Micrographia, by Robert Hooke

Observ. xliii. Of the Water-Insect or Gnat.

This little creature, described in the first Figure of the 27. Scheme, Schem. 27.
Fig. 1.
was a small scaled or crusted Animal, which I have often observ'd to be generated in Rain-water; I have also observ'd it both in Pond and River-water. It is suppos'd by some, to deduce its first original from the putrifaction of Rain-water, in which, if it have stood any time open to the air, you shall seldom miss, all the Summer long, of store of them frisking too and fro.

'Tis a creature, wholly differing in shape from any I ever observ'd; nor is its motion less strange: It has a very large head, in proportion to its body, all covered with a shell, like other testaceous Animals, but it differs in this, that it has, up and down several parts of it, several tufts of hairs, or brisles, plac'd in the order express'd in the Figure; It has two horns, which seem'd almost like the horns of an Oxe, inverted, and, as neer as I could guess, were hollow, with tufts of brisles, likewise at the top; these horns they could move easily this or that way, and might, perchance, be their nostrils. It has a pretty large mouth, which seem'd contriv'd much like those of Crabs and Lobsters, by which, I have often observ'd them to feed on water, or some imperceptible nutritive substance in it.

I could perceive, through the transparent shell, while the Animal surviv'd, several motions in the head, thorax, and belly, very distinctly, of differing kinds which I may, perhaps, elsewhere endeavour more accurately to examine, and to shew of how great benefit the use of a Microscope may be for the discovery of Nature's course in the operations perform'd in Animal bodies, by which we have the opportunity of observing her through these delicate and pellucid teguments of the bodies of Insects acting according to her usual course and way, undisturbed, whereas, when we endeavour to pry into her secrets by breaking open the doors upon her, and dissecting and mangling creatures whil'st there is life yet within them, we find her indeed at work, but put into such disorder by the violence offer'd, as it may easily be imagin'd, how differing a thing we should find, if we could, as we can with a Microscope in these smaller creatures, quietly peep in at the windows, without frighting her out of her usual byas.

The form of the whole creature, as it appear'd in the Microscope, may, without troubling you with more descriptions, be plainly enough perceiv'd by the Scheme, the hinder part or belly consisting of eight several jointed parts, namely, ABCDEFGH, of the first Figure, from the midst of each of which, on either side issued out three or four small brisles or hairs, I, I, I, I, I, the tail was divided into two parts of very differing make; one of them, namely, K, having many tufts of hair or brisles, which seem'd to serve both for the finns and tail, for the Oars and Ruder of this little creature, wherewith it was able, by frisking and bending its body nimbly to and fro, to move himself any whither, and to skull and steer himself as he pleas'd, the other part, L, seem'd to be, as 'twere, the ninth division of his belly, and had many single brisles on either side. From the end V, of which, through the whole belly, there was a kind of Gut of a darker colour, MMM, wherein, by certain Peristaltick motions there was a kind of black substance mov'd upwards and downwards through it from the orbicular part of it, N, (which seem'd the Ventricle, or stomach) to the tail V, and so back again, which peristaltick motion I have observ'd also in a Louse, a Gnat, and several other kinds of transparent body'd Flies. The Thorax or chest of this creature OOOO, was thick and short, and pretty transparent, for through it I could see the white heart (which is the colour also of the bloud in these, and most other Insects) to beat, and several other kind of motions. It was bestuck and adorn'd up and down with several tufts of brisles, such as are pointed out by P, P, P, P, the head Q was likewise bestuck with several of those tufts, SSS; it was broad and short, had two black eyes, TT, which I could not perceive at all pearl'd, as they afterwards appear'd, and two small horns, RR, such as I formerly describ'd.

Both its motion and rest is very strange, and pleasant, and differing from those of most other creatures I have observ'd; for, where it ceases from moving its body, the tail of it seeming much lighter then the rest of its body, and a little lighter then the water it swims in, presently boys it up to the top of the water, where it hangs suspended with the head always downward; and like our Antipodes, if they do by a frisk get below that superficies, they presently ascend again unto it, if they cease moving, until they tread, as it were, under that superficies with their tails; the hanging of these in this posture, put me in mind of a certain creature I have seen in London, that was brought out of America, which would very firmly suspend it self by the tail, with the head downwards, and was said to keep in that posture, with her young ones in her false belly, which is a Purse, provided by Nature for the production, nutrition, and preservation of her young ones, which is described by Piso in the 24. Chapter of the fifth Book of his Natural History of Brasil.

The motion of it was with the tail forwards, drawing its self backwards, by the striking to and fro of that tuft which grew out of one of the stumps of its tail. It had another motion, which was more sutable to that of other creatures, and that is, with the head forward; for by the moving of his chaps (if I may so call the parts of his mouth) it was able to move it self downwards very gently towards the bottom, and did, as 'twere, eat up its way through the water.

But that which was most observable in this creature, was, its Metamorphosis or change; for having kept several of these Animals in a Glass of Rain-water, in which they were produc'd, I found, after about a fortnight or three weeks keeping, that several of them flew away in Gnats, leaving their husks behind them in the water floating under the surface, the place where these Animals were wont to reside, whil'st they were inhabitants of the water: this made me more diligently to watch them, to see if I could find them at the time of their transformation; and not long after, I observ'd several of them to be changed into an unusual shape, wholly differing from that they were of before, their head and body being grown much bigger and deeper, but not broader, and their belly, or hinder part smaller, and coyl'd, about this great body much of Schem. 27.
Fig. 2.
the fashion represented by the prick'd line in the second Figure of the 27. Scheme, the head and horns now swam uppermost, and the whole bulk of the body seem'd to be grown much lighter; for when by my frighting of it, it would by frisking out of its tail (in the manner express'd in the Figure by BC) sink it self below the surface towards the bottom; the body would more swiftly re-ascend, then when it was in its former shape.

I still marked its progress from time to time, and found its body still to grow bigger and bigger, Nature, as it were, fitting and accoutring it for the lighter Element, of which it was now going to be an inhabitant; for, by observing one of these with my Microscope, I found the eyes of it to be altogether differing from what they seem'd before, appearing now all over pearl'd or knobb'd, like the eyes of Gnats, as is visible in the second Figure by A. At length, I saw part of this creature to swim above, and part beneath the surface of the water, below which though it would quickly plunge it self if I by any means frighted it, and presently re-ascend into its former posture; after a little longer expectation, I found that the head and body of a Gnat, began to appear and stand cleer above the surface, and by degrees it drew out its leggs, first the two formost, then the other, at length its whole body perfect and entire appear'd out of the husk (which it left in the water) standing on its leggs upon the top of the water, and by degrees it began to move, and after flew about the Glass a perfect Gnat.

I have been the more particular, and large in the relation of the transformation of divers of these little Animals which I observ'd, because I have not found that any Authour has observ'd the like, and because the thing it self is so strange and heterogeneous from the usual progress of other Animals, that I judge it may not onely be pleasant, but very usefull and necessary towards the compleating of Natural History.

There is indeed in Piso, a very odd History, which this relation may make the more probable; and that is in the 2. Chapter of the 4. Book of his Natural History of Brasil, where he says, Porro præter tot documenta fertilitatis circa vegetabilia & sensitiva marina telluris æmula, accidit & illud, quod paucis à Paranambucensi milliaribus, piscatoris uncum citra intentionem contingat infigi vadis petrosis, & loco piscis spongia, coralla, aliasque arbusculas marinas capi. Inter hæc inusitatæ formæ prodit spongiosa arbuscula sesquipedis longitudinis, brevioribus radicibus, lapideis nitens vadis, & rupibus infixa, erigiturque in corpus spongiosum molle oblongum rotundum turbinatum: intus miris cancellis & alveis fabricatum, extus autem tenaci glutine instar Apum propolis undique vestitum, ostio satis patulo & profundo in summitate relicto, sicut ex altera iconum probe depicta videre licet (see Schem. 27.
Fig. 3. & 4.
the third and fourth Figures of the 27. Scheme.) Ita ut Apiarium marinum vere dixeris; primo enim intuitu è Mare ad Terram delatum, vermiculis scatebat cæruleis parvis, qui mox à calore solis in Muscas, vel Apes potius, easq; exiguas & nigras transformebantur, circumvolantesque evanescebant, ita ut de eorum mellificatione nihil certi conspici datum fuerit, cum tamen cærosa materia propolis Apumque cellæ manifeste apparerent, atque ipsa mellis qualiscunque substantia proculdubio urinatoribus patebit, ubi curiosius inquisiverint hæc apiaria, eaque in natali solo & salo diversis temporibus penitius lustrarint.

Which History contains things sufficiently strange to be consider'd, as whether the husk were a Plant, growing at the bottom of the Sea before, of it self, out of whose putrifaction might be generated these strange kind of Magots; or whether the seed of certain Bees, sinking to the bottom, might there naturally form it self that vegetable hive, and take root; or, whether it might not be placed there by some diving Fly; or, whether it might not be some peculiar propriety of that Plant, whereby it might ripen or form its vegetable juice into an Animal substance; or, whether it may not be of the nature of a Sponge, or rather a Sponge of the nature of this, according to some of those relations and conjectures I formerly made of that body, is a matter very difficult to be determined. But indeed, in this description, the Excellent Piso has not been sufficiently particular in the setting down the whole process, as it were to be wish'd: There are indeed very odd progresses in the production of several kinds of Insects, which are not less instructive then pleasant, several of which, the diligent Goedartius has carefully observ'd and recorded, but among all his Observations, he has none like this, though that of the Hemerobius be somewhat of this kind, which is added as an Appendix by Johannes Mey.

I have, for my own particular, besides several of those mention'd by him, observ'd divers other circumstances, perhaps, not much taken notice of, though very common, which do indeed afford us a very coercive argument to admire the goodness and providence of the infinitely wise Creator in his most excellent contrivances and dispensations. I have observ'd, at several times of the Summer, that many of the leaves of divers Plants have been spotted, or, as it were scabbed, and looking on the undersides of those of them that have been but a litte irregular, I have perceiv'd them to be sprinkled with divers sorts of little Eggs, which letting alone, I have found by degrees to grow bigger, and become little Worms with leggs, but still to keep their former places, and those places of the leaves, of their own accords, to be grown very protuberant upwards, and very hollow, and arched underneath, whereby those young creatures are, as it were, shelter'd and housed from external injury; divers leaves I have observ'd to grow and swell so farr, as at length perfectly to inclose the Animal, which, by other observations I have made, I ghess to contain it, and become, as it were a womb to it, so long, till it be fit and prepar'd to be translated into another state, at what time, like (what they say of) Vipers, they gnaw their way through the womb that bred them; divers of these kinds I have met with upon Goosberry leaves, Rose-tree leaves, Willow leaves, and many other kinds.

There are often to be found upon Rose-trees and Brier bushes, little red tufts, which are certain knobs or excrescencies, growing out from the Rind, or barks of those kinds of Plants, they are cover'd with strange kinds of threads or red hairs, which feel very soft, and look not unpleasantly. In most of these, if it has no hole in it, you shall find certain little Worms, which I suppose to be the causes of their production; for when that Worm has eat its way through, they, having performed what they were design'd by Nature to do, by degrees die and wither away.

Now, the manner of their production, I suppose to be thus, that the Alwise Creator has as well implanted in every creature a faculty of knowing what place is convenient for the hatching, nutrition, and preservation of their Eggs and of-springs whereby they are stimulated and directed to convenient places, which becom, as 'twere the wombs that perform those offices: As he has also suited and adapted a property to those places wherby they grow and inclose those seeds, and having inclosed them, provide a convenient nourishment for them, but as soon as they have done the office of a womb, they die and wither.

The progress of inclosure I have often observ'd in leaves, which in those places where those seeds have been cast, have by degrees swell'd and inclos'd them, so perfectly round, as not to leave any perceptible passage out.

From this same cause, I suppose that Galls, Oak-apples, and several other productions of that kind, upon the branches and leaves of Trees, have their original, for if you open any of them, when almost ripe, you shall find a little Worm in them. Thus, if you open never so many dry Galls, you shall find either a hole whereby the Worm has eat its passage out, or if you find no passage, you may, by breaking or cutting the Gall, find in the middle of it a small cavity, and in it a small body, which does plainly enough yet retain a shape, to manifest it once to have been a Worm, though it dy'd by a too early reparation from the Oak on which it grew, its navel-string, as 'twere, being broken off from the leaf or branch by which the Globular body that invelop'd it, received its nourishment from the Oak.

And indeed, if we consider the great care of the Creator in the dispensations of his providences for the propagation and increase of the race, not onely of all kind of Animals, but even of Vegetables, we cannot chuse but admire and adore him for his Excellencies, but we shall leave off to admire the creature, or to wonder at the strange kind of acting in several Animals, which seem to favour so much of reason; it seeming to me most manifest, that those are but actings according to their structures, and such operations as such bodies, so compos'd, must necessarily, when there are such and such circumstances concurring, perform: thus, when we find Flies swarming, about any piece of flesh that does begin a little to ferment; Butterflies about Colworts, and several other leaves, which will serve to hatch and nourish their young; Gnats, and several other Flies about the Waters, and marishy places, or any other creatures, seeking and placing their Seeds in convenient repositories, we may, if we attentively consider and examine it, find that there are circumstances sufficient, upon the supposals of the excellent contrivance of their machine, to excite and force them to act after such or such a manner; those steams that rise from these several places may, perhaps, set several parts of these little Animals at work, even as in the contrivance of killing a Fox or Wolf with a Gun, the moving of a string, is the death of the Animal; for the Beast, by moving the flesh that is laid to entrap him, pulls the string which moves the trigger, and that lets go the Cock which on the steel strikes certain sparks of fire which kindle the powder in the pann, and that presently flies into the barrel, where the powder catching fire rarifies and drives out the bullet which kills the Animal; in all which actions, there is nothing of intention or ratiocination to be ascrib'd either to the Animal or Engine, but all to the ingeniousness of the contriver.

But to return to the more immediate consideration of our Gnat: We have in it an Instance, not usual or common, of a very strange amphibious creature, that being a creature that inhabits the Air, does yet produce a creature, that for some time lives in the water as a Fish, though afterward (which is as strange) it becomes an inhabitant of the Air, like its Sire, in the form of a Fly. And this, methinks, does prompt me to propose certain conjectures, as Queries, having not yet had sufficient opportunity and leisure to answer them my self from my own Experiments or Observations.

And the first is, Whether all those things that we suppose to be bred from corruption and putrifaction, may not be rationally suppos'd to have their origination as natural as these Gnats, who, 'tis very probable, were first dropt into this Water, in the form of Eggs. Those Seeds or Eggs must certainly be very small, which so small a creature as a Gnat yields, and therefore, we need not wonder that we find not the Eggs themselves, some of the younger of them, which I have observ'd, having not exceeded a tenth part of the bulk they have afterwards come to; and next, I have observed some of those little ones which must have been generated after the Water was inclosed in the Bottle, and therefore most probably from Eggs, whereas those creatures have been suppos'd to be bred of the corruption of the Water, there being not formerly known any probable way how they should be generated.

A second is, whether these Eggs are immediately dropt into the Water by the Gnats themselves, or, mediately, are brought down by the falling rain; for it seems not very improbable, but that those small seeds of Gnats may (being, perhaps, of so light a nature, and having so great a proportion of surface to so small a bulk of body) be ejected into the Air, and so, perhaps, carried for a good while too and fro in it, till by the drops of Rain it be wash'd out of it.

A third is, whether multitudes of those other little creatures that are found to inhabit the Water for some time, do not, at certain times, take wing and fly into the Air, others dive and hide themselves in the Earth, and so contribute to the increase both of the one and the other Element.


A good while since the writing of this Description, I was presented by Doctor Peter Ball, an ingenious Member of the Royal Society, with a little Paper of Nuts, which he told me was sent him from a Brother of his out of the Countrey, from Mamhead in Devonshire, some of them were loose, having been, as I suppose, broken off, others were still growing fast on upon the sides of a stick, which seem'd by the bark, pliableness of it, and by certain strings that grew out of it, to be some piece of the root of a Tree; they were all of them dry'd, and a little shrivell'd, others more round, of a brown colour; their shape was much like a Figg, but very much smaller, some being about the bigness of a Bay-berry, others, and the biggest, of a Hazel-Nut. Some of these that had no hole in them, I carefully opened with my Knife, and found in them a good large round white Maggot, almost as bigg as a small Pea, which seem'd shap'd like other Maggots, but shorter. I could not find them to move, though I ghess'd them to be alive, because upon pricking them with a Pinn, there would issue out a great deal of white mucous matter, which seem'd to be from a voluntary contraction of their skin; their husk or matrix consisted of three Coats, like the barks of Trees, the outermost being more rough and spongie, and the thickest, the middlemost more close, hard, white, and thin, the innermost very thin, seeming almost like the skin within an Egg's shell. The two outermost had root in the branch or stick, but the innermost had no stem or process, but was onely a skin that cover'd the cavity of the Nut. All the Nuts that had no holes eaten in them, I found to contain these Maggots, but all that had holes, I found empty, the Maggots, it seems, having eaten their way through, taken wings and flown away, as this following account (which I receiv'd in writing from the same person, as it was sent him by his Brother) manifests. In a moorish black Peaty mould, with some small veins of whitish yellow Sands, upon occasion of digging a hole two or three foot deep, at the head of a Pond or Pool, to set a Tree in, at that depth, were found, about the end of October 1663. in those very veins of Sand, those Buttons or Nuts, sticking to a little loose stick, that is, not belonging to any live Tree, and some of them also free by themselves.

Four or five of which being then open'd, some were found to contain live Insects come to perfection, most like to flying Ants, if not the same; in others, Insects, yet imperfect, having but the head and wings form'd, the rest remaining a soft white pulpy substance.

Now, as this furnishes us with one odd History more, very agreeable to what I before hinted, so I doubt not, but were men diligent observers, they might meet with multitudes of the same kind, both in the Earth and in the Water, and in the Air, on Trees, Plants, and other Vegetables, all places and things being, as it were, animarum plena. And I have often, with wonder and pleasure, in the Spring and Summer-time, look'd close to, and diligently on, common Garden mould, and in a very small parcel of it, found such multitudes and diversities of little reptiles, some in husks, others onely creepers, many wing'd, and ready for the Air; divers husks or habitations left behind empty. Now, if the Earth of our cold Climate be so fertile of animate bodies, what may we think of the fat Earth of hotter Climates? Certainly, the Sun may there, by its activity, cause as great a parcel of Earth to fly on wings in the Air, as it does of Water in steams and vapours. And what swarms must we suppose to be sent out of those plentifull inundations of water which are poured down by the sluces of Rain in such vast quantities? So that we need not much wonder at those innumerable clouds of Locusts with which Africa, and other hot countries are so pestred, since in those places are found all the convenient causes of their production, namely, genitors, or Parents, concurrent receptacles or matrixes, and a sufficient degree of natural heat and moisture.

I was going to annex a little draught of the Figure of those Nuts sent out of Devonshire, but chancing to examine Mr. Parkinson's Herbal for something else, and particularly about Galls and Oak-apples, I found among no less then 24. several kinds of excrescencies of the Oak, which I doubt not, but upon examination, will be all found to be the matrixes of so many several kinds of Insects; I having observ'd many of them my self to be so, among 24. several kinds, I say, I found one described and Figur'd directly like that which I had by me, the Scheme is there to be seen, the description, because but short, I have here adjoin'd Theatri Botanici trib. 16. Chap. 2. There groweth at the roots of old Oaks in the Spring-time, and semetimes also in the very heat of Summer, a peculiar kind of Mushrom or Excrescence, call'd Uva Quercina, swelling out of the Earth, many growing one close unto another, of the fashion of a Grape, and therefore took the name, the Oak-Grape, and is of a Purplish colour on the outside, and white within like Milk, and in the end of Summer becometh hard and woody. Whether this be the very same kind, I cannot affirm, but both the Picture and Description come very neer to that I have, but that he seems not to take notice of the hollowness or Worm, for which 'tis most observable. And therefore 'tis very likely, if men did but take notice, they might find very many differing Species of these Nuts, Ovaries, or Matrixes, and all of them to have much the same designation and office. And I have very lately found several kinds of Excrescencies on Trees and Shrubs, which having endured the Winter, upon opening them, I found most of them to contain little Worms, but dead, those things that contain'd them being wither'd and dry.


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