the evolution of modern medicine(现代医药的演变)-第33章
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Vesalius this is a trifling booklet； but if not its equal in bulk or
typographical beauty （it is in fact very poorly printed）； it is its counterpart
in physiology； and did for that science what Vesalius had done for anatomy；
though not in the same way。 The experimental spirit was abroad in the
land； and as a student at Padua； Harvey must have had many opportunities
of learning the technique of vivisection； but no one before his day had
attempted an elaborate piece of experimental work deliberately planned to
solve a problem relating to the most important single function of the body。
Herein lies the special merit of his work； from every page of which there
breathes the modern spirit。 To him； as to Vesalius before him； the current
views of the movements of the blood were unsatisfactory； more
particularly the movements of the heart and arteries； which were regarded
as an active expansion by which they were filled with blood； like bellows
with air。 The question of the transmission of blood through the thick
septum and the transference of air and blood from the lungs to the heart
were secrets which he was desirous of searching out by means of
experiment。
＇27＇ Harvey： Exercitatio Anatomica de Motu Cordis et Sanguinis in
Animalibus； Francofurti； 1628。
One or two special points in the work may be referred to as
illustrating his method。 He undertook first the movements of the heart； a
task so truly arduous and so full of difficulties that he was almost tempted
to think with Fracastorius that 〃the movement of the heart was only to be
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comprehended by God。〃 But after many difficulties he made the following
statements： first； that the heart is erected and raises itself up into an apex；
and at this time strikes against the breast and the pulse is felt externally；
secondly； that it is contracted every…way； but more so at the sides； and
thirdly； that grasped in the hand it was felt to become harder at the time of
its motion； from all of which actions Harvey drew the very natural
conclusion that the activity of the heart consisted in a contraction of its
fibres by which it expelled the blood from the ventricles。 These were the
first four fundamental facts which really opened the way for the discovery
of the circulation； as it did away with the belief that the heart in its motion
attracts blood into the ventricles； stating on the contrary that by its
contraction it expelled the blood and only received it during its period of
repose or relaxation。 Then he proceeded to study the action of the arteries
and showed that their period of diastole； or expansion； corresponded with
the systole； or contraction； of the heart； and that the arterial pulse follows
the force； frequency and rhythm of the ventricle and is； in fact； dependent
upon it。 Here was another new fact： that the pulsation in the arteries was
nothing else than the impulse of the blood within them。 Chapter IV； in
which he describes the movements of the auricles and ventricles； is a
model of accurate description； to which little has since been added。 It is
interesting to note that he mentions what is probably auricular fibrillation。
He says： 〃After the heart had ceased pulsating an undulation or palpitation
remained in the blood itself which was contained in the right auricle； this
being observed so long as it was imbued with heat and spirit。〃 He
recognized too the importance of the auricles as the first to move and the
last to die。 The accuracy and vividness of Harvey's description of the
motion of the heart have been appreciated by generations of physiologists。
Having grasped this first essential fact； that the heart was an organ for the
propulsion of blood； he takes up in Chapters VI and VII the question of the
conveyance of the blood from the right side of the heart to the left。 Galen
had already insisted that some blood passed from the right ventricle to the
lungsenough for their nutrition； but Harvey points out； with Colombo；
that from the arrangement of the valves there could be no other view than
that with each impulse of the heart blood passes from the right ventricle to
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the lungs and so to the left side of the heart。 How it passed through the
lungs was a problem： probably by a continuous transudation。 In Chapters
VIII and IX he deals with the amount of blood passing through the heart
from the veins to the arteries。 Let me quote here what he says； as it is of
cardinal import：
〃But what remains to be said upon the quantity and source of the blood
which thus passes； is of a character so novel and unheard of that I not only
fear injury to myself from the envy of a few； but I tremble lest I have
mankind at large for my enemies； so much doth wont and custom become
a second nature。 Doctrine once sown strikes deeply its root； and respect for
antiquity influences all men。 Still the die is cast； and my trust is in my love
of truth； and the candour of cultivated minds。〃＇28＇ Then he goes on to say：
＇28＇ William Harvey： Exercitatio Anatomica de Motu Cordis et
Sanguinis in Animalibus； Francofurti； 1628； G。 Moreton's facsimile reprint
and translation； Canterbury； 1894； p。 48。
I began to think whether there might not be A MOVEMENT； AS IT
WERE； IN A CIRCLE。 Now this I afterwards found to be true； and I
finally saw that the blood； forced by the action of the left ventricle into the
arteries； was distributed to the body at large； and its several parts； in the
same manner as it is sent through the lungs； impelled by the right ventricle
into the pulmonary artery； and that it then passed through the veins and
along the vena cava； and so round to the left ventricle in the manner
already indicated。〃＇29＇
＇29＇ Ibid。 p。 49。
The experiments dealing with the transmission of blood in the veins
are very accurate； and he uses the old experiment that Fabricius had
employed to show the valves； to demonstrate that the blood in the veins
flows towards the heart。 For the first time a proper explanation of the
action of the valves is given。 Harvey had no appreciation of how the
arteries and veins communicated with each other。 Galen； you may
remember； recognized that there were anastomoses； but Harvey preferred
the idea of filtration。
The 〃De Motu Cordis〃 constitutes a unique piece of work in the
history of medicine。 Nothing of the same type had appeared before。 It is a
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thoroughly sensible； scientific study of a definite problem； the solution of
which was arrived at through the combination of accurate observation and
ingenious experiment。 Much misunderstanding has arisen in connection
with Harvey's discovery of the circulation of the blood。 He did not
discover that the blood moved；that was known to Aristotle and to Galen；
from both of whom I have given quotations which indicate clearly that
they knew of its movement；but at the time of Harvey not a single
anatomist had escaped from the domination of Galen's views。 Both
Servetus and Colombo knew of the pulmonary circulation； which was
described by the former in very accurate terms。 Cesalpinus； a great name
in anatomy and botany； for whom is claimed the discovery of the
circulation； only expressed the accepted doctrines in the following oft…
quoted phrase：
〃We will now consider how the attraction of aliment and the process of
nutrition takes place in plants； for in animals we see the aliment brought
through the veins to the heart； as to a laboratory of innate heat； and； after
receiving there its final perfection； distributed through the arteries to the
body at large； by the agency of the spirits produced from this same aliment
in the heart。〃＇30＇ There is nothing in this but Galen's view； and Cesalpinus
believed； as did all his contemporaries； that the blood was distributed
through the body by the vena cava and its branches for the nourishment of
all its parts。＇*＇ To those who have any doubts as to Harvey's position in
this matter I would recommend the reading of the 〃De Motu Cordis〃 itself；
then the various passages relating to the circulation from Aristotle to
Vesalius。 Many of these can be found in the admirable works of Dalton；
Flourens； Richet and Curtis。＇31＇ In my Harveian Oration for 1906＇32＇ I
have dealt specially with the reception of the new views； and have shown
how long it was before the reverence for Galen allowed of their
acceptance。 The University of Paris opposed the circulation of the blood
for more than half a century after the appearance of the 〃De Motu Cordis。〃
＇30＇ De Plantis； Lib I； cap。 2。
＇*＇ Cesalpinus has also a definite statement of the circlewise process。
Ed。
＇31＇ J。 C。 Dalton Doctrines of the Circulation； Philadelphia； 1884；
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Flourens Histoire de la decouverte de la circulation du sang； 2d ed。； Paris；
1857； Charles Richet Harvey； la circulation du sang； Paris； 1879； John G。
Curtis Harvey's views on the use of Circulation； etc。； New York； 1916。
＇32＇ Osler An Alabama Student and Other Biographical Essays；
Oxford； 1908； p。 295。
To summarizeuntil the seventeenth century there were believed to
be two closed systems in the circulation； （1） the natural； containing venous
blood； had its origin in the liver from which； as from a fountain； the blood
continually ebbed and flowed for the nourishment of the body； （2） the vital；
containin
