Page:Cyclopaedia, Chambers - Supplement, Volume 1.djvu/751

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ihe greater! advantage. But before he can expect to arrive at anv true knowledge in this article, it is neceffary that he (hould know what this food or matter of nourishment is. There arc five things generally allowed to contribute to the growth and increafe of plants ; thefe are nitre, water, air, fire and earth ; but it has been much difputed which of all thefe it is that increafes, or is properly thc.Jbod of the plant. Many people fay much of the acid fpirit rdtding in the air, but as this is iharp enough to corrode iron bars it is Coo fharp to be Ht for nourifhing tender plants. As to nitre, it is faid to nourifh them ; but its true office is not aflualy nourifhing, but preparing other things to nourifh them. Nitre applied to the root of a plant will kill it; but at a diftance, fo attenuates, cuts and divides the vifcous matters found in the earth, that after this they are fit to nourifh plants, tho' they were not fo before. Wa- ter has been thought by fome the only food of plants, but Van Helmont's famous experiment, ufually brought to prove this is nothing, for the water contains earth, and therefore is ne- ver given to a plant as water alone.

Air becaufe of its elafticity, is neceffary to the increafe of plants, but it is not that increafe, tho' Bradley and others have taken great pains to prove, that it is fo. As to fire, we are ve- ry well affured indeed, that no plant can live without heat; but tho' different degrees of it, are neceffary to different plants, yet none can live in a£tual fire, nor has fire ever been thought the food of plants except by Mr. Lawrence, and fome of the metaphyficians. This author indeed, fays, plants are true fire- eaters, and others explain away the meaning of the phrafe, by defining that fire to be only the minuteft particles of earth put in motion; if this be the cafe, probably enough the doc- trine may be true. But in plain fa£t, earth alone is the true food and matter of increafe of plants. Every plant is earth, and the growth and increafe of that plant, is only the addi- tion of more earth to it, in the fame form. Nitre and other falts, as thofe of dung, &c. prepare, attenuate, and divide the earth, deftined for the increafe of vegetables ; water and air move it by conveying, and fermenting it in the juices ; but earth itfelf ftill is the food. When the additional earth is once affimilated to the plant, it becomes a part of it, and re- inains for ever with it; but let water, air and heat, be taken away, and the plant remains a plant ftill, tho' a dead one. Midi's Horfehoeing Husbandry, p. 13.

The excefs of the other things, proves, that they are not the proper food of the plant, by deftroying not nourifhing it. Too much nitre or other falts corrode and kill the plant, too much ■water drowns it, too much air dries the roots of it, too much heat burns it: but too much earth a plant never can have, un- lefs wholly buried under it, fo as to exclude the neceffary ac- tion of the reft of the afliftant articles. Too much or too fine earth can never be given to the roots of a plant, for they ne- ver take up fo much of it, as to furfeit the plant, unlets it be deprived of leaves which fhould purify it. Nay earth is fo furely and fo efTentially the food of all plants, that with the proper fbare of the other acceflary elements, any earth, no matter of what kind, will ferve for the nourifhment of any plant.

FOOT (Cvcl.) — Bleeding in the Foot. Bleeding in the foot, is an operation of very old ftanding, and has been ufed by the oldeft phyficians, for diforders of the head and breaft, and for obftruclions of the menftrual, and habitual difcharges by the hemorrhoidal veins. It has been of old fuppofed, that the bleeding from the faphsena was more particularly ferviceable in fome cafes, and from the cephalica in others; but this is now known to be highly erroneous, and the furgeon is always to take that which lies faireft and moft confpicuous. If the veins on the metatarfus or inftep, do not appear fo fairly as might be wifhed, it is common to take one of thofe about the ankle, or the calf of the leg or ham. The patient to be blooded in the foot, muft firft keep botl feet fome time in warm water, that the veins may become turgid, and the furgeon have his choice, which he will take. Having fixed upon the proper foot, the ligature muft be made about two fingers breadth above the ankle, and the patient muff then return the foot into water. The furgeon is to kneel on one knee, and having wiped the foot dry, to put it either againft his other knee, or upon a board placed over the vef- fel of hot water, and the vein muft be held fecure from flipping away, with the left hand, while the orifice is made with the other. If the blood does not flow freely, the foot muft be re- turned into the warm water, till by the colour of the water, ftrength of the patient, &c. it is found to have bled enough. Heijhr's Surgery, p. 280.

Cartilages of fAfFoox. The aftragalus is covered by three car- tilages; the firft covers the furfaces which make the convex part and fides of the pully ; the fecond the concave fur face of i-is inferior part, and the third the convex furface of its ante- rior part, being continued over the inferior part, fo far as to form three other (mall furfaces; one of which is not articular in a Uriel fenfe. The firft of thefe cartilages is for the articu lation of this bone with the tibia and fibula, the fecond for the os calcis, and the third for the os fcaphoides; two of the infe- rior furfaces formed by the continuation of the third cartilage, are for the articulation of this bone with the os calcis ; and the

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third contributes to the formation of a channel for the dailagg of a tendon.

The os calcis has four cartilage?, of which three are fuperiorj one large and two final) for its triple articulation with the aftra- galus ; the fourth is anterior for the os cuboides. And to thefe muft be added a fmall thin cartilage of a kind of ligamentary fubftance, under the tubercle on the outfide of this bone. The os fcaphoides has two cartilages ; one pofterior for its articula- tion with the aftragalus, and one anterior, divided into three parts, for the three offa cuneiformia.

The os cuboides has two remarkable cartilages, one pofterior for its articulation with the os calcis, the other anterior lying in two planes, for its articulation with the two laft metatarfal bones, it has likewife a cartilage .on the infide for the os cunei- forme which is next to it, and one on the lower part, cover- ing an oblique eminence fituated there.

The three offa cuneiformia have each of them a pofterior car- tilage for their articulation with the os fcaphoides, and one an- terior for the three firft metatarfal bones; they have likewife fmall cartilaginous furfaces On their lateral fides for their arti- culations with each other ; and befide, the firft and third bones are joined thereby, to the lateral parts of the bafis of the fecond metatarfal bone, and the third to the os cuboides. The bafes and heads of the metatarfal bones are covered with carti- lages. The phalanges alfo havej in the fame manner, cartila- ges at their bafes and heads, except at the heads or extremi- ties of the laft. The fefamoide bones are covered with car- tilages on that fide, by which they Aide on other bones ; but great caution is required not to confound the remains of ten- dons, ligaments, and aponeuroies with the true cartilages* particularly on the pofterior part of the os calcis. WinflovS^ Anatomy, p. 132, Ligaments of the Foot. The foot being made up of many bones* muft neceffarily befide thofe ligaments, by which it is tied to the bones of the leg, have feveral others to conned not only the three parts of which it is compefed, but alfo the particu- lar bones of each part to one another. In each ankle there are three ligaments for their articulations with the foot. One anterior, one middle, and one pofterior. The ligaments of the inner ankle are all fixed with the infide of the aftragalus ; the anterior and middle ligaments of the outer ankle, arc more or lefs broad and are fixed in the outfide of the aftragalus^ the pofterior which is the narroweft and pretty thick is chiefly fixed in the outfide of the great portion of the os calcis. All thefe ligaments lie on the outfide of the capfula, which fur- rounds the articulation of the aftragalus with the bones of the leg. The ligaments by which the bones of the tarfus are con- nected to one another, are fhort, flat, of different breadths, and run from one hone to another, in oiftercnt directions. Some of thefe are common to feveral bones, and others be- long only to two. The aftiagalus is tied to the other bones of the tarfus by feveral true ligaments ; to the infide of the os calcis, by one which comes from the lateral apophyfis of the os calcis, in an inequality on its hinder part, and is fixed again to the pofterior internal tuberofity of the body of the aftraga- lus, to the outfide of the fame bone, by two ligaments which come from the edge of the oblique inferior depreflion of the aftragalus, and afterwards feparating a little, are fixed in the outfide of the great apophyfis of the os calcis, one forward which feems to fend offa fmall portion to the os cuboides, and the other backward of different breadths ; to the os fcaphoi- des fuperiorly by a ligament, which goes from the neck of the aftragalus, to the upper part of that bone, and from thence is extended to the middle of the os cunciforme, to the fame bone internally by two ligaments, one of which is a continu- ation of that which goes from the lateral apophyfis of the os calcis to the cartilaginous production of the aftragalus; the other is near the fame production, being partly covered by the former, and fixed in the tuberofity of the cs fcaphoides, to the os calcis, by a ligament which comes from the oblique in- ferior depreflion of the aftragalus, and is fixed in the oblique fuperior depreflion of the os calcis; and to thefe the principal ligaments of the aftragalus, feveral fmaller may be added which are ufually feen and increafe the number very greatly. The capfular ligaments go very little farther than the edges of the articulations of this bone with the reft ; they adhere very clofely to the true ligaments, and are covered and hid by them. The os calcis is connected to the os fcaphoides, by a continua- tion of the ligament that goes from its lateral internal apophyfis to thecartilaginousprodu£tion oftheaftragalus,by a ligamentary plane, which goes from its great apophyfis, to the inferior part of the fcaphoides, and by a narrower ligament which goes from the fuperior internal part of its great apophyfis, and ends in the neareft part of the circumference of the fcaphoides. It is connected to the os cuboides, by feveral ligamentary faf- ciculi, which go from its extremity in its fuperior oblique de- preflion, to the contiguous angle of the os cuboides, by one from near the lateral external tuberofity of the os calcis, to a part of the cuboides near the former; by one fixed to the exterior and inferior part of the great tuberofity of the os caicis, to the contiguous part of the cuboides ; by a pretty broad plane, which covers the inferior part of the os calcis, and ends in the ob- lique eminence of the cuboides; and by a broader plane which

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