On food and its digestion: being an introduction to dietetics . of thedomestic animals. Grruby and Delafomi are confirmedby Bruecke and Koelliker in their observation, under thesecircumstances, of an alternate shortening: and lengtheningof the villus : a change so rapid and marked, as to bedoubtless due to a corresponding contraction and re-laxation of these its unstriped fibres. But the phenomenaof such vivisections cannot safely be accepted as those ofthe natural state. Such a caution is still more applicable to the contractionsby which the villi share in that irregular intestinal move-ment—
On food and its digestion: being an introduction to dietetics . of thedomestic animals. Grruby and Delafomi are confirmedby Bruecke and Koelliker in their observation, under thesecircumstances, of an alternate shortening: and lengtheningof the villus : a change so rapid and marked, as to bedoubtless due to a corresponding contraction and re-laxation of these its unstriped fibres. But the phenomenaof such vivisections cannot safely be accepted as those ofthe natural state. Such a caution is still more applicable to the contractionsby which the villi share in that irregular intestinal move-ment—a kind of rigor mortis—already (p. 139) described. COXTKACTIOXS OF VILLI. 161 Exposed immediately after death, they gradually becomeshorter and wider; while their surface is usually throwninto transverse wrinkles and folds. Transmitted lightshows these folds to consist of the epithelial layer, whichhas separated from the basement membrane at the pro-jections between adjacent wrinkles. Sometimes the ad-Fig. 25. |M»»»«:sH5iji;i III*; • s.:::M !• lm. Villi contracted and shortened so as to offer circular or transverse the small intestine of the Dog shortly after death. Magnified 100diameters ; and examined by reflected light. hesion of the same layer to the free end of the villusforms, at this point, a kind of shallow funnel, which isbounded by the neighbouring separated cells. In otherinstances, the free end of the villus is withdrawn from its M 162 DIGESTION. epithelial investment by the contraction of its muscularlayer so uniformly, as to leave the whole of the cell-growth covering this part uninjured, smooth, and empty,like the finger of a glove. Often, however, a few cellsare here and there detached. Fig. 26. B
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Keywords: ., bookauthorbrintonw, bookcentury1800, bookdecade1860, bookyear1861
