Q. How is it that the heart is continually moving? A. Because in it there is a certain spirit which is more subtle than air, and by reason of its thickness and rarefaction, seeks a larger space, filling the hollow room of the heart; hence the dilating and opening of the heart, and because the heart is earthly the thrusting and moving ceasing, its parts are at rest, tending downwards. As a proof of this, take an acorn, which, if put into the fire, the heat doth dissolve its humidity, therefore occupies a greater space, so that the rind cannot contain it, but puffs up, and throws it into the fire. The like of the heart. Therefore the heart of a living creature is triangular, having its least part towards its left side, and the greater towards the right; and doth also open and shut in the least part, by which means it is in continual motion; the first motion is called _diastole_, that is extending the heart or breast; the other _systole_, that is, shutting of the heart; and from these all the motions of the body proceed, and that of the pulse which the physicians feel. Q. How comes it that the flesh of the heart is so compact and knit together? A. Because in thick compacted substances heat is commonly received and united. And because the heart with its heat should moderate the coldness of the brain, it is made of that fat flesh apt to keep a strong heat. Q. How comes the heart to be the hottest part of all living creatures? A. It is so compacted as to receive the heat best, and because it should mitigate the coldness of the brain. Q. Why is the heart the beginning of life? A. It is plain that in it the vital spirit is bred, which is the heat of life; and therefore the heart having two receptacles, viz., the right and the left the right hath more blood than spirits; which spirit is engendered to give life and vivify the body. Q. Why is the heart long and sharp like a pyramid? A. The round figure hath an angle, therefore the heart is round, for fear any poison or hurtful matter should be retained in it; and because that figure is fittest for motion. Q. How comes the blood chiefly to be in the heart? A. The blood in the heart has its proper or efficient place, which some attribute to the liver; and therefore the heart doth not receive blood from any other parts but all other parts of it. Q. How happens it that some creatures want a heart? A. Although they have no heart, yet they have somewhat that answers for it, as appears in eels and fish that have the back bone instead of the heart. Q. Why does the heart beat in some creatures after the head is cut off, as in birds and hens? A. Because the heart lives first and dies last, and therefore beats longer than other parts.