Part 30

This extraordinary little creature was found by my ingenious friend, Mr. John Adams, of Edmonton; he was at the New Inn, Waltham Abbey, where it was spied by some labouring men who were drinking their porter. The man who first perceived it, thought it was of an uncommon form; on a more minute inspection, it was supposed to be a louse with unusual long horns; others thought it was a mite. This produced a debate, which attracted the attention of my friend, who obtained the insect from them for further observation. Mr. Martin has given some account of it in the third volume of “The Young Gentleman and Lady’s Philosophy.” Mr. Adams favoured me with the insect, that an accurate drawing might be taken from it, which I thought would be highly pleasing not only to the lovers of microscopic observations, but also to the entomologist. It appears to be quite a distinct species from the phalangium cancroides of Linnæus, of which a good drawing has been given by Hooke, Rösel, Schæffer, &c.; it has also been described by Scopoli, Geoffroy, and other naturalists; not one, however, of these descriptions agrees with the animal under consideration. The abdomen of this is more extended, the claws are larger and much more obtuse; the body of the other being nearly orbicular, the claws slender, and finishing almost in a point, more transparent, and of a paler colour. It is very probable, that there are several species nearly similar. Mr. Marsham has two in his possession, one like the drawings of Reaumur, the other not to be distinguished from that which is represented in the plate, except that it wants the break or dent in the claws, so conspicuous in this. The latter he caught on a flower in Essex, the first week in August, firmly affixed by its claws to the thigh of a large fly, and could not disengage it from thence without considerable difficulty; to accomplish which, he was obliged to tear off the fly’s leg, and was much surprized to see the bold little creature spring forward full a quarter of an inch, and once more seize its prey, from which he again found it very difficult to disengage it. Fig. 1 represents the insect considerably magnified, Fig. 6 the natural size.[105]

[105] According to Aldrovandus, this insect was not unknown to Aristotle, who mentions it as being found in books and paper. Wolphius, on the authority of Gesner, says that a few are to be met with in some parts of Switzerland. Scaliger also notices it, having found two of them in his books. It has been by various systematic writers referred to different genera; De Geer has instituted a new genus for it under the name of chelifer; Fabricius has remanded it to that of scorpio, to which perhaps it is more nearly allied than any other.

Amongst the number of naturalists who have observed and described the insect, it appears rather extraordinary that none have met with one similar to that in the plate, in respect to the break in the claws. In a cabinet of curious microscopic objects which I purchased several years since, and which originally came from Holland, there were four of them in the most perfect condition. A botanical friend, Mr. Young, also favoured me with a living one which he found among some plants collected by him in one of his excursions; but, as his box contained a variety of plants, and he did not discover the insect till his return, it was impossible to ascertain the particular one on which it was taken. All these resembled the one here exhibited, excepting the claws being longer and more slender, and being deficient in the distinguishing characteristic; I have lately seen another, in which the two fangs that are shewn highly magnified in Plate 85 of the Naturalist’s Miscellany, are very apparent, being so large, as to exceed in diameter the thickest part of the claws.

My respectable friend, Matthew Yatman, Esq. informs me, that some years since one was found on a bottle of wine packed in saw-dust, at the house in which he then resided in Percy street; on putting the point of a pin towards it to remove it from the bottle, it ran backward, put itself into an attitude of defence, and opened its claws as meditating vengeance. In the same cellar one had many years previous been discovered, sufficiently large to admit its being fastened to a card with thread by a young gentleman, being at least four times the usual size.

Rösel says it dwells among paper, in old books and their bindings, in chests of drawers, and in the crevices of old buildings. In order to discover whether the insect possessed a sting, he often by various means endeavoured to irritate it; but it never shewed the smallest inclination to defend itself, on the contrary, it always endeavoured to avoid a contest; if so, it evidently appears that those few met with in this country are of a more bold and warlike disposition.

Seba asserts that these insects resemble the large scorpions, the tail excepted, which is small, and usually concealed by being drawn close to the under part of the abdomen; but in this respect he must probably have been mistaken, as it does not appear that this circumstance has been noticed by any other person. EDIT.

OF THE THRIPS PHYSAPUS.

Plate XVIII. Fig. 3, 4, and 5.

The insect, which is represented very considerably magnified at Fig. 3, is of the hemiptera class. It was first described and figured by De Geer in the Swedish Transactions for 1744, under the name of physapus ater, alis albis; Linnæus afterwards introduced it in a subsequent edition of the Systema Naturæ distinguished by the name thrips physapus.

These insects live upon plants, and particularly in flowers. The one figured here is the black thrips, with white wings; the antennæ have six articulations; the body is black; the wings whitish, long, and hairy; the head small, with two large reticular eyes. The antennæ are of an equal size throughout, and divided into six oval pieces which are articulated together. The extremities of the feet are furnished with a membranaceous and flexible bladder, which it can throw out and draw in at pleasure. It places and presses this bladder against the substances on which it is walking, and seems to fix itself thereby to them; the bladder sometimes appears concave towards the bottom, the concavity increasing or diminishing in proportion to the degree of pressure.

They have four wings, two upper and two under ones; these last are with great difficulty perceived, they are fixed to the upper part of the breast, lying horizontally; both of them are rather pointed towards the edges, and have a strong nerve running round them, which is set with a fringe of fibrillæ, tufted at the extremity. The wings are represented by themselves at Fig. 4; the insect of the real size at Fig. 5. They are to be found in great plenty in the spring and summer, in the flowers of the dandelion, and various other plants.

OF THE SKIN OF THE LUMP SUCKER.

Plate XVIII. Fig. 2 and 7.

For a full description of this singular fish, I must refer the reader to Pennant’s British Zoology, vol. iii. p. 117. The Linnean name is cyclopterus lumpus. Fig. 2 is a piece of the skin highly magnified: there are no scales on the body, but a great number of tubercles, which are here exhibited. Fig. 7 is the natural size of the object.

These fishes being extremely fat, renders them an agreeable diet to the natives of Greenland, in which seas they abound in the months of April and May; they also resort in multitudes during spring to the coast of Sutherland, near the Ord of Caithness in North Britain, where the seals prey greatly upon them, leaving the skins; numbers of which thus emptied float at that season ashore. When a good specimen is procured, it forms a most beautiful object for the opake microscope.

OF THE CIMEX STRIATUS.

Plate XX. Fig. 1 and A.

This is a beautiful insect of the hemiptera class, or that kind where the elytra are only in part crustaceous, and which do not form a longitudinal suture down the back, but fold over about one-third of their length toward the bottom, where it is also partly transparent. It is of the genus cimex, and called striatus by Linnæus. Its colours are bright and elegantly disposed: the head, proboscis, and thorax are black. The thorax is ornamented with yellow spots, the middle one large, and occupying almost one-third of the posterior part; the other two are on each side, and triangular. The scutellum has two yellow oblong spots, pointed at each end; the ground of the elytra is a bright yellow, spotted and striped with black. The nerves are yellow, and there is a brilliant triangular spot of orange, which unites the crustaceous and membranaceous parts; the latter is brown and clouded. The feet are of a fine red, and the rings of the abdomen are black, edged with white. This pretty insect is to be found in June, upon the elm-tree. It is represented at A of the natural size.

OF THE CHRYSOMELA ASPARAGI.

Plate XX. Fig. 2 and B.

A very common, though elegant insect of the coleoptera class, is represented at Fig. 2, as seen in the lucernal microscope, and of its natural size at B; it is called by Linnæus chrysomela asparagi, from the larva feeding on the leaves of that plant. Its shape is oblong, the antennæ black, composed of many joints nearly oval. The head is of a bright, but deep blue; the thorax red and cylindrical; the elytra blue, with a yellow margin, and three spots of the same colour on each, one at the base of an oblong form, and two united with the margin; the legs are black, but the under side of the belly is of the same blue colour with the elytra and head. This little animal, when viewed by the naked eye, scarcely appears to deserve any notice; but when examined by the microscope, is one of the most pleasing opake objects we have. It is found in June, on the asparagus after it has run to seed. De Geer says, that it is very scarce in Sweden.

OF THE MELOE MONOCEROS.

Plate XX. Fig. 3 and C.

The insect which comes at present under our inspection is particularly adapted to shew the advantages of the microscope, which alone will discover the peculiarities of its figure; this is so remarkable, that entomologists appear undetermined as to its genus. Geoffroy formed a new one for it, under the title of notoxus, in which he has been followed by Fabricius; even Linnæus himself could not determine at first where to place it, for in the Fauna Suecica he makes it an attelabus, but in the last edition of the Systema Naturæ he has fixed it as a meloe, calling it the meloe monoceros; but still he adds, “genus difficile terminatur forte huic proximum.” Both Geoffroy and Schæffer have given figures of it, but as they had not that kind of microscope which would assist them, their figures are imperfect.

The head is black, and appears to be hid or buried under the thorax, which projects forwards like a horn; the antennæ are composed of many articulations, and with the feet are of a dingy yellow. The hinder part of the thorax is reddish, the fore part black. The elytra are yellow, with a black longitudinal line down the suture; there is a band of the same colour near the apex, and also a black point near the base; the whole animal is curiously covered with hair. Geoffroy says it is found on umbelliferous plants: the one here described was found in May; the natural size is seen at C.

Plate XIX. Fig. 1 and 3,

Represent two magnified views of the feet of the monoculus apus of Linnæus. They are curiously contrived to assist the animal in swimming, and form very agreeable objects for the microscope. Fig. 2 and 4 are the same objects of the natural size.

OF THE SCALES OF FISH.

The outside covering or scales of fish afford an immense variety of beautiful objects for the microscope. They are formed in the most admirable manner, and arranged with inconceivable regularity and symmetry: some are long, others nearly round, others again square; varying in shape, not only in different species, but even considerably on the same fish; those which are taken from one part not being entirely similar to those which are taken from another.

Leeuwenhoeck supposed each scale to consist of an infinity of scales laid one over the other; or, more simply, of an infinity of strata, of which those next to the body of the fish are the largest.

These strata, when viewed with the microscope, exhibit specimens of wonderful mechanism and exquisite workmanship. In some scales we discover a prodigious number of concentric flutings, too fine, as well as too near each other, to be easily enumerated; they are probably formed by the edges of each stratum, denoting the limits thereof, and the different stages of the growth of the scale. These flutings are often traversed by others diverging from the center of the scale, and generally proceeding from thence in a straight line to the circumference.

Plate X. Fig. 7, exhibits a scale from a species of the parrot fish of the West-Indies, considerably magnified. Fig. 8, the real size of the scale.

Plate X. Fig. 9, is a magnified scale of the sea-perch, which is found on the English coast. Fig. 10, the same scale of the natural size.

Plate XIX. Fig. 7, a scale from the haddock, as seen in the microscope. Fig. 8, the same of the natural size.

Plate XIX. Fig. 9, a scale from a species of perch from the West-Indies, magnified. Fig. 10, the scale of its real size.

Plate XIX. Fig. 11, a scale from the sole-fish, delineated as it appears in the microscope; the pointed part is that which stands without the skin, as may be seen in Fig. 5, which represents a piece of the skin of a sole, as viewed by the opake microscope. Fig. 6 and 12, the same objects of their real size.

CHAP. VII.

THE NATURAL HISTORY OF THE HYDRA, OR FRESH-WATER POLYPE.

Having in the two preceding chapters given the reader such a general idea of the history and œconomy of a great variety of those minute animated bodies, called insects, as I am inclined to hope has not only afforded him entertainment and instruction, but tended to excite an emulation for further researches; I shall endeavour to gratify so laudable a disposition, by introducing him to a class of beings whose œconomy and singular properties equally engage the attention of the philosopher and the natural historian; a scene which opposes our general system of vitality, and which presents to the eye of the mind, as well as that of the body, a series of astonishing wonders. It is among the minutiæ of nature that we find her models most diversified, and displaying the marvellous fecundity of its powers.

The polypes described in this chapter are fresh-water insects, of the genus of hydra, of the order of zoophytes, and class of vermes. The body consists of a single tube, furnished at one end with long arms, by these it seizes small worms, and conveys them to its mouth. It has, according to our general notions, neither head, heart, stomach, nor intestines of any kind; and is without the distinction of sexes, yet extremely prolific. From the simplicity of its structure those of its œconomy and functions are probably derived. When they are cut or divided into a number of pieces, the separated parts in a very little time become so many perfect and distinct animals; each piece having a power of producing a head, a tail, and the other organs necessary for its existence.

They are generally known by the name of polype; but as this was thought by many to be improper, because that, strictly speaking, they have no feet, Linnæus called the genus hydra, probably from their property of re-producing the parts which are cut off, a circumstance that naturally brings to mind the fabulous story of the Lernean hydra. Dr. Hill called them biota, on account of the strong principle of life with which every part is endued.

Leeuwenhoeck, whose indefatigable industry in his researches after small insects permitted very few things to escape his notice, discovered these animals, and gave some account of them in the Philosophical Transactions for the year 1703. There is also in the same volume a letter from an anonymous hand on this subject. We had, however, no regular account of them, their various habits, their different species, or of their wonderful properties, till the year 1740, when they first engaged the attention of M. Trembley, to whose assiduity and observations we are indebted for the display of their nature and œconomy.

Previous to the successful experiments of this gentleman, Leibnitz and Boerhaave, as well as some of the ancient philosophers, reflecting on the various gradations in the scale of animated nature, had endeavoured to prove that there might be degrees of life between the animal and the plant, and that animals might be found which would propagate by slips, like plants. These conjectures were verified by Trembley, but not in consequence of any pre-conceived ideas in favour of such a supposition; on the contrary, it was only by repeated observations that he could destroy his own prejudices, and join these wonderful beings to the animal kingdom.[106]

[106] A great part of the knowledge of the ancients consisted in an extensive variety of ingenious hypotheses, the result of intense study and application; and it need not excite surprize, if, amongst a number of suppositions, some of them have since been found conformable to truth.

The moderns, animated by the example of the great Bacon, by an abundance of experiments frequently repeated, and the assistance of good instruments, have introduced unquestionable demonstration in the place of speculation; this renders the present philosophy very far superior to that of the ancients.

Thus it is with respect to the subject now under consideration; many of the ancients conjectured that animated beings might exist possessed of the wonderful properties of the hydra; that some of them, however, were even witnesses of the fact, cannot well be disputed; though it may be fairly presumed, that their knowledge of this animal, comparatively with that we are now in possession of, was very circumscribed and imperfect.

St. Augustine relates that one of his friends performed the experiment before him, of cutting a polype in two, and that immediately the two parts thus separated betook themselves to flight, moving with precipitation different ways. The original passage is too long to be here inserted, but may be found in his work “De Quantitate Animæ,” c. 62, p. 431, col. 1.

Aristotle, speaking of insects with many feet, expresses himself nearly in the same manner; without naming the particular creatures to which he alludes, he observes, that there are of these animals or insects, as well as of plants and trees, some that propagate themselves by shoots; and, as what were but the parts of a tree before, become thus distinct and separate trees; so, in cutting one of these animals, the pieces which before composed altogether but one animal, become suddenly so many distinct individuals. And he adds, that the soul in these insects is in effect but one, though multiplied in its powers, as it is in plants. Aristot. de Histor. Animal. tom. 1, lib. 4, cap. 7, pag. 824, & de Part. Animal. lib. 4, tom. 1, cap. 6, pag. 1029. &c. This will suffice to shew that the ancients were not entirely unacquainted with the subject before us; though it does not derogate from the merit of Leeuwenhoeck, Trembley, and other ingenious naturalists, by whose assiduous and patient investigations we have obtained a more perfect knowledge of this astonishing class of animated beings. EDIT.

Though natural history is so fruitful in extraordinary facts, it has hitherto produced none so singular as the various properties of the different species of the hydra.

I shall endeavour, first, to trace the progress of this discovery, in which we shall see with what sage caution and accuracy Trembley, and other naturalists examined this wonderful phænomenon, and what accumulated evidence was judged necessary to establish the fact.

We find M. Trembley writing in January, 1741, to M. Bonnet, that he did not know whether he should call the object which then engaged his attention, a plant or an animal. “I have studied it,” says he, “ever since June last, and have found in it striking characteristics of both plant and animal. It is a little aquatic being. At first sight, every one imagines it to be a plant; but if it be a plant, it is sensitive and ambulant; if it be an animal, it may be propagated by slips or cuttings, like many plants.” It was not till the month of March, in the same year, that he could satisfy himself as to their nature.

When Reaumur saw, for the first time, two polypes formed from one that he had divided into two parts, he could hardly believe his eyes; and even after having repeated the operation an hundred times, and again examined it an hundred more, he says that the sight was not become familiar to him.

The first account the Royal Society received of the surprizing properties of the hydra, was in a letter from M. Buffon, dated the 18th of July, 1741, to Martin Folkes, Esq. their president, acquainting them with the discovery of a small insect called a polypus, which is found sticking about the common duck weed, and which, being cut in two, puts forth from the upper part a tail, and from the lower end a head, so as to become two animals instead of one. If it be cut into three parts, the middlemost puts out from one end a head, and from the other a tail, so as to become three distinct animals, all living like the first, and performing the various offices of their species: which observations are, adds Buffon, well averred.

There is no phænomenon in all natural history more astonishing than this, that man, at pleasure, should have a kind of creative power, and out of one life make two, each completely formed with all its apparatus and functions, its perceptions and powers of motion and self-preservation; and as complete in all respects as that from which they derived their existence, and equally enjoying the humble gratifications of their nature.[107]

[107] Goldsmith’s History of the Earth and Animated Nature.

Mr. Folkes, in confirmation of the foregoing article, communicated to the Society a letter from the Hon. W. Bentinck, Esq. at the Hague, dated September, describing the insects discovered by Trembley, adding, that he himself had seen them. In November, a letter was read from Dr. Gronovius, of Leyden, giving an account of a water insect not yet known to, or described by any author; after describing it, he adds, “but what is more surprizing, if this animal is cut into five or six pieces, in a few hours there will be as many animals, exactly similar to their parent.” The accounts of this animal were so extraordinary, that they were not credited until Professors Albinus and Musschenbroeck were provided with some specimens, and found all that had been related thereof to be exactly true.