But to digress no further, we may, from this discovery of the _Microscope_, plainly enough understand how the skin, though it looks so close as it does, comes to give a passage to so vast a quantity of _excrementitious_ substances, as the diligent _Sanctorius_ has excellently observed it to do, in his _medicina statica_; for it seems very probable, from the texture after dressing, that there are an infinite of pores that every way pierce it, and that those pores are onely fill’d with some kind of juice, or some very pulpy soft substance, and thereby the steams may almost as easily find a passage through such a fluid _vehicle_ as the vaporous bubbles which are generated at the bottom of a Kettle of hot water do find a passage through that fluid _medium_ into the ambient Air. Nor is the skin of animals only thus pervious, but even those of vegetables also seem to be the same; for otherwise I cannot conceive why, if two sprigs of Rosemary (for Instance) be taken as exactly alike in all particulars as can be, and the one be set with the bottom in a Glass of water, and the other be set just without the Glass, but in the Air onely, though you stop the lower end of that in the Air very carefully with Wax, yet shall it presently almost wither, whereas the other that seems to have a supply from the subjacent water by its small pipes, or _microscopical_ pores, preserves its greenness for many days, and sometimes weeks. Now, this to me, seems not likely to proceed from any other cause then the _avolation_ of the juice through the skin; for by the Wax, all those other pores of the stem are very firmly and closely stop’d up. And from the more or less porousness of the skins or rinds of Vegetables may, perhaps, be somewhat of the reason given, why they keep longer green, or sooner wither; for we may observe by the bladdering and craking of the leaves of Bays, Holly, Laurel, &c. that their skins are very close, and do not suffer so free a passage through them of the included juices. But of this, and of the Experiment of the Rosemary, I shall elsewhere more fully consider, seeming to me an extreme luciferous Experiment, such as seems indeed very plainly to prove the _Schematism_ or structure of Vegetables altogether _mechanical_, and as necessary, that (water and warmth being apply’d to the bottom of the sprig of a Plant) some of it should be carried upwards into the stem, and thence distributed into the leaves, as that the water of the _Thames_ covering the bottom of the Mills at the Bridge foot of _London_, and by the ebbing and flowing of it, passing strongly by them, should have some part of it convey’d to the Cesterns above, and thence into several houses and Cesterns up and down the City. * * * * * Observ. XXXIII. _Of the _Scales_ of a _Soal_, and other Fishes._