On the structure of the intestinal villi in man and certain of the mammalia, with some observations on digestion, and the absorption of chyle / by John Goodsir.

Date:
[1845]
Catalogue details

Licence: Public Domain Mark

Credit: On the structure of the intestinal villi in man and certain of the mammalia, with some observations on digestion, and the absorption of chyle / by John Goodsir. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    pass off in a radiating direction in the plane of the primary mem- brane, and gradually assuming the form and properties of the epithelium of the region, till they meet and form a continu- ous layer of nucleated particles which cover the primary membrane, from whose nuclei they sprung. These nuclei still remain as sources of future crops of epithelia. During this process of development, the primary membrane would appear to split into two laminae, the epithelia pass- ing out from its nuclei between these. This would account for the epithelia, particularly the prismatic and conical, adher- ing by their free extremities. Such are the processes which would appear to take place in the villi of the intestinal tube during digestion and absorption. When considered in relation to the functions of digestion and absorption of chyle, these processes are highly interesting. The labours of the chemist have now so far simplified the theory of digestion, as to deprive the stomach of their vital- izing or organizing powers so long ascribed to it. Every step in this chemico-physiological inquiry leads to the conclusion that the changes which the food undergoes while in the cavity of the gut are entirely of a chemical m • ture. If we continue, then, to apply the term digestion to that series of processes by which the aliment is assimilated to the matter of which the body is composed, we must divide the se- ries into two groups. The first group will include all those changes which take place within the digestive tube, but ez- terior to the organism. The second will include those which present themselves after the alimentary matter is taken up into the animal body, and becomes buried in its substance. The first group of processes are mechanical and chemical in their nature. They may be considered in a great measure as pe- culiar to the animal, although even vegetables tiirow out from their roots matter which, acting on some of the materials of the surrounding soil, prepare these for absorption. The second group of processes is common to animals and vegetables. In these, for the first time, are alimentary sub- stances taken into the tissues of the organism. In animals, as in plants, as I have already pointed out, these alimentary