HEART AND BLOOD. 81 



draw aught into its cavity during the diastole, unless, like a 

 sponge, it has been first compressed, and as it is returning to 

 its primary condition ; but in animals all local motion proceeds 

 from, and has its original in the contraction of some part : it is 

 consequently by the contraction of the auricles that the blood 

 is thrown into the ventricles, as I have already shown, and from 

 thence, by the contraction of the ventricles, it is propelled and 

 distributed. Which truth concerning local motions, and how 

 the immediate moving organ in every motion of an animal 

 primarily endowed with a motive spirit (as Aristotle has it, 1 ) is 

 contractile ; and in what way the word vtvpov is derived from 

 i>eww, nuto, contraho; and how Aristotle was acquainted with 

 the muscles, and did not unadvisedly refer all motion in animals 

 to the nerves, or to the contractile element, and therefore called 

 those little bands in the heart nerves all this, if I am per- 

 mitted to proceed in my purpose of making a particular de- 

 monstration of the organs of motion in animals from observa- 

 tions in my possession, I trust I shall be able to make sufficiently 

 plain. 



But that we may go on with the subject we have in hand, 

 viz., the use of the auricles in filling the ventricles : we should 

 expect that the more dense and compact the heart, the thicker 

 its parietes, the stronger and more muscular must be the auricle 

 to force and fill it, and vice versa. Now this is actually so : 

 in some the auricle presents itself as a sanguinolent vesicle, as 

 a thin membrane containing blood, as in fishes, in which the 

 sac that stands in lieu of the auricle, is of such delicacy and 

 ample capacity, that it seems to be suspended or to float 

 above the heart ; in those fishes in which the sac is somewhat 

 more fleshy, as in the carp, barbel, tench, and others, it bears 

 a wonderful and strong resemblance to the lungs. 



In some men of sturdier frame and stouter make, the right 

 auricle is so strong> and so curiously constructed within of 

 bands and variously interlacing fibres, that it seems to equal 

 the ventricle of the heart in other subjects; and I must 

 say that I am astonished to find such diversity in this par- 

 ticular in different individuals. It is to be observed, however, 

 that in the foetus the auricles are out of all proportion large, 



1 In the book, de Spiritu, and elsewhere. 



