By the Piece _F_ Plate 6. may be seen, that those Roots cannot penetrate, unless the Land be open’d by Tillage, _&c._ As Animals of different Species have their Guts bearing different Proportions to the Length of their Bodies; so ’tis probable, different Species of Plants may have their Roots as different. But if those which have shorter Roots have more in Number, and having set down the means how to know the Length of them in the Earth, I leave the different Lengths of different Species to be examin’d by those who will take the Pains of more Trials. This is enough for me, that there is no Plant commonly propagated, but what will send out its Roots far enough, to have the Benefit of all the ho’d Spaces or Intervals I in the following Chapters allot them, even tho’ they should not have Roots so long as their Stalks or Stems. And this great Length of Roots will appear very reasonable, if we compare the Largeness of the Leaves (which are the Parts ordain’d for Excretion) with the Smalness of the Capillary Roots, which must make up in Length or Number what they want in Bigness, being destin’d to range far in the Earth, to find out a Supply of Matter to maintain the whole Plant; whereas the chief Office of the Stalks and Leaves is only to receive the same, and to discharge into the Atmosphere such Part thereof as is found unfit for Nutrition; a much easier Task than the other, and consequently fewer Passages suffice, these ending in an obtuse Form; for otherwise the Air would not be able to sustain the Stalks and Leaves in their upright Posture: but the Roots, tho’ very weak and slender, are easily supported by the Earth, notwithstanding their Length, Smalness, and Flexibility. Plants have no Stomach, nor _Oesophagus_, which are necessary to convey the Mass of Food to an Animal: Which Mass, being exhausted by the Lacteals, is eliminated by way of Excrements, but the Earth itself being that Mass to the Guts (or Roots) of Plants, they have only fine Recrements, which are thrown off by the Leaves. In this, Animal and Vegetable Bodies agree, that Guts and Roots are both injured by the open Air; and Nature has taken an equal Care, that both may be supply’d with Nourishment, without being expos’d to it. Guts are supply’d from their Insides, and Roots from their Outsides. All the Nutriment (or _Pabulum_) which Guts receive for the Use of an Animal, is brought to them; but Roots must search out and fetch themselves all the _Pabulum_ of a Plant; therefore a greater Quantity of Roots, in Length or Number, is necessary to a Plant, than of Guts to an Animal. All _Roots_ are as the Intestines of Animals, and have their Mouths or Lacteal Vessels opening on their outer spongy Superficies, as the Guts of Animals have theirs opening in their inner spongy Superficies.