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Part VI. ANATOMY. 267 colon, and to the contiguous parts of thefe inteftines. nually a kind of mucilage, which not only defends the That on the left fide is fixed to the longitudinal fcifiure internal coat from the acrimony of the fgeces, but ferves of the fpleen, to the extremity of the pancreas, and to alfo to lubricate thefe fseces in proportion to their diffethe convex fide of the great extremity of the ftomach. rent degrees of folidity. It is likewife fixed to the membranous ligament which The inteftinum redtum is the laft refervatory of the fuftains the dudtus cholidochus, and connects it to the feces. The great thicknefs of its mufcular coat, and the great number of longitudinal fibres by which this vena portse ventralis. Below thefe adhefions, the other portions, that is, thicknefs is chiefly formed, enable it to yield to the colthe anterior, pofierior, two lateral and inferior portions, ledted feces to fo great a degree, as to reprefent a large which laft is the bottom of the fucculus epiploicus, have bladder or ftomach. The mufeuli levatores ani ferve to commonly no fixed connections, but lie loofe between the fufpend the lower portion of this inteftine, efpecially fore-fide of the cavity of the abdomen and inteftines. when full; and it is partly by the contradtion of thefe The membrane of the omentum is through, its whole mufcles which overcome the fphindter of the anus, that extent made up of two extremely thin laminas joined by the feces are difeharged out of the body. Thefe fphinca cellular fuftance; the quantity of which is very confi- ters form the third pylorus of the whole alimentary derable along the blood-veffds, which it every where ac- canal. companies in broad bands, proportioned to the branches The mefentery and mefocolon connedt the inteftines, and ramifications of thefe veffels. Thefe cellular bands in fuch a manner, as that they cannot be twifted or run are more or lefs filled with fat according to the corpu- into knots, without hindering them from Hiding and yielding to each other according to the different poftures lency of the fubjedt. Befides this large membranous bag, there is another of the body, or according as they are more or lefs empty much fmaller, which differs from the large one, not on- or full. ly in fize, but alfo in figure, fituation and connexion ; The adhefions of the mefentery form the convolutions and this is the little omentum. This final! bag is of all the fmall inteftines into a large bundle, irregularly fixed by its whole circumference, partly to the fmall round, which fills a great part of the cavity of the abdocurvature of the ftomach, and partly to the concave fide of men, from the epigaftrium downward. the liver before the finus of the vena portae, fo as to fur- The mefocolon by its adhefion to the colon forms a round and contain the prominent portion of the lobulus. kind of feptum tranfverfum, between the fmall inteftines1 The little omentum is thinner and more tranfvarent and the vifcera contained in the epigaftrium; and this fcp than the other, and its cavity diminifhes gradually from turn fupports the liver and'ftomaeh under the arch of the the circumference to the bottom. Its ftrudture is pretty diaphragm, juft as much as it is fuftained by the inteftines; much the fame with that of the great omentum, it be- The breadth of the mefentery and mefocolon affords ing compofed of two laminae, with a niixture of the fame a large extent to the ramifications of the arteries, veins; portions of fat, which are confiderably finer than'in the and nerves, diftributed through them by innumerable other. communications and anaftomofes, by means of which any The fatty appendices of the colon and retftum appear portion of the inteftines may be fupplted, though the to be a kind of fmall omenta or appendices epiploicae. principal branch which leads to it fhould happen to be They are fituated at different diftances along thefe in- compreffed or obftrudted.. teftines, being particular elongations of their common or The cellular fubftance in the duplieature of the mefenexternal coat. They are of the fame ftrudture with the tery and mefocolon, ferves not only for a foft bed to all great omenta, and there is a cellular fubftance contained thefe ramifications, but alfo to contain thofe colle&ions in their duplicature, more or lefs filled with fat, accord- of fat neceffary for the formation of the bile; and the celing as the fubjedt is fat or lean. lular fubftance of, the mefentery has likewife one ufe peculiar to it, which is to invert the lymphatic glands and Jadteal veffels, and upon this account it is thicker than; Uses of the Abdominal Vifcera. that, of the mefocolon. The inteftines in general finifh what the ftomach The ladteal veffels being firft formed by a copious rehad begun.. The alimentary pulp- having been fuffi- ticular texture round the circumference of the inteftines; eiently prepared by the fuccus gaftricus, or lymph of the refembling the vafcular network of that canal, and afterftomach, undergoes a further change by the inteflinal wards uniting every where through the duplicature of the lymph, bile, and pancreatic juice, by which the milky mefentery, with die arterial ramifications which they liquor called chyle is produced, and this liquor rendered likewife accompany in many places ; it is eafy to conceive; fluid enough to enter the ladfeal veffels through the tu- that the pulfation of the mefenteric arteries muft propel nica villofa of the fmall inteftines, while the groffer por- the chyle in the ladteal vefiels from the inteftines to the tion of the aliment continues its courfe, and becoming receptaculum chyli, that motion being fuitable to the db gradually thicker as it advances toward the great inte- redlion of their valves. ftines, is there colledted by the name faces. liver is the principal organ for the fecretion of the The valve of the colon, which might more properly TheThe villi of that immenfe number of glandular be termed fpbintter or pylorus of the ileum, hinders the bile. cells of which it is compofed, filtrate'continually from feces from returning into the fmall infeftines. the blood of the vena portas fmall drops of bile, which The glandular lacunas of the Inteftines.furnifh conti- afterwards infinuate themfclves'into the pori bilarii, an 1 araj
