The first of the thick Guts, known by the Name of _Coecum_, is very short, and properly only an _Appendix_ or Bag of a Finger's length. That which follows is the _Colon_, being the largest of all, and full of little Cells, which are fill'd sometimes with Wind and other Matters that excite the Pains of the Colick. It encompasseth the thin Guts, in passing from the top to the bottom of the Belly, by the means of its great Circumvolutions, and is from eight to nine Foot long. The last is the _Rectum_ or {71} streight Gut, so nam'd, because it goes directly to the Fundament: It is no longer than ones Hand, but it is fleshy, and situated upon the _Os Sacrum_, and the _Coccyx_ or Rump-Bone. _What is the _Peristaltick_ Motion of the Guts?_ It is the successive Motion and Undulation, whereby the Guts insensibly push forward from the top to the bottom, the Matters contain'd in them; and that Motion which on the contrary is perform'd from the bottom to the top, is term'd the _Antiperistaltick_ as it happens in the _Iliack_ Passion, or twisting of the Guts, call'd _Domine Miserere_, by reason of its intolerable Pain. _What is the Mesentery?_ It is a kind of Membrane somewhat fleshy, which is join'd to the Spine in the bottom and middle of the Belly, and by its folding, keeps all the Guts steady in their place; it is all over beset with red, white, and Lymphatick Vessels; that is to say, those that carry the Blood, Chyle, and _Lympha_, which serves to cause this last to run more freely, and to ferment. Three notable Glandules are also observ'd therein, the greatest whereof lies in the middle, and is nam'd _Asellius's Pancreas_; the two other lesser are call'd _Lumbar_ Glandules, as being situated near the Left Kidney. From each of these Glandules proceeds a small Branch; and both are united together to make the great _Lacteal_ Vein, or _Thoracick_ Canal. This Tube conveys the Chyle along the _Vertebra's_ of the Back to the Left _Subclavian_ Vein; from whence it passeth into the ascending _Vena Cava_, and descends in the Right Ventricle of the Heart, {72} where it assumes the form of Blood; from whence it passeth to the Lungs thro' the _Pulmonary_ Artery; then it returns to the Heart thro' the _Pulmonary_ Vein, and goes forth again thro' the Left Ventricle of the Heart, between the _Aorta_ or great Artery, to be afterward distributed to all the Parts of the Body. This is the ordinary Passage for the Circulation of the Chyle, and the Sanguification of the Heart. _What is the Liver?_