Micrographia, by Robert Hooke

Observ. xix. Of a Plant growing in the blighted or yellow specks of Damask-rose-leaves, Bramble-leaves, and some other kind of leaves.

I have for several years together, in the Moneths of June, July, August, and September (when any of the green leaves of Roses begin to dry and grow yellow) observ'd many of them, especially the leaves of the old shrubs of Damask Roses, all bespecked with yellow stains; and the undersides just against them, to have little yellow hillocks of a gummous substance, and several of them to have small black spots in the midst of those yellow ones, which, to the naked eye, appear'd no bigger then the point of a Pin, or the smallest black spot or tittle of Ink one is able to make with a very sharp pointed Pen.

scheme12

Schem. 12.
Fig. 2.
Examining these with a Microscope, I was able plainly to distinguish, up and down the surface, several small yellow knobs, of a kind of yellowish red gummy substance, out of which I perceiv'd there sprung multitudes of little cases or black bodies like Seed-cods, and those of them that were quite without the hillock of Gumm, disclos'd themselves to grow out of it with a small Straw-colour'd and transparent stem, the which seed and stem appear'd very like those of common Moss (which I elsewhere describe) but that they were abundantly less, many hundreds of them being not able to equalize one single seed Cod of Moss.

I have often doubted whether they were the seed Cods of some little Plant, or some kind of small Buds, or the Eggs of some very small Insect, they appear'd of a dark brownish red, some almost quite black, and of a Figure much resembling the seed-cod of Moss, but their stalks on which they grew were of a very fine transparent substance, almost like the stalk of mould, but that they seem'd somewhat more yellow.

That which makes me to suppose them to be Vegetables, is for that I perceiv'd many of those hillocks bare or destitute, as if those bodies lay yet conceal'd, as G. In others of them, they were just springing out of their gummy hillocks, which all seem'd to shoot directly outwards, as at A. In others, as at B, I found them just gotten out, with very little or no stalk, and the Cods of an indifferent cize; but in others, as C, I found them begin to have little short stalks, or stems; in others, as D, those stems were grown bigger, and larger; and in others, as at E, F, H, I, K, L, &c. those stems and Cods were grown a great deal bigger, and the stalks were more bulky about the root, and very much taper'd towards the top, as at F and L is most visible.

I did not find that any of them had any seed in them, or that any of them were hollow, but as they grew bigger and bigger, I found those heads or Cods begin to turn their tops towards their roots, in the same manner as I had observ'd that of Moss to do; so that in all likelihood, Nature did intend in that posture, what she does in the like seed-cods of greater bulk, that is, that the seed, when ripe, should be shaken out and dispersed at the end of it, as we find in Columbine Cods, and the like.

The whole Oval OOOO in the second Figure of the 12. Scheme represents a small part of a Rose leaf, about the bigness of the little Oval in the hillock, C, marked with the Figure X. in which I have not particularly observ'd all the other forms of the surface of the Rose-leaf, as being little to my present purpose.

Now, if these Cods have a seed in them so proportion'd to the Cod, as thole of Pinks, and Carnations, and Columbines, and the like, how unimaginably small must each of those seeds necessarily be, for the whole length of one of the largest of those Cods was not 1/500 part of an Inch; some not above 1/1000, and therefore certainly, very many thousand of them would be unable to make a bulk that should be visible to the naked eye; and if each of these contain the Rudiments of a young Plant of the same kind, what must we say of the pores and constituent parts of that?

The generation of this Plant seems in part, ascribable to a kind of Mildew or Blight, whereby the parts of the leaves grow scabby, or putrify'd, as it were, so as that the moisture breaks out in little scabs or spots, which, as I said before, look like little knobs of a red gummous substance.

From this putrify'd scabb breaks out this little Vegetable; which may be somewhat like a Mould or Moss; and may have its equivocal generation much after the same manner as I have supposed Moss or Mould to have, and to be a more simple and uncompounded kind of vegetation, which is set a moving by the putrifactive and fermentative heat, joyn'd with that of the ambient aerial, when (by the putrifaction and decay of some other parts of the vegetable, that for a while staid its progress) it is unfetter'd and left at liberty to move in its former course, but by reason of its regulators, moves and acts after quite another manner then it did when a coagent in the more compounded machine of the more perfect Vegetable.

And from this very same Principle, I imagine the Misleto of Oaks, Thorns, Appletrees, and other Trees, to have its original: It seldom or never growing on any of those Trees, till they begin to wax decrepid, and decay with age, and are pester'd with many other infirmities.

Hither also may be referr'd those multitudes and varieties of Mushroms, such as that, call'd Jews-ears, all sorts of gray and green Mosses, &c. which infest all kind of Trees, shrubs, and the like, especially when they come to any bigness. And this we see to be very much the method of Nature throughout its operations, putrifactive Vegetables very often producing a Vegetable of a much less compounded nature, and of a much inferiour tribe; and putrefactive animal substances degenerating into some kind of animal production of a much inferiour rank, and of a more simple nature.

Thus we find the humours and substances of the body, upon putrifaction, to produce strange kinds of moving Vermine: the putrifaction of the slimes and juices of the Stomack and Guts, produce Worms almost like Earth-worms, the Wheals in childrens hands produce a little Worm, call'd a Wheal-worm: The bloud and milk, and other humours, produce other kinds of Worms, at least, if we may believe what is deliver'd to us by very famous Authors; though, I confess, I have not yet been able to discover such my self.

And whereas it may seem strange that Vinegar, Meal, musty Casks, &c. are observ'd to breed their differing kinds of Insects, or living creatures, whereas they being Vegetable substances, seem to be of an inferiour kind, and so unable to produce a creature more noble, or of a more compounded nature then they themselves are of, and so without some concurrent seminal principle, may be thought utterly unfit for such an operation; I must add, that we cannot presently positively say, there are no animal substances, either mediately, as by the soil or fatning of the Plant from whence they sprung, or more immediately, by the real mixture or composition of such substances, join'd with them; or perchance some kind of Insect, in such places where such kind of putrifying or fermenting bodies are, may, by a certain instinct of nature, eject some sort of seminal principle, which cooperating with various kinds of putrifying substances, may produce various kinds of Insects, or Animate bodies: For we find in most sorts of those lower degrees of Animate bodies, that the putrifying substances on which these Eggs, Seeds, or seminal principles are cast by the Insect, become, as it were, the Matrices or Wombs that conduce very much to their generation, and may perchance also to their variation and alteration, much after the same manner, as, by strange and unnatural copulations, several new kinds of Animals are produc'd, as Mules, and the like, which are usually call'd Monstrous, because a little unusual, though many of them have all their principal parts as perfectly shap'd and adapted for their peculiar uses, as any of the most perfect Animals. If therefore the putrifying body, on which any kind of seminal or vital principle chances to be cast, become somewhat more then meerly a nursing and fostering helper in the generation and production of any kind of Animate body, the more neer it approaches the true nature of a Womb, the more power will it have on the by-blow it incloses. But of this somewhat more in the description of the Water-gnat. Perhaps some more accurate Enquiries and Observations about these matters might bring the Question to some certainty, which would be of no small concern in Natural Philosophy.

But that putrifying animal substances may produce animals of an inferior kind, I see not any so very great a difficulty, but that one may, without much absurdity, admit: For as there may be multitudes of contrivances that go to the making up of one compleat Animate body; so, That some of those coadjutors, in the perfect existence and life of it, may be vitiated, and the life of the whole destroyed, and yet several of the constituting contrivances remain intire, I cannot think it beyond imagination or possibility; no more then that a like accidental process, as I have elswhere hinted, may also be supposed to explicate the method of Nature in the Metamorphosis of Plants. And though the difference between a Plant and an Animal be very great, yet I have not hitherto met with any so cogent an Argument, as to make me positive in affirming these two to be altogether Heterogeneous and of quite differing kinds of Nature: And besides, as there are many Zoophyts, and sensitive Plants (divers of which I have seen, which are of a middle nature, and seem to be Natures transition from one degree to another, which may be observ'd in all her other passages, wherein she is very seldom observ'd to leap from one step to another) so have we, in some Authors, Instances of Plants turning into Animals, and Animals into Plants, and the like; and some other very strange (because unheeded) proceedings of Nature; something of which kind may be met with, in the description of the Water-Gnat, though it be not altogether so direct to the present purpose.

But to refer this Discourse of Animals to their proper places, I shall add, that though one should suppose, or it should be prov'd by Observations; that several of these kinds of Plants are accidentally produc'd by a casual purifaction, I see not any great reason to question, but that, notwithstanding its own production was as 'twere casual, yet it may germinate and produce seed, and by it propagate its own, that is, a new Species. For we do not know, but that the Omnipotent and All-wise Creator might as directly design the structure of such a Vegetable, or such an Animal to be produc'd out of such or such a putrifaction or change of this or that body, towards the constitution or structure of which, he knew it necessary, or thought it fit to make it an ingredient; as that the digestion or moderate heating of an Egg, either by the Female, or the Sun, or the heat of the Fire, or the like, should produce this or that Bird; or that Putrifactive and warm steams should, out of the blowings, as they call them, that is, the Eggs of a Flie, produce a living Magot, and that, by degrees, be turn'd into an Aurelia, and that, by a longer and a proportion'd heat, be transmuted into a Fly. Nor need we therefore to suppose it the more imperfect in its kind, then the more compounded Vegetable or Animal of which it is a part; for he might as compleatly furnish it with all kinds of contrivances necessary for its own existence, and the propagation of its own Species, and yet make it a part of a more compounded body: as a Clock-maker might make a Set of Chimes to be a part of a Clock, and yet, when the watch part or striking part are taken away, and the hindrances of its motion remov'd, this chiming part may go as accurately, and strike its tune as exactly, as if it were still a part of the compounded Automaton. So, though the original cause, or seminal principle from which this minute Plant on Rose leaves did spring; were, before the corruption caus'd by the Mill-dew, a component part of the leaf on which it grew, and did serve as a coagent in the production and constitution of it, yet might it be so consummate, as to produce a seed which might have a power of propagating the same species: the works of the Creator seeming of such an excellency, that though they are unable to help to the perfecting of the more compounded existence of the greater Plant or Animal, they may have notwithstanding an ability of acting singly upon their own internal principle, so as to produce a Vegetable body, though of a less compounded nature, and to proceed so farr in the method of other Vegetables, as to bear flowers and seeds, which may be capabale of propagating the like. So that the little cases which appear to grow on the top of the slender stalks, may, for ought I know, though I should suppose them to spring from the perverting of the usual course of the parent Vegetable, contain a seed, which, being scatter'd on other leaves of the same Plant, may produce a Plant of much the same kind.

Nor are Damask-Rose leaves the onely leaves that produce these kinds of Vegetable sproutings; for I have observ'd them also in several other kinds of Rose leaves, and on the leaves of several sorts of Briers, and on Bramble leaves they are oftentimes to be found in very great clusters; so that I have found in one cluster, three, four, or five hundred of them, making a very conspicuous black spot or scab on the back side of the leaf.

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