122 



A DISCOURSE 



ROOK II. had, of old, recourse to the Robigalia and other Gentile ceremonies : but 

 ^■^'"^r"^ iio longer abused by charmers and superstitious fopperies, we have, in 

 this cliaptcr, endeavoured to set down and prescribe the best and most 

 approved remedies hitherto found out, as well natural as artificial. 



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



cular series outward. The filaments in the flower, which are essential parts in the produc- 

 tion of new plants, are continuations of it. And as the seed-vessels 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 are 

 vessels that carry a juice highly elaborated, the greatest part of which has undergone the 

 concoction of the rinds, blea, and vascular series. The woody fibres constitute an order 

 of vessels, 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 subject 

 to the alternacies of heat and cold. Their use shall be explained hereafter. The pyra- 

 midal vessels are spread through all the substances of the flesh, and, as they advance upwards, 

 their ramifications inosculate, so as to prevent any possible obstruction of the sap. Their 

 juices, as I have observed, are highly elaborated, having passed through all the orders of 

 sap-vessels. It will here be necessary to remark, that the sides of these vessels are con- 

 stantly in contact with the trachea; ; so that, from the nature of their situation, they must, 

 at all times, be subject to the vicissitudes of the weather. The pyramidal vessels com- 

 municate with the pith, which remains to be described. The pith is to be found in all 

 trees, shrubs, and plants. It occupies the centre, but is not always regularly continued. 

 When examined by a microscope, it has the appearance of a number of vesicles, and is of 

 an uniform structure. It does not appear to be absolutely necessary to vegetation, as we 

 often observe Elms, and other trees, to hve and thrive without it. In trees, it is found in 

 the branches, being obliterated in tiie trunk. The vessels of the flesh communicate witli 

 it. From them it receives a fluid; and probably it is the receptacle of some part of the 

 sap. In extreme dry weather such a store may be necessary. Transverse sections of the 

 ribs of leaves discover it. When minutely traced, it is found to run up to the ovarium, 

 where it forms the seeds and 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 variety 

 of strainers, different juices are prepared from the same mass. Matter, considered as 

 matter, has no shai'e in the qualities of bodies. It is from the arrangement of it that we 

 have so many different substances in nature. We may eat the earth, and we may drink 

 the water that moistens it, and yet, from the modification of its parts, it is capable of 

 producing both bread and poison. We reason improperly, when v. e say that every plant 

 takes from the earth sucli particles as are natural to it. A lemon ingrafted upon an 

 orange stock, is capable of changing the sap of the orange into its own nature, by a dif- 

 ferent arrangement of the nutritive juices. A mass of innocent earth can give life and 

 vigour to the bitter aloe, and to the sweet cane ; to the cool house-leek, and to the fiery 



