der'd more and more fubtile, and fo enabled to enter Veffels ftill finer and finer; the thicker Part of it being at the fame time fecreted and depofited into the lateral Cells or Veficles of the Bark, to defend the Plant from Cold and other external Injuries.

THE Juice (or what is vulgarly call'd the Sap) Of the Sap. having thus gone its Stage from the Root to the remotest Branches, and having, in every Part of its Progrefs, depofited fomething both for Aliment and for Defence, what is redundant paffes out into the Bark, the Veffels whereof are inofculated with those wherein the Sap mounted; and thro' these it re-defcends to the Root, and thence to the Earth again; and thus a Circulation is effected. THE third and laft Part of the Theory of Vege- The Vegetative tation, is a true Knowledge of the vegetative bat. Principle, Principle, or that which is the immediate Matter of the Growth or Increase of the Plant. 'Tis certain this is a Juice furnished by the Earth, and imbib'd by the absorbent Veffels in the Roots of the Plant; this is circulated through the Subftance of the Plant, and, in part, is affimilated thereto: And thus by the conftant Addition of new Matter in every Circulation, the Plant is made to grow or increase its Bulk. But more particularly:

THIS Nutritious Juice is imbibed from the Earth, and therefore muft contain fome Foffil Parts, other Parts derived from Air and Rain, and others from putrified Plants and Animals, &c. and confequently in Vegetables are contained all Kinds of Salts, Oil, Water, Earth, &c. if not mineral Particles too. This Juice enters the Root in form of a fine and fubtile Water,

IN the Root then it is earthy, watry, acid, The State of poor, and scarce oleaginous at all. In the Trunk the Sap in its and Branches it is further prepared, tho' it ftill different Stages

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continues

of Circulation.

The Office of the Sap.

Earth and

but little to the

continues acid. In the Gems or Buds it is more concocted, and, entering the Veffels of the Leaves, causes them to unfold and fhew themfelves. From hence it proceeds to the Leaves of the Flower, where it is ftill further digefted: Thefe tranfmit it to a greater Degree of Fineness to the Stamina; thefe again to the Farina or Duft in the Apices; where, having undergone a further Maturation, it is shed into the Piftil or Style, which receives it in the manner of a Womb, where it acquires its laft Perfection, fæcundates the Seed, and gives Rife to a new Plant.

THE Sap in Plants performs the fame Office as the Blood in Animals, viz. to be a Vehicle to convey the Food or Aliment to the feveral Parts of the Vegetable by Circulation. This Vegetable Aliment is (according to Dr. Woodward) a certain terreftrial Matter contain'd in all Water, and is of two Kinds, viz. The one properly a vegetable Matter, the other of a mineral Nature. The former of these is principally the Matter by which the Vegetable is nourished. That this is more than probable, and that the Plant owes little or nothing of its Growth to Earth or Water, is made evident by divers Experiments.

THUS Mr. Boyle raised a Plant of 3lb. and Water conduce after that another of 14 lb. was produced from a Vegetable Ali- Quantity of Earth water'd with Rain or Springment, fhewn water, and which being carefully weighed dry by Experiat firft and laft, was found to have loft fcarce any thing of its Weight.

ments.

AGAIN; Van Helmont dried 200 lb. of Earth, and therein planted a Willow weighing 5lb. which he water'd with Rain or diftill'd Water only; and after five Years he weighed the Tree, with the Leaves it had born in the time, and found the Weight thereof to be 169 lb. 3 oz. but that the Earth had loft only 2 oz. of its Weight;

fo

fo that the Increase of the Plant was 1313 times more than the Expence of Earth, and confequently Earth has but a fmall Share in Vegetation.

THAT Water likewife conduces but little thereto, is evident from Dr. Woodward's Experiments. He took a Plant of common SpearMint which weighed 27 Grains, and placed it in a Vial of Water for the Space of 77 Days; in which Time it drank up 2558 Grains of Springwater, and then being taken out, weighed 42 Grains; fo that its whole Increase was but 15 Grains, which was but 170th Part of the Water expended.

He took another Plant weighing 127 Grains, placed it in Water for 56 Days, when it weighed 255 Grains, and the Water expended was 14190 Grains, which was 110 times more than the Increase of the Plant. From these, and many other Experiments, 'tis plain that Water also has but a fmall Share in Vegetation, and that there-fore it muft proceed from a peculiar vegetable Matter in Water and the Moisture of the Earth, as before obferved.

SINCE then it appears that Plants imbibe fuch Of the Perfpigreat Quantities of Water or Humour, and re- ration of Plants. tain fo little for Nourifhment and Growth, it follows that there muft neceffarily be a confiderable Perfpiration in Vegetables as well as in Animals, for the Discharge and Evacuation of all the fuperfluous Moisture in each Circulation. Accordingly it has been found by Experience, that a Plant of about 3 lb. will perfpire 30 oz. in 12 Hours Day in July, but in a warm Night not above 30z. and nothing in a cold Night: And also that fuch a Plant, if the Leaves were pluck'd off, would not perfpire above 1 oz. in 12 Hours Day, which plainly fhews that the Leaves are

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the

Of the fecond great Part of

Botany.

the great Organs of Perfpiration, and therefore may be call'd the Lungs of the Plant. Thus much for the Vegetation of Plants, the Theory whereof is not yet arrived to its due Perfection.

THE fecond great Province of Botany, is to make a just and natural Distribution and Arrangement of Vegetables into the feveral Genus's or Kinds and Claffes, and to enumerate the Species and Individuals contain'd in each. To effect this, many Perfons have purfued many and different The Diftribu- Methods. For fince the Kinds of Plants follow tion of Plants. fome general Differences or Characteristics, and thefe being to be found in almoft all Parts of Plants; therefore fome have began to define the various Kinds of Plants from their Roots, others from the Flowers, and others from the Fruit, &c. But in this Affair none has fucceeded fo happily as the great Mr. Ray, whom I fhall here abridge; but fhall first premise a Word or two concerning the more common and general Diftinction of Plants and Vegetables.

Indigenous
Plants.

Exotics.

Male, &c.

FIRST, then, with refpect to Place or Courtry, Plants are diftinguish'd into (1.) Indigenous, or fuch as are Natives of our own Soil or Country; and (2.) Exotics, fuch as are brought from Foreign Countries; as Aloes, Euphorbium, &c. With regard to Sex they are divided into Male, Female, and Hermaphrodite Plants, as before c ferved. With regard to the Time of their Continuance, or Period of Life, they are diftinguifh'd into Annual, or fuch as live but one Year, or come up in the Spring and perish in the Winter; and Perennial, or fuch whofe Roots endure many Years. Again, thofe Plants which retain Evergreens. their Leaves in Winter are call'd Evergreens, Perdifols. and fuch as do not are call'd Deciduous, or Perdifols. Alfo Vegetables have been divided into Herbs, Shrubs, and Trees; but this is rather po

Annual.

Perennial.

pular

pular and vulgar, than just and Philofophical. Laftly, with refpect to the Element they live in, Plants are divided into Terrestrial, or Land- Terreftrial. Plants; Aquatic, or Water-Plants; and Amphi- Aquatic. bious, or fuch as live indifferently in Land or Amphibious. Water.

BUT Mr. Ray is much more minute and nice Mr. Ray's in his celebrated Diftribution of Plants into 25 Diftribution. Genders or Claffes, which are as follow.

I. Submarine Plants, or which grow in the Sea, Submarine. on Rocks, &c. and feem to want both Flower

and Seed: As Corals, Spunges, Alga, &c.

II. THE Fungi, Tubera Terræ, or Mushrooms, Fungous. Puff-Balls, and thofe Excrefcences of Trees call'd Few's-Ear, Agaric, &c. all which appear to want both Flower, and Seed, and Leaves; and have a Vegetation peculiar to themselves.

III. Mofes of all Sorts, moft of which appear Mosses. to want Flower and Seed; for which Reason thefe three Genus's are by Mr. Ray call'd Imperfelt Plants.

IV. Capillary Plants, which are all fuch as Capillaries. want a Stalk, or confift of mere Leaves, and whofe Seed grows like fmall Duft on the Backpart of the Leaves: As Maiden-hair, Spleenwort, Polypody, Fern, &c.

V. Plants which bear apetalous or ftamineous Apetalous. Flowers, i. e. fuch as confift only of Stamina and the Perianthum, without any Leaves: As Hops, Hemp, Nettles, Docks, Sorrel, Arfefmart, Lady'sMantle, &c.

VI. Plants which have a compound Flower, Latiferous.` and which emit a fort of white Juice or Milk, when their Stalks or Branches are cut or broken off: As Lettuce, Sow-Thistle, Dandelion, Succory, Goat's-Beard, Nipplewort, &c.

VII. Plants which have a compound Flower of Difcoide. a Difcoide Figure, and the Seed pappofe, or wing'd

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with