On food and its digestion: being an introduction to dietetics . scatteredcells; and, by rendering them more refractile, causes acurious contrast of bright spots and darker intervals () on the outer surface of the villus. Gradually, how-ever, the whole of this surface shares in the change. The next step consists in the minute subdivision of thesingle oil-globule now contained in the epithelial details of this (quasi emulsive) process are unknown:but its result is to give the cell a dark granular appear-ance, which a close inspection can distinguish as due toseparate fatty molecul
On food and its digestion: being an introduction to dietetics . scatteredcells; and, by rendering them more refractile, causes acurious contrast of bright spots and darker intervals () on the outer surface of the villus. Gradually, how-ever, the whole of this surface shares in the change. The next step consists in the minute subdivision of thesingle oil-globule now contained in the epithelial details of this (quasi emulsive) process are unknown:but its result is to give the cell a dark granular appear-ance, which a close inspection can distinguish as due toseparate fatty molecules of great minuteness. These mo-lecules are next found in the granular substance of thevillus itself, chiefly near its surface and apex. Fromthence they soon penetrate the central lacteal trunk; 164 DIGESTION. which they sometimes define as a slender column of darkfatty granules. That this process is in part a physical imbibition, canscarcely be doubted. Matteucci and Valentin have provedthat diffusion occurs between a dilute alkaline solution, and Fig. Villus of the Dog about two hours after feeding: showing the entry of fatinto scattered epithelia on its surface. Magnified about 400 diameters. «, a, outline of the villus, formed by epitlielia with their ordinary contents:b, b, epithelia rendered bright and refractile by their fatty contents. a faintly alkaline fatty emulsion, when separated by tissueslike those of an animals bladder. And the circumstancesactually present in the villus are more favourable to sucha transit than those attending the experiments of these oh- ABSORPTION OF FAT. 16o servers. For the alkalinity of the lymph and blood some-times exceeds that of the solution they used. And thescarcely conceivable degree in which the tenuity of the cell-wall of the villus exceeds that of such thick and compoundmembranes as those which form the diffusive partition inthese experiments, would enormously favour the transit ofthe separated fluids. Furthermore, those i
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Keywords: ., bookauthorbrintonw, bookcentury1800, bookdecade1860, bookyear1861
