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Digestion is explain'd by doctor Arbuthnot to be a fermentation begun, because, he says, there are all the requisites of fuch a fermentation, because that requires a greater time than the continuance of the aliment in the stomach. Vegetable putrefaction, for the reasons he gives, resembles very much animal digestion. By mastication, saliva, the attrition of the folid parts, or inward coats, of the stomach, the gall or bile, the pancreatick juice, and the action of a dissolvent liquor, assisted with heat, the aliment is converted into a sort of chyle (a refemblance of milk or whey), and, passing through the mesen ery, is receive'd into the veins, by means of the thoracick duct and the lacteals, becomes finally blood. As the nutriment, therefor, of the body depends entirely on the quantity of chyle, animals, waich take a largeër portion cf aliment by the mouth, may be less nourish'd than those which take a finaller: for, according to the force of the chylopoëtick organs, a largeër or less quantity of chyle may be extracted from the same quantity of food * There is, of course, no essential ditference in the quality of chyle,
* Essay concerning aliments, p. 1, 4, 8, 19, 6c See, allso, doctor Cheynes Natural method of curing diseases, p. 22, &c. * Animal substanceës differ from vegetables in two things: firft, in that being reduced to ashes, they are p:rfectly infipid: all animal falts, being volatile, Aying off with great heat: secondly, in that there is no fincere acid in any animal juice, (P. 64). Animal substanceës, therefor, are all alkalescent; of vegetable subftanceäs, some are acid, other alkalescent, (P. 105).
whether produced by the digestion of animal substanceës, or by that of vegetables, though there may be much in the quančity. * All animals, in fact, are made, immediately or mediately, of vegetables, or of animals that are fed on vegetables; and vegetables, therefor, are proper enough to repair animals, as being nearly of the same specifick gravity with animal substanceës, spirit, water, salt, oil, earth. † Animal substanceës, doctor Arbuthnot ob erves, are more nourishing, and more easeyly transmutable into animal juiceës, than vegetable ; and, therefor, he says, a vegetable diet is more proper for some constitutions, as being less nourishing; though he allows some vegetables, as carrots and turnips, are fattening to animals which live onely on vegetables : and, elsewhere remarks, there may be a stronger broth made of vegetables than any gravy-foup.*
† lli, p. 42.
In the memoirs of the royal academy for the year 1730, M. Geoffroy has giveën a method for determineing the proportion of nourishment, or true matter of the flesh and blood, contain'd in any
sort of food. He took a pound of meat that had been free'd from the fat, bones and cartilageës, and boil'd it for a determine’d time, in a close vessel, with three pints of water; then, pouring off the liquor, he aded the fame quantity of water, boiling it again for the same time, and this operation he repeated six several times, so that the last liquor appear'd, both in smel, trial and taste, to be little different from common water. Then, puting all the liquor together, and filtrateing, to separate the too gross particles, he evaporateëd it over a flow fire, til it was brought to an extrakt of a pretty moderate consistence. This experiment was made upon feveral sorts of food, the result of which is contain’d in the following table :
* Ibi, p. 181, 180.
Yielded of extract
gr. A pound of beef. า ro
8 veal ..
1 48 mutton
I 39 chicken pigeon
8 partridge calves-feet
3 bread .. j L4 According to this table, the proportion of nourishment contain'd in these foods wil be as follows: beef
9 bread $o that common household bread has nearly three times the nutritive quantity of food above any other species.
* Doctor Cheynes Natural method of curing diseases, p. 54. The reflections of M. De Saint-Pierre, respecting the use of bread, become of such abfo. lute necessity over all Europe, may be here subjoin'd: • Who would believe,” he says, “ that it is an aliment of luxury? Of all those which are serve'd up on the table of man, though it be the most common, and even when markets are at the lowest, there is none which costs so dear. The grain of which it is made, is of all vegetable productions, that which demands most culture, machinery and handleing. Before it is cast into the ground, there must be ploughs to til the ground, harrows to break the clods, dunghils to manure it. When it begins to grow, it must be weeded; when come to maturity, the sickle must be employ'd to cut it down ; fails, fanners, bags, barns, to thrash it out, to winnow it, and to store it up; mils to reduce it to flour, to bolt its and to sift it; bake-houseës, where it must be kneaded, leaven'd, bake'd, and converted into bread. Veryly man never could have existed on the earth, had he been under the necessity of deriveing his first nutriment from the corn plant. It is no where found indigenous. Nay, its grain, from the form and size, appears much better adapted to the beak of granivorous birds than to the mouth of man. Not so much as the twentyeth part of mankind eats bread. Allmost all the