"There (say they) is the mansion and Tribunal of the soul where heat is to be found, the first instrument of all the functions; but the Heart is the springing fountain of Native heat, which by the arteries as it were by small riverers, is derived into the whole body."
— Crooke, Helkiah (1576-1648)
Ti's naught to haue moe Kings then one,
Let him that raygnes, raygne King alone.
So in the Microcosme or Little world, there must be but one principle, one prince, which is the Heart, whose excellencie and dignity aboue the rest of the partes, these things doe cleerely demonstrate. First, because it first liueth, and dyeth the last; and therefore is the originall of life, and the seat of the soule. Next, because it endureth no notable disease, but yeildeth presently to Nature if it be afflicted. Againe, because it obtaineth the most honourable place, that is, the middle of the body. Fourthly, for that by his perpetuall motion, all thinges are exhilerated and doe flourish: and nothing in the whole Creature is fruitfull, vnlesse the powerfull vigour of the Heart do giue foecundity vnto it. There (say they) is the mansion and Tribunall of the soule where heate is to be found, the first instrument of all the functions; but the Heart is the springing fountaine of Natiue heate, which by the arteries as it were by small riuerers, is deriued into the whole bodie. Moreouer, the seate of the faculties is there, where the Organs of the same faculties doe appeare; but all the veines, arteries, & sinewes, doe arise out of the Heart. For the arteries no man euer made doubt. The veines doe surely arise thence, where their end and termination doeth appeare: but that is about the Heart; for the implantation of the great arterie and the hollow veine are alike. Beside, all the veines are continuated with the heart, to it are they fixed, where they also haue membranes set like dores vnto them, which seeme to bee the beginnings and heads of the veines; but through the Liuer they are onely disseminated, and the rest of the entralles they make a passage through, and so end into haire strings. Aristotle also is of opinion, that the hart is the originall of the nerues; for his flesh is hard, thight,and somewhat membranous; but the ventricles thereof haue in them infinite textures of manifest sinewes.
(I.Qii, pp. 39-40)