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122

A DISCOURSE

book ii. had, of old, recourse to the Robigalia and other Gentile ceremonies: butno longer abused by charmers and superstitious fopperies, we have, inthis chapter endeavoured to set down and prescribe the best and mostapproved remedies hitherto found out, as well natural as artificial.

And first, Weeds are to be diligently pulled up by hand after rain,

cular series outward. The filaments in the flower, which are efsential parts in the produc-tion of new plants, are continuations.of it. And as the seed-vefsels are portions of the

pith, so are the petals and nectaria continuations of the rind, blea, and vascular series;all which the plant shoots outward. Through every part of the wood, or .flesh, there aravefsels that carry a juice highly elaborated, the greatest part of which has undergone theconcoction of the rinds, blea, and vascular series. The woody fibres constitute an orderof vefsels, which are named Tracheae . These are filled with elastic air, and may be dis-covered by the eye, in the wood of all trees. The Tracheae .make up an .arterial system,and supply the place of the heart in animals. Being filled with air, they become subjectto the alternacies of heat aad cold. Their use shall be explained hereafter. The pyra-midal vefsels are spread through all the substance of the flesh, and, as they advance upwards,their ramifications inosculate, so as to prevent any pofsible obstruction of the sap. Theirjuices, as I have observed, are highly elaborated, having pafsed through all the orders ofsap-vefsels. It will here be necefsary to remark, that the sides of these vefsels are con-stantly in contact with the Tracheae ; so that, from the nature of their situation, they must,at all times, be subject to the vicifsitudes of the weather. The pyramidal vefsels com-municate with the pith, which remains to be described. The pith is to be found in alltrees, shrubs, and plants. It occupies the centre, but is not always regularly continued,When examined by a microfcope, it has the appearance of a number of vesicles, and is ofan uniform structure. It does not appear to be absolutely necefsary to vegetation, as weoften observe Elms, and other trees, to live and thrive without it. In trees, it is found inthe branches, being obliterated in the trunk. The vefsels of the flesh communicate withit. From them it receives a fluid; and probably it is the receptacle of some part of thesap. In extreme dry weather such a store may be necefsary. Transverse sections of theribs of leaves discover it. When minutely traced, it is found to run up to the ovarium,where it forms the seeds aud their capsules. From this survey of the anatomy of a plant,it is evident that there is a correspondence between all its parts. By means of a varietyof strainers, different juices are prepared from the same mafs. Matter, considered as.matter, has no share in the qualities of bodies. It is from the arrangement of it that wehave so many different substances in nature. We may eat the earth, and we may drinkthe water that moistens it, and yet, from the modification of its parts, it is capable ofproducing both bread and poison. We reason improperly, when we say that every planttakes from the earth such particles as are natural to it. A Lemon ingrafted upon anOrange stock, is capable of changing the sap of the Orange into its own nature, by a dif-ferent arrangement of the nutritive juices. A mafs of innocent earth can give life andvigour to the bitter Aloe, and to the sweet Cane; to the cool House-Leek, and to the fiery