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Among the different articles of diet, fleshmeat was constantly digested with most ease. and expedition. Eggs and cheese-it is not said what kind of cheese-were very quickly digested. Vegetables in general were much longer in undergoing this process. But potatoes, cucumbers! and carrots soonest passed into the intestines.

But coagulation and solution are by no means the whole of digestion. A great deal more preparation is necessary to provide for repairing the waste of the body. The succession of steps may be compared to a very complicated manufactory, where the material, before it can attain the necessary perfection, passes through the hands of a multitude of artisans, each of whom, in his department, must do justice to the fabric; or else the whole labour will be as good as lost. What happens further to the solution in the gastric liquor is very obscurely known. It is undoubtedly propelled through the lower orifice of the stomach into the intestines in proportion as the solution is completed. In the first intestine, the bile and the pancreatic juice and the liquids, secreted by the intestine, are gradually mixed with it. But the effect of this mixture no one has ascertained. The addition of the bile is not necessary to

the main purpose of digestion. For the formation of chyle (or of that fluid which replaces the blood, as it is consumed in feeding the various solid parts of the body) would appear clearly independant of the bile; since the access of the bile having been artificially prevented, chyle was nevertheless found in its proper receptacles. The same thing has been ascertained with regard to the pancreatic juice, which, in ordinary circumstances, flows into the duodenum to be mixed with the substances that have undergone solution in the stomach, the full discovery of which step by SPALLANZANI, is by far the most considerable, hitherto made on the subject of digestion.

The only way we have of attaining any thing like a satisfactory notion concerning what happens to the alimentary mass, after it has been dissolved, is to consider the nature of animal and vegetable substances. These substances appear to be in general distinguished from inorganic bodies by their susceptibility of change. Their elements may be considered as united in a manner peculiarly loose, and as ready, on the smallest provocation, to start into new combinations. An apple or a piece of flesh placed in a temperature, too low to have any ascertainable

effect on a pebble shall be altered in its taste, consistence and whole constitution. Some of the elements, after undergoing new combinations, shall be given out in the form of air; some in a liquid state; and the remainder shall be unlike any thing the body contained at first. The alterations shall be different in a temperature some degrees below the ordinary temperature of the atmosphere from those which take place some degrees below it, or in a degree of cold sufficient to freeze the juices. In short, there will be a sensible. variation of product, correspondent to variations of circumstances, apparently very trivial. Organised bodies, the matter of aliment, have a very complicated as well as a very changeable composition. Hence they yield great variety of products. Held in solution in the gastric juice-having other juices of various quality gradually added to them from the interior surfaces of the intestines--acted upon by the heat of the bodyand perhaps influenced by the living membranes in some unknown way, remotely analogous to the effect of the metals in the galvanic pile, their disunited floating particles assume an arrangement, which art has not yet acquired the power to imitate, and form chylea milky matter, consisting, when it

is taken out of the vessels, of a fluid, which coagulates spontaneously, of another fluid coagulable by heat, and of white globules, that give the whole its whiteness and opacity.

The principal means by which DIGESTION is impaired, and the DIGESTIVE ORGANS injured.

All the materials therefore which are capable of serving for food must have one

common property. principles of chyle. easy to bring some their elements will coalesce into that particular species of fluid.-Hence we learn the task imposed upon the stomach and its appendages. By them it is necessary that the agents, on which the several steps in the transmutation of food into chyle depend, should be supplied from day to day in sufficient quantity, and possess the requisite qualities. Otherwise the whole system will languish for want of a renovation of that part of its substance which is continually wasted, and the region of the stomach will be the seat of a perpetual succession of nameless, harrassing sensations, rendering existence cheerless, and afterwards by means of certain associations,

Each must contain the Though it may be more into the state, in which

as we shall presently see, becoming scarcely supportable.

If the chyle be the fountain of the blood, the blood is the fountain of the juices, instrumental in the preparation of the chyle. The blood must not only furnish to the secretory organs the elements of these juices, but it must circulate through them with a certain degree of vigour. No fact belonging to animal nature is proved by a greater number of examples than both the permanent and occasional connection between exertions attended by a vigorous circulation of the blood, and a keen appetite with a correspondent digestion. Not only do those occupations produce a contrary effect, which are carried on in a posture, unfavourable to a free expansion of the stomach, as weaving, but those also that scarce allow more range of motion than the oyster enjoys, though there be nothing injurious in the posture.

Who would not desire to have an accurate acquaintance with the substances, especially if there be any in common use, which impair the coagulating or solvent powers? We cannot make direct observations upon the interior of the human stomach; but we have animals, very closely resembling man in having a single and equally thin stomach, and in

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