IN
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IN
INTESTINE MOTION, of tie fart: of thuds. Where the attracting Corpufcles of any Fluid are elaftick, they mutt neceffarily produce an bueftine Motion ; that is, a vi- fible Motion or Change of Place among the minute Parts of a fluid Body : and this greater or lefs according to the Degrees of their Elasticity, and attractive Forces. For two elaltic Particles after meeting will fly from one an- other (abstracting the Refinance of the Medium) with the fame degree of Velocity, with which they met : But when in flying back from one another, they approach other Particles, their Velocity will be increafed. See Elafticity and Fermentation.
INTESTIN ES, in Anatomy, are the fame with what we ordinarily call the Guts or Bowels. Thefe feem to be no- thing but a Continuation of the Stomach, confitKng of the fame Number of Coats, and fabricated in the fame manner; they are protended with various Circumvolutions and Inflex- ions to the /,tms, thro' which they difcharge the excremen- titious part of their Contents out of the body. They are, when feparated from the Mefentery, to which they are all along connected^ of a very great Length, ordinarily about fix times as long as the Perfons whofe they were. And tho they feem to be but one continued Channel or Fiftula, yet becaufe in feveral Parts their Magnitude, Figure, and Thickncfs are different, they are in general divided into the thick and thin, and theft again are each of them fub- divided into three ; the three thin are called Duodenum, Jejunum, and Ileum ; and the thick Geam, Colon, and ReBum. They have all of them in common a kind of Vermicular Motion, which, beginning at the Stomach, is propagated downwards, and is called the Periftaltic Mo- tion. To facilitate that, they are generally lubricated with a great deal of fat, especially the thick ones, whofe Surface being fomewhat more uneven, and the Contents lefs fluid than thofe of the thin, they need fomewhat more to make them Hide eafy.
Thefirftof the rhin Guts iscalled Duodenum, and rea- ches from the right Orifice of the Stomach, as far as the Vertebrx of the Back on the left Side, where, at the firlt Angle made by the Inteftik/Ss it ends, which is about 12 Inches, from which Meafure it feems to have taken its Name. This Meafure however is far from being very exact, as being much too largely computed. Into this Gut the Gall-Duet and Pancreatic- Duct empty themfelves, and their feveral Liquors mix with the Chyle. The next lmeftine is the Jejunum, fo called, becaufe it is generally found more empty than therell ; which may beoccafioned partly by the Fluidity of the Chyle, which is greater in this lmeftine than in any of thofe that follow it ; and partly by its Capacity, being fomewhat larger than that of the Duodenum, and therefore it gives a freer PafTage, and perhaps alio the Irritation of this Gut thro' the Acri- mony of the Bile, which is difcharged upon the Inteftines alittle before the beginning of this Gut, may contribute fomething towards accelerating the PafTage of the Con- tents. However, it may feem Sufficient, that thro' the oreat Number of Lacteals, with which this Gut abounds more than any other, the Defcent of the Contents, which are here deprived of the mofl fluid Parts, Should in the reft be more iluggifh, by reafon of their greater Confiitencc. This Intepme is allowed to pofTcfs almolt the whole Um- bilical Region, and its Length is generally computed to be about twelve or thirteen Hands breadth. The Ileum which is the third lmeftine, is fituatcd below the Navel] and fills the Ilia with its numerous Folds and Convolutions. It is the longefl of all the Inteflines, being efteemed to be one and twenty Hands long : But thefe Eltimates are fomewhat arbitrary, becaufe it is not exaflly fettled a- mong Anatomifts, where the Jejunum ends, or the Ileum begins ; neither is it eafy or ncceffary to do it. In both this and the preceding lmeftine, the Inner Tunic is much corrugated, the loofe Folds of which have been thought to do in fome meafure the Office of Valves, and have therefore by Authors been called VahuU Connhentes ; which are framed, as in the Stomach, only by the inner Coat being larger than the outward.
Next follow the thick Inteftines, the firft of which is called the Cxcum, which has a lateral Infertion into the upper end of the Colon, and is not perforated at its other Extremity, but hangs to it like the Finger of a Glove, and is about three orfour Inches long. The true Ufe of this part is not yet determined, and' fome late Anatomifls have thought that the Name likewife is miflaken, not al- lowing this to be the Qtam of the Anticnts, which they imagined to be that thick globous part of the Colo,,, which is immediately appended to the Ileum, and therefore rhey have given this part the Name of Affendimla Vermiform',;. This Cecum, or Appendix, is proportionably bigger in In- fants than Adults, and in many other Animals even fmal- Jerthan in Men, and is, at the unperforated Extremity Ulghtly connected ,o the right Kidney. The next of the thick Inseftmesis theCb/oa, which is much the largeit, and
mofl capacious of them all. It begins with the Uc,m. and is with that connected to the right Kidney. Thence with a winding Courfe it proceeds towards the Liver, where it is fometimes tied to the Gall-Bladder, and by that tinged with yellow. p> om tl)e L iver it runs a-crofs under the Bottom of the Stomach, where it is by very fine turn Membranes faitned to the Spleen, and marches over the left Kidney, where its Cavity is fometimes very much ftreightned and defending f„ ,0 the bottom of the OjSto<», and from thence returning to the upper part of the Os Sacrum and there making the Figure of a Cir- cumflex, it ends in the ReBum. At the Entrance of the Ileum into this Gut is placed a Valve, formed out of the 1 reduction of the inward Coat of the Ileum, which like the Finger of a Glove, when its Extremity is cut oft", hangs loofe in the Cavity of the Colon, by which means it ftops the return of the Excrements, tho' fometimes as m Inversions ot the Periftaltic Motion, it proves not fuf- ficient for that Ufe. It has a great many CelluU, or, as it were, diftmct Cavities, framed by a Coarftation of the Gut by two Ligaments, or Bundles of membranous flefhy Fibres, about half a Finger broad, each running on either fide the Gut oppofite to each other, the whole Length of it, and as it wete girting it in at certain Diflances, there- by making it referable a Glafs Incorporator, ufed in mixing Oil and Vinegar. The next and lalt of the In- teftines is the ReBum, which reaches from the Os Sacrum to the Amis, and is plain without Cells. It is fall tied to the Offa Sacrum and Coccysris, by means of the Peritoneum, and in Men to the Neck of the Bladder of Urine, in Women to the FapnaVteri, to which it is Strongly connected by a membranous Subflance. That Subflance of the Vttgi- na and Inteftine are hardly diftinguiftiable from one ano- ther. _ The Length of this Gut Is' ordinarily about a hand's Breadth and an half, and its Capacity about the Thick- nefs of three Fingers ; its lower end, the Anus, is fur- mfhed with three Mufcles, mas; the SpbinBer Ami, and Le- vatores Ant 5 which fee.
There are alfo in the Inteftines, a great Number of Glands, which, in the Inteftina tenttia, are gathered together in Heaps, as it were like Bunches of Grapes. In thefe Inteftines they arc very fmall, and were it not for their Coaccrvations, fcarce remarkable. But in the Inteftina CraJ/a they are much larger, not gather- ed like the others, but difperfed ; and, tho' very nil. merous, come under the Denomination of Solitary Glands. Thefe Glands difcharge a Liquor into the Inteftines, whe- ther ordinarily for any thing more than the Lubrication of the Intefth.es, and diluting their Contents, is not cer- tain ; tho' thro' thefe feems the grcatelt patt of the Difcharge to be made, which, cither upon extraordinary Fluxes, or upon the Administration of Cathartics, we have frequent Occafion to ubferve. Thefe Inteftines, in general, are furnilhcd with Blood from the Mefenteric Ar- teries, which is returned by the Meferaic Veins : But the Duodenum receives a Branch of an Artery from the Ce- liac, which is called Duodena, to which anfwers a Vein of the fame Name, that likewife returns the Blood to the Porta ; the ReBum receives others, which arc called Hemor- rhoids ; the internal from the inferior Mefenteric, and the external from theHypogaflric, with Veins corresponding of the fame Name, that alfo go to the Porta. Thefe VeS- fels fpread the Inteftines with abundance of Ramifications, and are frequently diversified in feveral Subjects of the fame Species ; much lefs arc they to be depended upon for an uniform Appearance in Animals of different kind. The Nerves of the Inteftines come fome of them from thofe of the Stomach, and fome from the great Mefenteric Plexus, which distributes Branches to all the Inteftines. The re- maining Vcffels of the Inteftines are the LymphzduBs, and Vcnx LaB.es, which fee.
INTRIGUE, an Affemblage of Events or Circum- ftances occurring in an Affair, and perplexing the Perfons concerned in it. Trifav.d tells us the word is properly un- derstood of Chickens, that have their Feet intangled in Hair, and is derived from the Greek \v and Jlei|.
In this fenfe Intrigue is ufed to Signify the Nodus, or Plot of a Play or Romance, or that Point wherein the principal Characters are the mofl embaratTed, through the Artifice and Opposition of certain Perfons, or the un- fortunate falling out of certain Accidents and Circumstan- ces. In a Tragedy, Comedy, or Epic Poem, there are always two Defigns ; the firii and principal is that of the Hero of the Piece ; the fecond contains the Defigns of all thofe who oppofe him. Thefe oppofite Caufes produce op- pofite Effects, to wit, the Efforts of the Hero for the Execution of his Defign, and the Efforts of thole who thwart it. As thofe Caufes and Defigns are the beginning of the Ac- tion, fo thofe Efforts are the middle, and form a Knot or Difficulty, which we call w Intrigue, that makes the greatest part of the Poem. Itlafisas longastheMind of the Reader or Hearer is fufpended about the Event of thofe oppo- Kkkkk fits
