Part 6 (1/2)

These things, therefore, happen together or at the same instant: the tension of the heart, the pulse of its apex, which is felt externally by its striking against the chest, the thickening of its parietes, and the forcible expulsion of the blood it contains by the constriction of its ventricles

Hence the very opposite of the opinions coenerally believed that when the heart strikes the breast and the pulse is felt without, the heart is dilated in its ventricles and is filled with blood; but the contrary of this is the fact, and the heart, when it contracts (and the ih the chest wall), is earded as the diastole of the heart, is in truth its systole And in like manner the intrinsic motion of the heart is not the diastole but the systole; neither is it in the diastole that the heart grows firm and tense, but in the systole, for then only, when tense, is it orous

Neither is it by any means to be allowed that the heart only reat Vesalius giving this notion countenance, quotes a bundle of osiers bound in a pyra, that as the apex is approached to the base, so are the sides e out in the fashi+on of arches, the cavities to dilate, the ventricles to acquire the forlass and so to suck in the blood But the true effect of every one of its fibres is to constringe the heart at the same time they render it tense; and this rather with the effect of thickening and a its ventricles

And, again, as the fibres run from the apex to the base, and draw the apex towards the base, they do not tend to e out in circles, but rather the contrary; inasmuch as every fibre that is circularly disposed, tends to becoht when it contracts; and is distended laterally and thickened, as in the case of eneral, when they contract, that is, when they are shortened longitudinally, as we see thee To all this let it be added, that not only are the ventricles contracted in virtue of the direction and condensation of their walls, but farther, that those fibres, or bands, styled nerves by Aristotle, which are so conspicuous in the ventricles of the larger aniht fibres (the parietes of the heart containing only circular ones), when they contract simultaneously by an adether as if with cords, and so is the charge of blood expelled with force

Neither is it true, as vulgarly believed, that the heart by any dilatation orthe blood into the ventricles; for when it acts and becomes tense, the blood is expelled; when it relaxes and sinks together it receives the blood in the manner and hich will by-and-by be explained

CHAPTER III

OF THE MOTIONS OF THE ARTERIES, AS SEEN IN THE DISSECTION OF LIVING ANIMALS

In connexion with the s are further to be observed having reference to the motions and pulses of the arteries

1 At the moment the heart contracts, and when the breast is struck, when in short the organ is in its state of systole, the arteries are dilated, yield a pulse, and are in the state of diastole In like ht ventricle contracts and propels its charge of blood, the pulmonary artery is distended at the same time with the other arteries of the body

2 When the left ventricle ceases to act, to contract, to pulsate, the pulse in the arteries also ceases; further, when this ventricle contracts languidly, the pulse in the arteries is scarcely perceptible In like , the pulse in the pulmonary artery ceases also

3 Further, when an artery is divided or punctured, the blood is seen to be forcibly propelled froain, when the pul forth with violence at the instant when the right ventricle contracts

So also in fishes, if the vessel which leads froills be divided, at the moment when the heart becomes tense and contracted, at the same moment does the blood floith force from the divided vessel

In the same e see the blood in arteriotoreater, now to a less distance, and that the greater jet corresponds to the diastole of the artery and to the time when the heart contracts and strikes the ribs, and is in its state of systole, we understand that the blood is expelled by the same movement

From these facts it is manifest, in opposition to commonly received opinions, that the diastole of the arteries corresponds with the time of the heart's systole; and that the arteries are filled and distended by the blood forced into them by the contraction of the ventricles; the arteries, therefore, are distended, because they are filled like sacs or bladders, and are not filled because they expand like bellows It is in virtue of one and the same cause, therefore, that all the arteries of the body pulsate, viz, the contraction of the left ventricle; in the same way as the pulht ventricle

Finally, that the pulses of the arteries are due to the impulses of the blood fro into a glove, when the whole of the fingers will be found to become distended at one and the same time, and in their tension to bear some resemblance to the pulse For in the ratio of the tension is the pulse of the heart, fuller, stronger, andthe rhythm and volume, and order of the heart's contractions Nor is it to be expected that because of the motion of the blood, the time at which the contraction of the heart takes place, and that at which the pulse in an artery (especially a distant one) is felt, shall be otherwise than silove or bladder; for in a plenu piece of timber, etc) the stroke and the motion occur at both extremities at the same time Aristotle, [Footnote: De Anim, iii, cap 9] too, has said, ”the blood of all ani the arteries), and by the pulse is sent everywhere simultaneously” And further, [Footnote: De Respir, cap 20] ”thus do all the veins pulsate together and by successive strokes, because they all depend upon the heart; and, as it is always in ether, but by successive movements” It is well to observe with Galen, in this place, that the old philosophers called the arteries veins I happened upon one occasion to have a particular case under my care, which plainly satisfied e pulsating tuht side of the neck, called an aneurism, just at that part where the artery descends into the axilla, produced by an erosion of the artery itself, and daily increasing in size; this tue of blood brought to it by the artery, with each stroke of the heart; the connexion of parts was obvious when the body of the patient came to be opened after his death The pulse in the corresponding arreater portion of the blood being diverted into the tumour and so intercepted

Whence it appears that whenever the h the arteries is impeded, whether it be by compression or infarction, or interception, there do the re that the pulse of the arteries is nothing more than the impulse or shock of the blood in these vessels

CHAPTER IV

OF THE MOTION OF THE HEART AND ITS AURICLES, AS SEEN IN THE BODIES OF LIVING ANIMALS

Besides the motions already spoken of, we have still to consider those that appertain to the auricles

Caspar Bauhin and John Riolan, [Footnote: i Bauhin, lib ii cap

II Riolan lib viii, cap I] most learned men and skilful anatomists, inform us that from their observations, that if we carefully watch the movements of the heart in the vivisection of an animal, we shall perceive four motions distinct in time and in place, two of which are proper to the auricles, two to the ventricles With all deference to such authority I say that there are four motions distinct in point of place, but not of tiether, and so also do the two ventricles, in such wise that though the places be four, the ti ether: one of the auricles, another of the ventricles; these by noplace si, that of the heart following; the in fros are beco, as also in fishes and the colder blooded animals there is a short pause between these two motions, so that the heart aroused, as it were, appears to respond to the th, when near to death, it ceases to respond by its proper htly ns ofauricles than actually to move The heart, therefore, ceases to pulsate sooner than the auricles, so that the auricles have been said to outlive it, the left ventricle ceasing to pulsate first of all; then its auricle, next the right ventricle; and, finally, all the other parts being at rest and dead, as Galen long since observed, the right auricle still continues to beat; life, therefore, appears to linger longest in the right auricle Whilst the heart is gradually dying, it is sometimes seen to reply, after two or three contractions of the auricles, roused as it were to action, and ly, and with an effort

But this especially is to be noted, that after the heart has ceased to beat, the auricles however still contracting, a finger placed upon the ventricles perceives the several pulsations of the auricles, precisely in the same way and for the same reason, as we have said, that the pulses of the ventricles are felt in the arteries, to wit, the distension produced by the jet of blood And if at this ti, the point of the heart be cut off with a pair of scissors, you will perceive the blood flowing out upon each contraction of the auricles Whence it is manifest that the blood enters the ventricles, not by any attraction or dilatation of the heart, but by being thrown into them by the pulses of the auricles