intro- 

 'ion on scientific method. "Of the Manner and 

 !'T of .Arguirine Knowledge." Here Harvev in 

 NO. 2671, VOL. T06] 



his later age sets forth the principles which had guided 

 him, with -Aristotle as his leader, in his life's work, 

 and we realise how truly scientific were his methods. 



With Harvey, we feel that medical science has fairly 

 entered the right path. The conditions essential to 

 scientific progress — freedom of thought, accuracy of 

 observation, imagination, experimental verification, 

 and logical reasoning — all are exemplified in Harvey's 

 work. 



There is room for difference of opinion as to the 

 impulses from external sources which have had the 

 most far-reaching effects upon medicine since Harvey's 

 day, but I would name four as of exceptional im- 

 portance. They are the invention of the compound 

 microscope, the development of chemistry, the accept- 

 ance of the doctrine of evolution, and the discovery of 

 the relation of micro-organisms to disease. The 

 microscope was invented in Holland late in the 

 sixteenth century, but its possibilities as an aid to 

 anatomy were not at first grasped, and it w-as not 

 until after Harvey's death that Malpighi actually saw 

 the capillaries and the contrary direction of the blood- 

 flow in arteries and veins. The rise of histology from 

 that time forward has transformed our ideas of the 

 structure of the body, and with each improvement 

 in the microscope our horizon has widened. We have 

 passed from the organ to the units of which it is 

 built up, and Virchow's "Cellular Pathology" marks 

 an epoch in medicine. To-day we are a stage further, 

 for the inquiry is being pushed into the more intimate 

 structure of the cell itself, in the hope of revealing 

 the nature of the pirocesses by which it carries on its 

 work. 



The rise of physics and chemistrv has been even 

 more fruitful for medicine. We cannot nowadays con- 

 sider them separately, so closely merged have they 

 become. We recognise the fundamental importance 

 of these sciences for the right understanding of phvsio- 

 logv and pathology by placing them at the root of 

 medical education. 



Chemistry has influenced medicine from the days 

 of alchemy onwards; Paracelsus and Van Helmo'nt 

 stand out as picturesque figures in its history. In 

 England the rise of physics and chemistry began in 

 Harvey's lifetime with those meetings of scientific 

 men which later gave birth to the Royal Society. It 

 must not be forgotten that the work of such men as 

 Boyle, Hooke, Lower, and Mayow practlcnllv solved 

 the problem of respiration not long after Harvey's 

 death — a problem second only in Importance to that 

 of the circulation — though a century was to elapse 

 for its full meaning to become clear vi-ith the discovery 

 of oxygen. Every advance in physics and chemistry 

 has borne fruit ifor us in its turn ; to-day we can 

 almost affirm that the chief issues in phvsiologv and 

 pathology are to be sought In the chemical activities 

 of the human body. These, .again, are bound up with 

 physical conditions, and there is one recent branch of 

 chemistry the possibilities of which are only beginning 

 to be appreciated in medicine. If we reflect that the 

 bodv, from a chemical point of view, consists almost 

 entirelv of colloids, the behaviour of which is still 

 imperfectly understood, it will be realised that ad- 

 vances in colloidal chemistry are destined to throw a 

 flood of light upon the processes of vital activitv. 



The^ doctrine of evolution has scarcely received the 

 attention it merits as .i f.irtor in moidlfving the 

 opinions of me<lical science. So long as it was be- 

 lieved that the body, with all its natural functions, 

 had been created from the first in its present condition, 

 there was little room for inquirv Into the origin of 

 those functions, and still less into th.Tt of morbid 

 processes. D.irwin has changed all this. a« a single 

 instance will suffice to show. Metchnikoff's studies 

 on the comparative pathology of inflammation have 



