And Earth is so surely the Food of all Plants, that with the proper Share of the other Elements, which each Species of Plants requires, I do not find but that any common Earth will nourish any Plant. The only Difference of Soil[7] (except the Richness) seems to be the different Heat and Moisture it has; for if those be rightly adjusted, any Soil will nourish any Sort of Plant; for let _Thyme_ and _Rushes_ change Places, and both will die; but let them change their Soil, by removing the Earth wherein the _Thyme_ grew, from the dry Hill down into the watry Bottom, and plant _Rushes_ therein; and carry the moist Earth, wherein the _Rushes_ grew, up to the Hill; and there _Thyme_ will grow in the Earth that was taken from the _Rushes_; and so will the _Rushes_ grow in the Earth that was taken from the _Thyme_; so that ’tis only more or less Water that makes the same Earth fit either for the Growth of _Thyme_ or _Rushes_. [7] As I have said in my _Essay_, That _a Soil being once proper to a Species of Vegetables, it will always continue to be so_; it must be supposed, that there be no Alteration of the _Heat_ and _Moisture_ of it; and that this Difference I mean, is of its Quality of nourishing different Species of Vegetables, not of the Quantity of it; which Quantity may be alter’d by Diminution or Superinduction. So for Heat; our Earth, when it has in the Stove the just Degree of Heat that each Sort of Plants requires, will maintain Plants brought from both the _Indies_. Plants differ as much from one another in the Degrees of Heat and Moisture they require, as a Fish differs from a Salamander. Indeed _Misletoe_, and some other Plants, will not live upon Earth, until it be first alter’d by the Vessels of another Plant or Tree, upon which they grow, and therein are as nice in Food as an Animal. There is no need to have Recourse to Transmutation; for whether Air or Water, or both, are transform’d into Earth or not, the thing is the same, if it be Earth when the Roots take it; and we are convinced that neither Air nor Water alone, as such, will maintain Plants. These kind of Metamorphoses may properly enough be consider’d in Dissertations purely concerning Matter, and to discover what the component Particles of Earth are; but not at all necessary to be known, in relation to the maintaining of Vegetables. CHAP. III. _Of_ PASTURE _of_ PLANTS. Cattle feed on Vegetables that grow upon the Earth’s external Surface; but Vegetables themselves first receive, from within the Earth, the Nourishment they give to Animals. The Pasture of Cattle has been known and understood in all Ages of the World, it being liable to Inspection; but the Pasture of Plants, being out of the Observation of the Senses, is only to be known by Disquisitions of Reason; and has (for ought I can find) pass’d undiscover’d by the Writers of Husbandry[8].