A DISCOimSE 



and if this be true and constant, all our imbibitions of salts and composts 

 signify little to earth pre-impregnated with a salt or virtue different from 

 what the plant does naturally delight in, some obscure footsteps of which 

 every ploughman seems to discover, which makes him change tlie crop 

 in some places yearly. For the first, second, or third burden of the same 

 gi'ain, especially wheat, will exhaust that which is its proper aliment, 

 and then leave the rest to more ignoble grain, which will be found to 

 thrive well enough, till at last several successions of different seeds quite 

 wear it out, and then the land must repose, or be manured with composts 

 for fresh life and vigour And to this we may add, how some plants again 

 require little change or help of art ; such as most of the perennial greens, 

 and amongst these, the most resinous and oily, as the Pine, Fir, Cedar, &;c. 

 which thrive on barren hills, and grow in rocky crannies, without any 

 earth almost to cover and protect their roots. Of this sort I have a Cedar 

 table, which was sawed out of a spur only, of a monstrous tree growing 

 in Barbadoes, which held six feet long, five feet broad, and three inches 

 thick, formed and wrought as it stands upon the frame ; and his royal 

 highness had another of a much larger dimension, namely, eighteen 

 feet in length, and nine in breadth, cut out of the stem, which was 

 of prodigious growth, fed and nourished as it was between the barren 



Hoc e fonte fluit, me judice, fabula Graium ; 



Haec olim seripedes tauri^ vigilesque dracones / 

 Vellera servavere, hac ibat dote per undas 

 Medea, his visus renovari fructibus iEson, 



Et succo preesente senex revocasse juventam." Conndb. Floh. 



^ It does not seem a well-founded opinion, that plants of different kinds select different 

 particles from the same earth. Accurate experiments rather prove that they all live upon 

 the same general food. Some require more, some less. Some take it near the surface, 

 others take it deeper. Upon these principles we may rationally account for the necessity of 

 changing the species in the old husbandry. With regard to the different tastes and odours 

 of different plants growing upon the same bed of earth, I shall only remark, that the modi- 

 fication of the particles of the general nutriment produces all the differences. Matter, con- 

 sidered as matter, has no share in the qualities of bodies. It is from the arrangement of 

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

 that moistens it, and yet from the modification of its parts by the different vessels of plants, 

 it is capable of becoming both bread and poison. A lemon, grafted upon an orange stock, 

 is capable of changing the sap of the orange into its own nature, by a different arrange- 

 ment of the nutritive juices. The same mass of innocent earth can give life and vigour to 

 the bitter aloe, and to the sweet cane ! to the cool houseleek, and to the fiery mustard! to 

 the nourishing grains, and to the deadly nightshade ! 



