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,
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?
The Liver, being the thickest of all the Bowels, is plac'd in the Right Hypochondrium, at the distance only of a Fingers breadth from the Diaphragm; its Figure much resembling that of a thick piece of Beef: It is Convex on the outside, and Concave within; its Substance is soft and tender, its Colour and Consistence being like coagulated Blood: It is cleft at bottom, and divided into two Lobes, viz. one greater, and the other less: Its Office is to purifie the Mass of Blood by Filtration; and it is bound by two strong Ligaments, the first whereof adheres to the Diaphragm, and the second to the Xiphoides or Sword-like Cartilage. Two great Veins take their Rise from hence, viz. the Vena Portæ, and the Vena Cava, which form innumerable Branches, as it were Roots in the Body of the Liver. The Gall-Bladder is fasten'd to the hollow part thereof, and dischargeth its Choler into the Gut Duodenum, thro' the Vessels that bear the Name of Meatus Choledochi, or Ductus Biliares. This Choler is not a meer Excrement, but on the contrary of singular Use in causing the Fermentation of the Chyle, and bringing it to perfection.
What is the Spleen?
The Spleen is a Bowel resembling a Hart's Tongue in shape, and situated in the Left Hypochondrium, over-against the Liver: Its length is about half a Foot, and its breadth equal to that of three Fingers; its Substance being soft, as that of the Liver, and its Colour like dark coagulated Blood: It is fasten'd to the Peritonæum, Left Kidney, Diaphragm, and to the Caul on the inside; as also to the Stomach by certain Veins, call'd Vasa Brevia; nevertheless these Ligatures do not hinder it from wandering here and there in the lower Belly, where it often changeth its place, and causeth many dreadful symptoms by its irregular Motions. Its Office is to Subtilize the Blood by cleansing and refining it.
What are the Reins?