Another use is for Augmentation; or, the capacity for the due spreading and ampliation of a Tree or Plant, are its Leaves: For the _Lignous Body_ being divided into small Fibres, and these running all along their lax and spongie _Parenchyma_; they are thus a Body fit for the imbibition of _Sap_ and easie growth. Now the _Sap_ having a free reception into the Leaves, it still gives way to the next succeeding in the _Branches_ and _Trunk_, and the voyding of the _Sap_ in these, for the mounting of that in the _Root_, and ingress of that in the Mould. But were there no Leaves to make a free reception of _Sap_, it must needs be stagnant in all the parts to the _Root_, and so the _Root_ being clogg’d, its fermenting and other Offices will be voyded, and so the due growth of the whole. As in the motion of a Watch, although the original term thereof be the Spring, yet the capacity for its continuance in a due measure throughout all the Wheels, is the free and easie motion of the Ballance. Lastly, As the Leaves subserve the more copious advancement, so the higher purity of the _Sap_: For this being well fermented both in the Root, and in its Ascent through the _Trunk_, and so its Parts prepar’d to a farther separation; the grosser ones are still deposited into the Leaves; the more elaborate and essential only thus supplied to the _Flower_, _Fruit_ and _Seed_, as their convenient Aliment. Whence it is, that where the _Flowers_ are many and large, into which the more odorous Particles are copiously receiv’d, the green Leaves have little or no smell; as those of _Rose-tree_, _Carnations_, _French-Marigold_, _Wood-bind_, _Tulips_; &c. But on the contrary, where the Flowers are none or small, the green Leaves themselves are likewise of a strong savour; as those of _Wormwood_, _Tansie_, _Baum_, _Mint_, _Rue_, _Geranium Moschatum_, _Angelica_, and others. _An Appendix._ _Of Thorns, Hairs and Globulets._ _Thorns_ are of two kinds, _Lignous_ and _Cortical_. Of the first are such as those of the _Hawthorn_, and are constituted of all the same substantial Parts whereof the _Germen_ it self, and in a like proportion: which also in their Infancy are set with the resemblances of divers minute Leaves. In affinity with these are the _Spinets_ or _Thorny Prickles_ upon the Verges and Tops of divers Leaves, as of _Barberry_, _Holly_, _Thistle_, _Furze_, and others; all which I think are the filamentous extremities of the _Lignous Body_ sheathed in the _Skin_. _Cortical Thorns_ are such as those of the _Rasberry_ Bush, being not, unless in a most extraordinary small proportion propagated from the _Lignous Body_, but almost wholly from the _Cortical_ and _Skin_, or from the _Barque_.