If any one of these Three Propositions be true, as I hope to prove all of them are, then it will follow, that there is no need to change the Species of Vegetables from one Year to another, in respect to the different Food the same Soil is, tho’ falsely, supposed to yield[201].
[201]For if all Plants rob one another, it must be because they all feed on the same Sort of Food; and, admitting they do, there can be no Necessity of changing the Species of them, from one Soil to another; but the same Quantity of the same Food, with the same Heat and Moisture which maintains any Species one Year, must do it any other Year.
The common Opinion is contrary to all these (as it must be, if contrary to any one of them): And since an Error in this fundamental Principle of Vegetation is of very ill Consequence; and since Dr. Woodward, who has been serviceable in other respects[202] to this Art, has unhappily fallen in with the Vulgar in this Point; his Arguments for this Error require to be answer’d in the first Place.
[202]By proving, in his Experiments, that Earth is the Pabulum of Plants.
The Doctor says[203] ‘It is not possible to imagine how one uniform, homogeneous Matter, having its Principles, or original Parts, all of the same Substance, Constitution, Magnitude, Figure, and Gravity, should ever constitute Bodies so egregiously unlike, in all those Respects, as Vegetables of different Kinds are; nay, even as the different Parts of the same Vegetable.’
[203]In Philos. Trans. No. 253.
‘That there should be that vast Difference in them, in their several Constitutions, Makes, Properties, and Effects, and yet all arise from the very same Sort of Matter, would be very strange.’
Answer. ’Tis very probable, that the terrestrial Particles which constitute Vegetables, tho’ inconceivably minute, may be of great Variety of Figure, and other Differences; else they could not be capable of the several Ferments, &c. they must undergo in the Vessels of Plants. Their Smalness can be no Objection to their Variety, since even the Particles of Light are of various Kinds.
But as the Doctor asserts, ‘That each Part of the same Vegetable requires a peculiar specific Matter for its Formation and Nourishment; and that there are very many and different Ingredients to go to the Composition of the same individual Plants;’
From hence must be inferred, that the same Plant takes in very many and different Ingredients (and it is proved, that no Plant refuses any Ingredient[204] that is capable of entering its Roots. Tho’ the terrestrial Particles which nourish Vegetables, be not perfectly homogeneous; yet most of the various Tastes and Flavours of Plants are made in and by the Vessels[205].