The same train of reasoning may be applied to microscopic insects and animalcula; we see them move, but because the muscles and members which occasion these motions are invisible, shall we infer that they have not muscles, with organs appropriated to the motion of the whole and its parts? To say that they exist not, because we cannot perceive them, would surely not be a rational conclusion. Our senses are indeed given us, that we may comprehend some effects; but then we have also a mind with reason bestowed upon us, that from the things which we do perceive with our senses, we may deduce the nature of those causes and effects which are imperceptible to the corporeal eye.
Messrs. Buffon, Needham, and Baron Münchhausen, have considered this part of animated nature in so different a light from other writers, that we cannot with propriety entirely pass them over. Needham imagined that there was a vegetative force in every microscopical point of water, and every visible filament of which the whole vegetable contexture consists; that the several species of microscopic animals may subside, resolve again into gelatinous filaments, and again give lesser animals, and so on, till they can be no further pursued by glasses. That agreeable to this idea, every animal or vegetable substance advances as fast as it can in its revolution, to return by a slow descent to one common principle, whence its atoms may return again, and ascend to a new life. That notwithstanding this, the specific seed of one animal can never give another of a different species, on account of the preparation it must receive to constitute it this specific seed.
Buffon asserts, that what have been called spermatic animals, are not creatures really possessing life, but something proper to compose a living creature, distinguishing them by the name of organic particles, and that the moving bodies which are to be found in the infusions either of animal or vegetable substances, are of the same nature.
Baron Münchhausen supposed that the seeds of mushrooms were first animals, and then vegetables; and this, because he had observed some of the globules in the infusions of mushrooms, after moving some time, to begin to vegetate.
It might be sufficient in the first instance to observe, that Messrs. Needham, and Buffon, by having recourse to a vegetative force and organic particles, to account for the existence and explain the nature of animalcula, and the difficulties of generation,have substituted words in the place of things; and that we are no gainers by the substitution, unless they explain the nature of these powers. But to this we may add, that all those who have examined the subject with accuracy and attention, as Bonnet, De Saussure, Baker, Wrisberg, Spalanzani, Haller, Ellis, Müller, Ledermüller, Corti, Rofredi, &c. disagree with the foregoing gentlemen, proving that they had deceived themselves by inaccurate experiments, and that one of them, Buffon, had not seen the spermatic animals he supposed himself to be describing, insomuch that Needham was at last induced to give up his favourite hypothesis.
Though we can by no means pretend to account for the appearance of most animalcula, yet we cannot help observing, that our ignorance of the cause of any phænomenon is no argument against its existence. Though we are not, for instance, able to account in a satisfactory manner for the origin of the native Americans, yet we suppose Buffon himself would reckon it absurd to maintain, that the Spaniards on their arrival there found onlyORGANIC PARTICLESmoving about in disorder. The case is the very same with the eels in paste, to whose animation he objects. They are exceedingly small in comparison with us; but, with the solar microscope, Baker has made them assume a more respectable appearance, so as to have a diameter of an inch and an half, and a proportionable length. They swam up and down very briskly; the motion of their intestines was very visible; when the water dried up they died with apparent agonies, and their mouths opened very wide. Now, were we to find a creature of the size of this magnified eel gasping in a place where water had lately been, we certainly should never conclude it to be merely anORGANIC PARTICLE, or fortuitous assemblage of them, but a fish. Why then should we conclude otherwise with regard to the eel in its natural state, than that it is a little fish? In reasoning onthis subject, we ought ever to remember, that however essential the distinction of bodies into great and small may appear to us, they are not so to the Deity, with whom, as Baker well expresses himself, “an atom is a world, and a world but as an atom.” Were the Deity to exert his power a little, and give a natural philosopher a view of a quantity of paste filled with eels, from each of whose bodies the light was reflected as in the solar microscope; our philosopher, instead of imagining them to be mere organic particles, as the paste would appear like a little mountain, he would probably look upon the whole as an assemblage of serpents, and be afraid to come near them. Whenever, therefore, we discover beings to appearance endued with a principle of self-preservation, or whatever we make the characteristic of animals, neither the smallness of their size, nor the impossibility of our knowing how they came there, ought to cause us to doubt of their being animated.
I shall here insert some extracts of the experiments made by Ellis at the desire of Linnæus, and which are a full refutation of those made by Needham and Münchhausen. By those he made on the infusions of mushrooms in water, it appeared evidently that the seeds were put in motion by minute animals, which arose on the decomposition of the mushroom; these, by pecking at the seeds, which are little round reddish bodies, moved them about with great agility in a variety of directions, while the little animals themselves were scarce visible till the food they had eaten discovered them.
The ramified filaments, and jointed or coralloid bodies, which the microscope discovers to us on the surface of most vegetable and animal infusions, when they become putrid, and which were supposed by Needham to be zoophytes, were found by Ellis to be of that genus of fungi called mucor, many of which have beenfigured by Michelius, and described by Linnæus. Their vegetation is so quick, that they may be seen to grow and seed under the eye of the observer. Other instances of similar mistakes in Needham’s experiments may be seen in Ellis’s paper, Philos. Trans. vol. lix. p. 138.
A species of mucor arises also from the bodies of insects putrefying in water; this species sends forth a mass of transparent filamentous roots, from whence arise hollow seed vessels; on the top there is a hole, from which minute globules often issue in abundance, and with considerable elastic force, which move about in the water. It will however be found, with a little attention, that the water is full of very minute animalcula, which attack these seeds, and thus prolong their motion; but after a small space of time they rise to the surface, and remain there without any motion; a fresh quantity rises up, and floating to the edge of the water, remains there inactive; but no appearance can be observed of detached and separated parts becoming what are called microscopic animalcula. Indeed, it is surprizing that Needham should ever take the filaments of the moistened grains for any thing else than a vegetable production, a true species of mouldiness.
On the 25th of May, Fahrenheit’s thermometer 70°, Ellis boiled a potatoe in the New River water, till it was reduced to a mealy consistence. He put part of it, with an equal proportion of the boiling liquor, into a cylindrical glass vessel, that held something less than half a wine pint, and covered it close immediately with a glass cover. At the same time he sliced an unboiled potatoe, and, as near as he could judge, put the same quantity into a glass vessel of the same kind, with the same proportion of New River water not boiled, and covering it with a glass cover, placed both vessels close to each other. On the26th of May, twenty-four hours afterwards, he examined a small drop of each by the first magnifier of Wilson’s microscope, whose focal distance is reckoned at1⁄50part of an inch; and, to his amazement, they were both full of animalcula of a linear shape, very distinguishable, moving to and fro with great celerity; so that there appeared to be more particles of animal than vegetable life in each drop. This experiment he repeatedly tried, and always found it to succeed in proportion to the heat of the circumambient air; so that even in winter, if the liquors be kept properly warm, at least in two or three days the experiment will succeed.
The animalcula are infinitely smaller than spermatic animals, and of a very different shape; the truth of which every accurate observer will soon be convinced of, whose curiosity may lead him to compare them, and he is persuaded they will find they are no way akin. Having learnt from M. De Saussure, of Geneva, that he found one kind of these animalcula infusoria that increases by dividing across into nearly two equal parts, and that the infusion was made from hemp-seed, he procured a quantity of this seed, some of it he put into New River water, some into distilled water, and some into very hard pump water; the result was, that in proportion to the heat of the weather, or the warmth in which they were kept, there was an appearance of millions of minute animalcula in all the infusions; and some time after some oval ones made their appearance; these were much larger than the first, which still continued. These wriggled to and fro in an undulatory motion, turning themselves round very quick all the time that they moved forwards.
Ellis found out by mere accident a method to make their fins appear very distinctly, especially in the larger kind of animalcula, which are common to most vegetable infusions, such as the terebella.This has a longish body, with a cavity or groove at one end, like a gimblet. By applying a small stalk of the horseshoe geranium, the geranium zonale of Linnæus, fresh broken, to a drop of water in which these animalcula are swimming, we shall find that they will become instantly torpid, contracting themselves into an oblong oval shape, with their fins extended like so many bristles all round their bodies. The fins are in length about half the diameter of the middle of their bodies. After lying in this state of torpitude for two or three minutes, if a drop of clean water be applied to them, they will recover their shape, and swim about immediately, rendering their fins again invisible. Before he discovered this expedient, he tried to kill them by different kinds of salts and spirits; but though they were destroyed by these means, their fins were so contracted, that he could not distinguish them in the least.[118]
[118]The preceding recital of the hypothesis of Messrs. Buffon, Needham, and Baron Münchhausen, may appear superfluous, having been so ably refuted by Mr. Ellis; the consideration, however, that it may afford entertainment to some of my readers, and prove beneficial to others, by cautioning them against too precipitately adopting plausible suppositions, induced me to retain the account.Edit.
[118]The preceding recital of the hypothesis of Messrs. Buffon, Needham, and Baron Münchhausen, may appear superfluous, having been so ably refuted by Mr. Ellis; the consideration, however, that it may afford entertainment to some of my readers, and prove beneficial to others, by cautioning them against too precipitately adopting plausible suppositions, induced me to retain the account.Edit.
It is one of the wonders of the modern philosophy to have invented means for bringing creatures so imperceptible as the various animalcula under our cognizance and inspection. One might well have deemed an object that was a thousand times too little to be able to affect our sense, as perfectly removed from human discovery; yet we have extended our sight over animals to whom these would be mountains. The naked eye takes in animal beings from the elephant to the mite; but below this, commences a new order, reserved only for the microscope, which comprehends all those from the mite, to those many millions of times smaller; and this order cannot be said to be exhausted, if the microscope be not arrived at its ultimate state of perfection.In reality, the greater number of microscopic animalcula are of so small a magnitude, that through a lens, whose focal distance is the tenth part of an inch, they only appear as so many points; that is, their parts cannot be distinguished, so that they appear from the vertex of that lens under an angle not exceeding the minute of a degree. If we investigate the magnitude of such an object, it will be found nearly equal to3⁄100000of an inch long. Supposing, therefore, these animalcula to be of a cubic figure, that is, of the same length, breadth, and thickness, their magnitude would be expressed by the cube of the fraction3⁄100000, that is, by the number27⁄1000000000000000, that is, each animalculum is equal to so many parts of a square inch. This contemplation of animalcula has rendered the idea of indefinitely small bodies very familiar to us; a mite was formerly thought the limit of littleness, but we are not now surprized to be told of animals many millions of times smaller than a mite; for, “there are in some liquors animalcules so small, as, upon calculation, the whole magnitude of the earth is not found large enough to be a third proportional to these minute floating animals and the whales in the ocean.”[119]These considerations are still further heightened, by reflecting on the internal structure of animalcula, for each must have all the proportion, symmetry and adjustment of that organized texture, which is indispensably necessary for the several functions of life, and each must be furnished with proper organs, tubes, &c. for secreting the fluids, digesting its food, and propagating its species.[120]
[119]Chambers’s Cyclopedia by Rees, Art. Animalcule.[120]Minute animals proportionably exceed the larger kinds in strength, activity, and vivacity. It has been already observed,p. 212, that the spring of a flea vastly outstrips any thing animals of a greater magnitude are capable of; the motion of a mite is much quicker than that of the swiftest race-horse. M. De L’Isle, Hist. Acad. Scienc. 1711. p. 23, has given the computation of the velocity of a little creature, so small as to be scarcely visible, which he found to run three inches in a second; supposing now its feet to be the fifteenth part of a line, it must make five-hundred steps in the space of three inches, that is, it must shift its legs five-hundred times in a second, or in the time of the ordinary pulsation of an artery. The rapidity with which many of the water insects skim the surface of the fluid, and others swim in it, is astonishing, nor is the celerity of the various species of animalcula infusoria less deserving of admiration.Edit.
[119]Chambers’s Cyclopedia by Rees, Art. Animalcule.
[120]Minute animals proportionably exceed the larger kinds in strength, activity, and vivacity. It has been already observed,p. 212, that the spring of a flea vastly outstrips any thing animals of a greater magnitude are capable of; the motion of a mite is much quicker than that of the swiftest race-horse. M. De L’Isle, Hist. Acad. Scienc. 1711. p. 23, has given the computation of the velocity of a little creature, so small as to be scarcely visible, which he found to run three inches in a second; supposing now its feet to be the fifteenth part of a line, it must make five-hundred steps in the space of three inches, that is, it must shift its legs five-hundred times in a second, or in the time of the ordinary pulsation of an artery. The rapidity with which many of the water insects skim the surface of the fluid, and others swim in it, is astonishing, nor is the celerity of the various species of animalcula infusoria less deserving of admiration.Edit.
Having thus given a general idea of the properties of animalcula, I now proceed to describe the various individuals, following the arrangements of O. F. Müller,[121]and giving the discriminating characters by which he has distinguished them; abridging, enlarging, or altering the descriptions, to render them in some instances more exact, in others less tedious, and upon the whole, I hope, more interesting to the reader.
[121]Müller Animalcula Infusoria, Fluviatilia, et Marina.
[121]Müller Animalcula Infusoria, Fluviatilia, et Marina.
I.THOSE THAT HAVE NO EXTERNAL ORGANS.1.Monas: punctiforme. A mere point.2.Proteus: mutabile. Mutable, or changeable.3.Volvox: sphæricum. Spherical.4.Enchelis: cylindraceum. Cylindrical.5.Vibrio: elongatum. Long.Membranaceous.6.Cyclidium: ovale. Oval.7.Paramæcium: oblongum. Oblong.8.Kolpoda: sinuatum. Crooked, or bent.9.Gonium: angulatum. With angles.10.Bursaria. Hollow like a purse.II.THOSE THAT HAVE EXTERNAL ORGANS.Naked, or not inclosed in a shell.11.Cercaria: caudatum. With a tail.12.Leucophra: ciliatum undique. Every part ciliated.13.Trichoda: crinitum. Hairy.14.Kerona: corniculatum. With horns.15.Himantopus: cirratum. Cirrated, or curled.16.Vorticella: ciliatum apice. The apex ciliated.Covered with a shell.17.Brachionus: ciliatum apice. The apex ciliated.
I.THOSE THAT HAVE NO EXTERNAL ORGANS.
1.Monas: punctiforme. A mere point.
2.Proteus: mutabile. Mutable, or changeable.
3.Volvox: sphæricum. Spherical.
4.Enchelis: cylindraceum. Cylindrical.
5.Vibrio: elongatum. Long.
Membranaceous.
6.Cyclidium: ovale. Oval.
7.Paramæcium: oblongum. Oblong.
8.Kolpoda: sinuatum. Crooked, or bent.
9.Gonium: angulatum. With angles.
10.Bursaria. Hollow like a purse.
II.THOSE THAT HAVE EXTERNAL ORGANS.
Naked, or not inclosed in a shell.
11.Cercaria: caudatum. With a tail.
12.Leucophra: ciliatum undique. Every part ciliated.
13.Trichoda: crinitum. Hairy.
14.Kerona: corniculatum. With horns.
15.Himantopus: cirratum. Cirrated, or curled.
16.Vorticella: ciliatum apice. The apex ciliated.
Covered with a shell.
17.Brachionus: ciliatum apice. The apex ciliated.
Vermis inconspicuus, simplissimus, pellucidus, punctiformis. An invisible,[122]pellucid, simple, punctiform worm.
[122]By invisible, we only mean that they are too small to be discerned by the naked eye.
[122]By invisible, we only mean that they are too small to be discerned by the naked eye.
M. gelatinosa. Gelatinous mona.
Animalcules semblable a des points. Spallanzani Opusc. Phys. I. Bullæ continuo motu. Bonanni Obs. p. 174.
Among the various animalcula which are discovered by the microscope, this is the most minute, and the most simple; a small jelly-like point, eluding the powers of the compound microscope, and being but imperfectly seen by the single; these, and some others of the mona kind, are so delicate and slender, that it is no wonder they often escape the sight of many who have examined infusions with attention; in a full light they totally disappear, their thin and transparent forms blending as it were with the water in which they swim.
Small drops of infused water are often so full of these, that it is not easy to discover the least empty space, so that the water itself appears changed into another substance less transparent, but consisting of innumerable globular points, thick sown together; which, though full of life, seem only a kind of inflated bladders. In this a motion may be perceived, something similar to that which is observed when the sun’s rays shine on the water, the animalcula being violently agitated, or in a commotion like unto a hive of bees. They are very common in ditch water, and in almost all infusions, both of animal and vegetable substances.
M. albida puncto, variabili instructa,Plate XXV.Fig. 1. White mona, with a variable point.
This animalculum appears as a white point, which, when it is highly magnified, is somewhat of an egg-shape; the smaller end is generally marked with a black point; the situation of this is sometimes varied, and found at the other end of the animalculum: sometimes two black points are to be seen crossing the middle of the body. It was found in sea water that had been kept the whole winter; it was not, however, very fetid; there were no other animalcula in the same water.
M. nigra. A black mona.
A very minute point, solid, opake and black, round and long. They are dispersed in the infusion, and move with a slow wavering motion; were found in a fetid infusion of pears.
M. hyalina puncto centrali notata. Transparent like talc, with a point in the middle.
The margin black, and a black point in the middle; it movesirregularly, is found in ditches covered with conferva, and frequently with the cyclidium milium, seeNo. 84.
M. hyalina. Transparent mona of the appearance of talc.
This is among the number of the smaller animalcula, nearly of a round figure, and so pellucid, that it is not possible to discover the least vestige of intestines. Though they may often be seen separate, yet they are more generally collected together, forming a kind of vesicular or membranaceous mass. Contrary to the custom of other animalcula, they seek the edges of the evaporating water, the consequence of which is almost immediate death. When the water is nearly evaporated, a few dark shades are perceived, probably occasioned by the wrinkling of the body. A slow tremulous motion, confined to one spot, may be perceived at intervals; this in a little time becomes more lively, and soon pervades the whole drop. Its motions are in general very quick: two united together may sometimes be seen swimming among the rest; while in this situation, they have been mistaken by some writers for a different species, whereas it is the same generating another by division. It is to be found in all water, though but seldom in that which is pure; they are in great plenty in the summer in ditch water, also in infusions of animal or vegetable substances, made either of fresh or salt water, myriads being contained in a drop; numbers of various sizes are to be found in the filth of the teeth.[123]
[123]The circumstance of animalcula being found in the teeth is mentioned with confidence by various authors; some doubts may, however, still remain of the fact. Mr. Willughby detected a woman, who pretended to take worms out of the teeth with a quill, having forced the quill, from her just as she was putting it into his mouth, and found small worms in it; see Birch’s History of the Royal Society, vol. iv. p. 387. I am inclined to think that the accounts usually met with in authors have no better foundation. It has also repeatedly happened, that ingenious men, from their anxiety for discovery, have imagined that objects have appeared to their view, which, having related as facts, themselves or others have afterwards found to be nothing more than a deceptio visus; and thus they have been, at least for a time, the unintentional promulgators of error; considerable caution is therefore necessary on these occasions, seep. 132,133.Some authors, in support of a favourite system, have made bold assertions on the subject of animalcula; the small-pox, the measles, the epilepsy, &c. have been attributed to them: Langius reduces all diseases in general to the same principle. A writer at Paris, who assumed the title of an English physician, has proceeded still farther; he not only accounts for all diseases, but for the operation of all medicines, from the hypothesis of animalcula. He has peculiar animals for every disorder; scorbutic animalcula, podagrical animalcula, variolous animalcula, &c. all at his service. Journ. des Scav. tom. lxxxvii. p. 535, &c.It is not at all surprising that the wonderful discoveries relating to animalcula should have been applied, however improperly, to support the most whimsical and chymerical systems. Most of the discoveries in natural philosophy have been subjected to similar abuses, and laid the foundation for the warm imaginations of some men to fabricate visionary theories; these have been of great prejudice to real science, the primary object and ultimate reward of which is the acquisition of truth.Edit.
[123]The circumstance of animalcula being found in the teeth is mentioned with confidence by various authors; some doubts may, however, still remain of the fact. Mr. Willughby detected a woman, who pretended to take worms out of the teeth with a quill, having forced the quill, from her just as she was putting it into his mouth, and found small worms in it; see Birch’s History of the Royal Society, vol. iv. p. 387. I am inclined to think that the accounts usually met with in authors have no better foundation. It has also repeatedly happened, that ingenious men, from their anxiety for discovery, have imagined that objects have appeared to their view, which, having related as facts, themselves or others have afterwards found to be nothing more than a deceptio visus; and thus they have been, at least for a time, the unintentional promulgators of error; considerable caution is therefore necessary on these occasions, seep. 132,133.
Some authors, in support of a favourite system, have made bold assertions on the subject of animalcula; the small-pox, the measles, the epilepsy, &c. have been attributed to them: Langius reduces all diseases in general to the same principle. A writer at Paris, who assumed the title of an English physician, has proceeded still farther; he not only accounts for all diseases, but for the operation of all medicines, from the hypothesis of animalcula. He has peculiar animals for every disorder; scorbutic animalcula, podagrical animalcula, variolous animalcula, &c. all at his service. Journ. des Scav. tom. lxxxvii. p. 535, &c.
It is not at all surprising that the wonderful discoveries relating to animalcula should have been applied, however improperly, to support the most whimsical and chymerical systems. Most of the discoveries in natural philosophy have been subjected to similar abuses, and laid the foundation for the warm imaginations of some men to fabricate visionary theories; these have been of great prejudice to real science, the primary object and ultimate reward of which is the acquisition of truth.Edit.
The animalcula of this, and the first species are so numerous as to exceed all calculation, though they are contained in a very confined space.
M. circulo notata. Mona, marked with a circle.
This lucid little point may be discovered with the third lens of the common single microscope; when the magnifying power is increased, it appears either of an oval or spherical figure, for it assumes each of these at pleasure. It is transparent, and has a small ellipse inscribed as it were within its circumference; this ellipse is moveable, being sometimes in the middle, sometimes a little towards the fore-part, at others, nearer the hind-part. There is a considerable variety in its motions; it often turns round for a long time in the same place; an appearance like two kidneys may sometimes be perceived in the middle of the body, and the animalculum is beautifully encompassed with a kind of halo, arising most probably from invisible and vibrating fibrillæ. They are to be found in the purest waters.
M. ovata, hyalina, margine nigro. Egg-shaped, transparent mona, with a black margin.
These animated points seem to be nearly fixed to one spot, where they have a fluctuating or reeling motion. They are frequently surrounded with a halo, and differ in their figure, being sometimes rather spherical, at others quadrangular. The black margin is not always to be found, and sometimes one would almost be tempted to think it had a tail. They are found in urine which has been kept for a time. The urine is covered, after it has remained in the vessel, with a dark-coloured pellicle or film, in which these animals live: although the urine was preserved for several months, no new animalcula were observed therein. It has been already shewn, that a drop of urine is in general fatal to other animalcula, yet we find in this instance, that there are animated beings of a peculiar kind, appropriated to, and living in it.
M. hyalina compressa. Flat transparent mona.
This is mostly found in salt water. It is of a whitish colour, more than twice as long as it is broad, transparent, with a dark margin, the motion vacillatory; it often appears as if double.
M. hyalina, margini virente. Transparent mona, with a green margin.
Little spherical pellucid grains of different sizes, the circumference green, a green bent line passes through the middle of some, probably indicating that they are near separating or dividing into two distinct animalcula; sometimes three or four, at others, six, seven, or even more, are collected together. They rove about with a wavering motion; and are mostly found in the month of March in marshy grounds.
M. hyalina gregaria. Transparent gregarious mona.
It is not easy to decide on the nature of these little assemblages of corpuscles, which sometimes consist of four, at others of five, and frequently of many more: the corpuscles are of different sizes, according to the number assembled in one group. When collected in a heap, the only motion they have is a kind of revolution or rotatory one. The smaller particles separate from the larger, often dividing into as many portions as there are constituent particles in the group; when separated, they revolve with incredible swiftness. To try whether this was a group of animalcula collected together by chance, or whether this was their natural state, the following experiment was made. A single corpuscle was taken the moment it was separated from the heap, and placed in a glass by itself; it soon increased in size, and when it had attained nearly the same bulk as the group from which it was separated, the surface began to assume a wrinkled appearance, which gradually changed till it became exactly similar to the parent group. This new-formed group was again decomposed, like the preceding one, and in a little time the separated particles became as large as that from which they proceeded. It is found in a variety of infusions.
Vermis inconspicuus, simplicissimus, pellucidus, mutabilis. An invisible, very simple, pellucid worm, of a variable form.
P. in ramulos diffluens,Plate XXV.Fig. 2 and 3. Proteus, branching itself out in a variety of directions.
A very singular animalculum, appearing only as a grey mucous mass; it is filled with a number of black globules of different sizes, and is continually changing its figure. Being formed of a gelatinous pellucid substance, the shape is easily altered, and it pushes out branches of different lengths and breadths. The globules which are within divide and pass immediately into the new formed parts, always following the various changes of form in the animalcula. The changes that are observed in the form of this little creature, do not arise from any extraneous cause, but are entirely dependent on its internal powers. It is to be met with but very seldom; the indefatigable Müller only saw it twice, although he examined such an immense variety of infusions. It is to be found in fenny situations.
P. in spiculum diffluens,Plate XXV.Fig. 4 and 5. Proteus, running out into a fine point.
A gelatinous pellucid body, stored with black molecules; it changes its form like the preceding, but always in a regular order, first extending itself out in a straight line, Fig. 5, the lower part terminating in an acute bright point, a, without any intestines; and the globules being all collected in the upper part, c,it next draws the pointed end up towards the middle of the body, swelling it into a round form. The contraction goes on for some time, after which the lower part is swelled out as it is represented in Fig. 4, d; the point a, is afterwards projected from this ventricose part. It passes through five different forms before it arrives at that which is seen, at Fig. 4. It scarcely moves from one spot, only bending about sideways. It is to be found in river water.
Volvox inconspicuus, simplicissimus, pellucidus, sphæricus. An invisible, very simple, pellucid, spherical worm.
V. sphæricus, nigricans, puncto lucido. Spherical, of a black colour, with a lucid point.
A small globule; one hemisphere is opake and black, the other has a pellucid crystalline appearance; a vehement motion is observable in the dark part. It moves in a tremulous manner, and often passes through the drop, turning round as if upon an axis. Many may be often seen joined together in their passage through, the water; they sometimes move as in a little whirlpool, and then separate. They are found in great numbers on the surface of fetid sea water.
V. sphæricus, viridis, peripheria hyalina. Spherical and green, the circumference of a bright colour.
There seems to be a kind of green opake nucleus in this animalculum; the circumference is transparent. It is to be foundgenerally in the month of June, in marshy places; it moves but slowly.
V. globosus; postice subobscurus. Globular volvox, the hind-part somewhat obscure.
This globular animalculum is ten times larger than the monas lens; it verges sometimes a little towards the oval in its form. The intestines are just visible, and make the hinder part of the body appear opake; it has commonly a slow fluttering kind of motion, but if it be disturbed, the motion is more rapid. It is found in most infusions of vegetables.
V. sphæricus, interaneis immobilibus virescentibus. Small round volvox, with immoveable green intestines.
This is a small transparent animalculum; its intestines are immoveable, of a green colour, and are placed near the middle of the body, the edges often yellow; a small obtuse incision may be discovered on the edge, which is, perhaps the mouth of the animalculum. This little creature appears to be encompassed with a kind of halo or circle. If this be occasioned by the vibratory motion of any fringe of hairs, they are invisible to the eye, even when assisted by the microscope. It seems to have a kind of rotatory motion, at one time slow, at another quick; and is to be found in water where the lemna minor, or least ducks-meat, grows, sometimes as late as the month of December.
V. sphæricus, opacus, interaneis immobilibus. Spherical and opake, with immoveable intestines.
This is much smaller than the preceding, and is marked with several circular lines; no motion is to be perceived among the interior molecules. It sometimes moves about in a straight line, sometimes its course is irregular, at others it keeps in the same spot with a tremulous motion.
V. sphæricus, moleculis crystallinis, æqualibus distantibus. Spherical volvox, with crystalline molecules, placed at equal distances from one another.
When very much magnified this animalculum seems to have some relation to the vorticella socialis, as seen with the naked eye. It consists of crystalline molecules, disposed in a sphere, and filling up the whole circumference; they are all of an equal size. Whether they are included in a common membrane, or whether they are united by one common stalk, as in the vorticella socialis, has not been discovered. We are also ignorant of the exact figure of the little particles of which it is composed; when a very large magnifying power is used, some black points may be discerned in the center of the crystalline molecules. The motion is sometimes rotatory, sometimes from right to left, and the contrary. It is found where the chara vulgaris has been kept.
V. sphæricus, moleculis similaribus rotundis.Pl. XXV.Fig. 6. Spherical volvox, with round molecules.
This spherule is formed of pellucid homogeneous points of different sizes. It moves slowly about a quarter of a circle from right to left, and then back again from left to right.
V. hemisphæricus, moleculis similaribus lunatis.Plate XXV.Fig. 7. An hemispherical volvox, with lunular molecules.
Is a small roundish transparent body, composed of innumerable molecules, homogeneous, pellucid, and of the shape of the moon in its first quarter, without any common margin. It is in a continual two-fold motion; the one, of the whole mass turning slowly round; the other, of the molecules one among the other. They are found in marshy places in the beginning of spring.
V. sphæricus membranaceus. Spherical membranaceous volvox.
This is a transparent globule, of a greenish colour; the fœtus is composed of smaller greenish globules. It becomes whiter and brighter with age, moves slowly round its axis, and may be perceived by the naked eye. But to the microscope the superficies of this pellucid membrane appears covered with molecules, as if it were granulated, which has occasioned some observers to imagine it to be hairy; the round pellucid molecules that are fixed in the center are generally largest in those that are young. The exterior molecules may be wiped off, leaving the membrane naked. When the young ones are of a proper size, the membrane opens, and they pass through the fissure; after this the mother melts away. They sometimes change their spherical figure, the superficies being flattened in different places. Most authors speak of finding eight lesser globules within the larger; but Müller says, that he has counted thirty or forty of different sizes. This wonderful capsulate situation of its progeny is well known; indeed it often exhibits itself big with children and grand-children.
Leeuwenhoeck was the first who noticed this curious animalculum, and depicted it; a circumstance which has not been mentioned by Baker and other microscopic writers, who have described it. It may be found in great plenty in stagnant watersin spring and summer, and in infusions of hemp-seed and tremella. Baker describes it as follows: This singular minute water animal, seen before the microscope, appears to be exactly globular, without either head, tail, or fins. It moves in all directions, forwards or backwards, up or down, rolling over and over like a bowl, spinning horizontally like a top, or gliding along smoothly without turning itself at all. Sometimes its motions are very slow, at other times very swift; and when it pleases, it can turn round as upon an axis very nimbly, without moving out of its place. The body is transparent, except where the circular spots are placed, which are probably its young. The surface of the body in some is as it were dotted all over with little points, and in others, as if granulated like shagreen. Baker thought also that in general it appeared as if it was set round with short moveable hairs. By another writer they are thus described: These animalcula are at first very small, but grow so large as to be discerned with the naked eye; they are of a yellowish green colour, globular figure, and in substance membranaceous and transparent. In the midst of this substance several small globes may be perceived; each of these are smaller animalcula, which have also their diaphanous membrane, and contain within themselves still smaller generations, which may be distinguished by the assistance of very powerful glasses. The larger globules may be seen to escape from the parent, and then increase in size, as has been already observed.
V. membranaceus orbicularis, centro moleculis sphæricis viridibus. Membranaceous orbicular, with spherical green molecules in the center.
This animalculum has some resemblance to the volvox uva, but is sufficiently distinguished by the surrounding bright orbicular membrane: the middle part is full of clear green globules. Theglobules seldom move, though a quivering motion may sometimes be perceived at the center. It has a slow rotatory motion, and is found amongst the lemna, in the months of October and December.
V. globosus, moleculis sphæricis virescentibus nudis. Globular volvox, composed of green spherical globules, which are not inclosed in a common membrane.
This animalculum seems to be a kind of medium between the volvox pilula,No. 16, and the gonium pectorale,No. 114, being, like the one, composed of green spherules, and in form, resembling the other. It consists of a congeries of equal globules of a greenish colour, with a bright spot in the middle; the whole mass is sometimes of a spherical form, sometimes oval, without any common membrane; a kind of halo may be perceived round it, but whether this is occasioned by the motion of any invisible hairs has not been discovered. The mass generally moves from right to left, and from left to right; scarce any motion can be discovered in the globules themselves. It was found in the month of August, in water where the lemna polyrrhiza was growing. Two masses of these globules have been seen joined together. They contain from four to fifty of the globules, of which a solitary one may now and then be found.
V. ramulis simplicibus et dichitomis, rosula globulari terminatis. A volvox with simple dichitomous branches, terminating in a little bunch of globules.
It consists of a number of floccose opake branches, which are invisible to the naked eye; at the apex of these there is a little congeries of very minute oval pellucid corpuscles. Müller at first thought it to be a species of microscopic and river sertularia; butafterwards he found the bunches quitting the branches, and swimming about in the water with a proper spontaneous motion. Many old branches were found deserted of their globules, while the younger branches were furnished with them. It was found in river water in November 1779 and 1780.
Vermis inconspicuus, simplicissimus, cylindraceus. An invisible, simple, cylindric worm.
E. subcylindrica, antice oblique truncata. Green enchelis, of a subcylindric figure, the fore-part truncated.
This is an opake green, subcylindric animalculum, with an obtuse tail, the fore-part terminating in an acute truncated angle; the intestines obscure and indistinct. It is continually varying in its motion, turning from right to left.
E. viridis, subcylindracea, antice obtusa, postice acuminata,Plate XXV.Fig. 8. Green enchelis, subcylindric, the fore-part obtuse, the hinder part pointed.
It is an opake animalculum, of a green colour; there is a small pellucid spot in the fore-parta, in which two black points may be seen; a kind of double band,c c, crosses the middle of the body. The hinder part is pellucid and pointed; an incision is discovered at the apex of the fore-part, which seems to be the mouth. When in motion, the whole of it appears opake and green. It is found in marshes.
E. viridis, cylindrica, subacuminata gelatinosa. Green, cylindrical, gelatinous, the end somewhat pointed.
The body is round, the colour a very dark green, so that it is quite opake; the fore-part is bluntly rounded off, the hinder-part is somewhat tapering, but finishes with a rounded end. From its opacity, no internal parts can be discovered; there is a degree of transparency near the ends. It is exceeding idle, moving very slowly; to be found, though rarely, in an infusion of lemnæ.
E. obovato opaca, interaneis mobilibus. Enchelis, of an egg-shape, opake with moveable intestines.
It is an opake body, with a pellucid margin; both extremities are obtuse, but the upper one much more so than the under one; it is filled with moveable spherules. Its motion is generally quick, either to the right or the left; it is probably furnished with hairs, because, when moving rapidly, the margin appears striated. It is found in water that has been kept for months.
E. ovato cylindracea, interaneis immobilibus. Enchelis partly oval, partly cylindrical, the interior parts immoveable.
An oval animalculum, round the fore-part smaller than the hind-part, the margin of a black colour; it is replete with grey vesicular molecules, and moves slowly.
E. ovato-cylindracea, interaneis manifestis mobilibus. Oval and cylindric enchelis, with visible moveable intestines.
The body is shaped like an egg, the fore-part narrow, and often filled with opake confused intestines; in moving, it elevates the fore-part of the body. It is found in the same water as the cyclidium glaucoma,No. 86, but is three times its size, and considerably more scarce.
E. cylindracea æqualis. Enchelis equally cylindric.
It is a cylindrical animalculum, twice as long as it is broad, the fore and hind-part of the same size; the intestines in the fore-part are pellucid, those in the hinder-part obscure. It moves by ascending and descending alternately. It may be seen sometimes swimming about with the extremities joined together. Found in water that has been kept for some days.
E. cylindracea, hyalina, margine nigricante. Cylindrical enchelis, transparent, with a blackish margin.
This animalculum forms an intermediate kind between the monas punctum, the enchelis seminulum, and the cyclidium milium. It is one of the smallest among the animalcula. The body is transparent, it has no visible intestines, the fore and hind-part are of an equal size, the edge of a deeper colour than the rest of the body; a point is to be seen in the middle of some of them; in others, it is as if a line passed through the middle.
E. cylindrico-ovato hyalina. Egg-shaped transparent enchelis.
A transparent, round, egg-shaped animalculum; nothing is discovered withinside, even by the third magnifier; but, with anincreased power, some long foldings may be seen on the superficies, and here and there a few bright molecules.
E. inverse conica, postice hyalina. Pear-form enchelis, the hinder-part transparent.
This enchelis is lively and pellucid, the fore-part is protuberant, and filled with molecules, the hinder-part smaller and empty; it has moveable molecular intestines. Its motion is rapid, passing backwards and forwards through the diameter of the drop. When at rest, it seems to have a little swelling, or tubercle, on the middle of the body.
E. ovato-cylindracea, gelatina. Oval enchelis, cylindrical, gelatinous.
This is also to be placed amongst the most minute animalcula; the end of it is rather pointed, and has a tremulous motion; it almost induces one to think it has a tail. Two of these little creatures may at times be perceived to adhere together. It was found in an infusion with the paramæcia aurelia,No. 93, and many other animalcula.
E. obovata, crystallina, medio coarctata. Sub-oval enchelis, crystalline, with a stricture in the middle.
An animalculum of an oval shape, the middle part drawn in, as if a string was tied round it. It is of a very small size, and is found in salt water.
E. elliptica, interaneorum congerie viridi. Of an elliptic shape, with a congeries of green intestines.
It is a round animalculum, pellucid, the fore-part obtuse, the hind-part rather sharp, marked with green spots; myriads may sometimes be seen wandering about in one drop; it is found among the green matter on the sides of the vessels in which water has been kept for some time.
E. cylindracea, utraque extremitate angustiore truncata. Cylindrical enchelis, both ends truncated.
The body is round and transparent, the fore and hind-part smaller than the rest of the body, and equally so, the ends a little truncated. In the inside a long and somewhat winding intestine, a sky-coloured bright fluid, and some black molecules transversely situated, may be discerned. The motions of this animalculum are languid; it was found in pure water.
A cylindric enchelis, the fore-part truncated.
This is one of the most transparent animalcula; the hinder-part of an obtuse convexity, the fore-part truncated. Müller suspects that there is a rotatory organ in the fore-part. No intestines can be seen. It runs backwards and forwards through the drop in a diametrical line, with a wavering motion; sometimes turns round for a moment, but presently enters on its usual course. Is found in an infusion of grass and hay.
E. elongata, antice obtusa, postice in caudam hyalinam attenuata,Plate XXV.Fig. 9. Enchelis with a long body, the fore-part obtuse, the hinder-part diminishing into a kind of tail.
The body is of a grey colour, pellucid, with globular molecules divided from each other, and dispersed through the whole body;the fore-part a, thick and obtuse, the hind-part b, crystalline and small, the end truncated. It is but seldom met with.
E. cylindrico-elongata, apice gracili subgloboso. Enchelis with a long cylindric body, the fore-part slender and roundish.
It is among the smaller animalcula, the body is cylindrical and bright, the hinder-part obtuse, the fore-part smaller, and terminating in a globule; a black line may now and then be perceived down the middle of it.
E. cylindracea, serie globulorum duplici, in collum hyalinum producta. Enchelis with a cylindrical body, the upper part prolonged into a transparent neck, a double series of globules running down the body. Its motion is slow, and generally in a straight line; it is found in ditch-water where the lemna thrives.
E. hyalina, antice angustata, apice globulari.Plate XXV.Fig. 11 and 12. Transparent enchelis, the fore-part rather smaller, and terminating in a small globule.
It has a gelatinous transparent body; no visible intestines, though a pellucid globule is discoverable near the hinder-part; the body is thickest in the middle, and grows smaller towards each end. It generally moves side-ways, sometimes in a retrograde manner; and if it be obstructed in its motion, draws itself up, as it is represented at Fig. 11.
E. cylindrica oblonga, obtusa, antice hyalina. Oblong cylindrical enchelis; the ends obtuse, the fore-part transparent.
The body is round, of an equal size throughout, and both ends obtuse; more than half the length is without any visible intestines, the lower end full of vesicular, pellucid, minute globules; a large globular vesicle is also to be found in the fore-part; it moves quickly from one side to the other, in a reeling or staggering manner. It was found in sea water.
E. cylindracea curvata utrinque truncata. A cylindric enchelis, crooked and truncated at both ends.
The body of this is cylindrical, about four times as long as broad, even, truncated at both ends, the intestines opake, and not to be distinguished from one another; it turns the extremities opposite ways, so as to form the figure of an S. It is to be found in water that has stood for some time, though but seldom. Joblot found it in an infusion of corn centaury or blue-bottle; it moves in an undulatory manner, but very slowly.
E. inverse conica, apicis altero angulo producto. Enchelis in the form of an inverted cone, one edge of the apex produced out so as to form an angle with the other part.
The body rather opake, of a grey colour, and of a long conical figure; the lower end obtuse, the fore-part thick, one side of this part projecting like a finger from the edge; two very small projections proceed also sometimes from the lower end. This animalculum has the power of retracting these projections, and making both ends appear obtuse. It moves about but slowly, and was found in water with the lemna minor, or least ducks-meat.
E. cylindrica, subcapitata.Plate XXV.Fig. 10. Cylindrical enchelis with a kind of head.
This is the largest of this kind of animalcula; the body is cylindrical, mucose, grey, long and rather opake, the fore-part globular, the hind-part obtuse. Something like three-teeth, c, may be sometimes seen to proceed from one of the sides; it can alter its shape considerably. Globules of different sizes may be seen within the body. It rolls about slowly from right to left.
E. elongata, medio papillula utrinque notata. A long enchelis, with two little nipples projecting from the middle of the body, one on each side.
It is long, round, and filled with grey molecules; the fore-part is obtuse and pellucid; a kind of neck or small contraction is formed at some little distance from this end. The lower part pointed; about the middle of the body there are two small projections.
E. cylindrica striata, apice hyalino spatulata. A cylindrical striated enchelis, the fore-part transparent, and of the shape of a spatula.
This animalculum is perfectly cylindrical, very pellucid, of a crystalline appearance; it is marked with very fine longitudinal furrows, and has generally two transparent globules, one placed below the middle, the other near the extremity of the body; on the other side are five smaller ones, which are oval. The top is dilated, with the corners rounded like the spatula, or instrument for spreading plaisters. It has a wavering kind of motion, folding the spatula variously, yet retaining its general form.Müller mentions his seeing it once draw the spatula into the body, and keep it there for two hours, when it again appeared.
A cylindric enchelis, the fore-part papillary.
The fore-part is protuberantly round, and rather opake, the hind-part pellucid, both extremities obtuse, furnished with a papillary finger-shaped head, the hinder part marked with a transparent circle, or circular aperture. The fore-part filled up with moveable molecules, which are more scarce in the hinder-part. It has a rotatory motion on a longitudinal axis, and moves through the water in an oblique direction. It is to be found in dunghill water in November and December.
E. ventricoso cylindrica, apice in papillam producta. Enchelis forming a kind of ventricose cylinder, with a small nipple proceeding from the apex.
It is not unlike the preceding animalculum, but is much larger; the anterior end not so obtuse, the nipple gradually formed from the fore-part, all but this end is opake, and filled with obscure particles: it has no transparent circle, as was observed in the enchelis pupula. Its motion is exceeding slow.
Vermis inconspicuus, simplicissimus, teres, elongatus. An invisible worm, very simple, round, and rather long.
V. linearis minutissimus. Very small linear vibrio.
This is one of the most minute animalcula, surpassing in slenderness the monas termo,No. 1. The greatest magnifier exhibits little more than a tremulous motion of myriads of little oblong obscure points. In a few days it almost fills the whole substance of the water in vegetable infusions.
V. linearis flexuosus. Vibrio like a bent line.
Myriads of this species may be found; it is between the vibrio lineola, just described, and the vibrio undula,No. 55. It appears as a little line, which is sometimes drawn up in an undulated shape, and moves backwards and forwards in a straight line, often without bending the body at all.
V. linearis, æqualis utrinque truncata. Linear vibrio, equally truncated at both ends.
This is an exceeding small creature, but visible with the third lens; in a certain position of the light, transparent. It is gelatinous, and not half so large as the monas lens,No. 5, though six, and sometimes ten times longer; it is everywhere of an equal size, and has no visible intestines; its action is languid, the serpentine flexures of the body are with great difficulty perceived. Müller made two infusions of hay in the same water, and at the same time, in the one he put the hay whole, in the other it was cut in small pieces; in the first there were none of the vibrio bacillus, but many of the monas lens and kolpoda cucullus,No. 108; in the latter, many of the vibrio bacillus, and few of the monæ.
V. filiformis flexuosus. A filiform flexuous vibrio.
A perfect undulating little line, round, gelatinous, without any visible intestines. It is never straight; when at rest it resembles the letter V, when in motion the letter M, or a bending line like that which geese form in their flight through the air; its motions are so rapid, that the eye can scarce follow them. It generally rests upon the top of the water, sometimes it fixes itself obliquely by one extremity, and whirls itself round. This is the little creature that Leeuwenhoeck says exceeds in slenderness the tail of the animalculum seminale, which he has described in Fig. 5, Epis. Phys. 41, being an hundred times less than a mustard-seed, and on which he makes the following very just observation: That as these very small animalcula can contract and variously fold their little tails, we must conclude that tendons and muscles are as necessary to them as to other animals; if to these we add the organs of sensation, and those of the intestines, the mind is lost in the astonishment which arises from the impression of infinite, in the indefinitely small.
V. filiformis, ambagibus in angulum obtusum productis. A filiform vibrio, the windings or flexures obtuse.
A slender gelatinous little animal, in the form of a long serpentine line, all the bendings being nearly equal in size, and at equal distances; it generally moves in a straight line; an intestine may be discovered down the middle. It is to be found in river water, but is not commonly to be met with.
V. filiformis, ambagibus in angulum acutum tornatis. Filiform vibrio, twisted something like a spiral wire or cork-screw, the bending acute.
It is an exceeding minute, singular creature, twisted in a spiral form; the shape of these bendings remains the same even when the animal is in motion, not occasioned by any internal force, but are its natural shape. It moves generally in a straight line, vibrating the hind and fore-parts. It was found in 1782, in an infusion of the sonchus arvensis, or corn sow-thistle.
V. tortuosus gelatinus. This little vibrio is twisted and gelatinous.
The body is white, or rather of a milky appearance, cylindric, long, the apex obtuse, rather growing smaller, and twisted towards the hind-part. Its motion is languid and undulatory, like that of the common worm; it sometimes moves quicker, but with seeming labour. When it bends itself alternately from one side to the other, a black long line may be discovered, sometimes whole, sometimes broken: when at rest, it occasionally twists into various folds. It may be observed easily with the first lens of the single microscope, and is probably the same animalculum mentioned by Leeuwenhoeck in all his works, as found in the dung of frogs, and in the spawn of the male libellula. It is to be found in marshy water in November, though but seldom.
V. gelatinosus, teres, antice angustatus. This vibrio is gelatinous, round, the fore-part small.
It is cylindric, milk-coloured, and slender towards the top, both ends obtuse; no traces of intestines to be discovered, though four or five spherical eggs are perceived at the extremity of the hind-part. It can draw the fore-part so much inwards as to give it a truncated and dilated appearance, something like a spatula. Its motion is slow and progressive. It is found in marshy waters.
V. linearis, æqualis, utraque extremitate truncata, globulis binis mediis. Linear vibrio, of an equal size throughout, both ends truncated, and two small globules in the middle of the body.
It is of a small size, and rather less than the following animalculum; the body is of a pellucid talc-like appearance, the fore and hind-part truncated; in the middle are two (sometimes there is only one) pellucid globules, placed lengthwise. It most commonly moves forward in a straight line; its movements are slow. It was found in fetid salt water.
V. linearis, utrinque attenuatus, globulis tribus, extremis minoribus. Linear vibrio, both the ends smaller than the middle, furnished with three globular points, the two which are at the extremities being smaller than that at the middle.
The body is pellucid, talky, each of the ends rather tapering, furnished with three pellucid globules, the middle one is the largest; the space between these globules is generally filled with a green matter; in some there is nothing of the green substance near the extremities, but only about the middle. It seldom moves far, and then its motion is rectilinear, backwards and forwards.
V. flavescens paleis gregariis multifariam ordinatis.Plate XXV.Fig. 13, 14, 15. Yellow, gregarious, straw-like vibrio.
This is a wonderful animalculum, or rather a congeries of animalcula. It is invisible to the naked eye, and consists of a transparent membrane, with yellow intestines, and two or threevisible points; they are generally found collected together in different parcels, from seven to forty in number, and ranged in a variety of forms, sometimes in a straight line, as in Fig. 14, then forming the concave Figure 13, at others, moving in a zig-zag direction, as in Fig. 15; when at rest they are generally in a quadrangular form, and found in great plenty with the ulva latissima, or brown laver.
As this animalculum seems to have some affinity with the hair-like animal of Baker, I think the reader will be better pleased to see his description of it introduced in this place, than to have it raised into a new and distinct species.
This little animal is extremely slender, and not uncommonly one-hundred and fifty times longer than broad. Its resemblance to an hair induced Baker to call it the hair-like insect. The body or middle part, which is nearly straight, appears in some composed of such parallel rings as the windpipe of land animals consists of, but seems in others scaled, or rather made up of rings that obliquely cross each other. Its two ends are bent or hooked, pretty nearly in the same degree, but in a direction contrary each to the other; and as no eyes can be discerned, it is difficult to judge which is the head or tail. Its progressive motion differs from that of all animals hitherto described; for, notwithstanding the body is composed of many rings and joints, it seems unable to bend them, or move directly forwards; but when it is inclinable to change its quarters, it can move from right to left, or left to right, and proceed at the same time backwards or forwards obliquely; and this it performs by turning upon one end as a center, and describing with the other the quarter of a circle; then it does the same with the other end, and so alternately; whereby its progression is in a diagonal line, or from corner to corner. Of this any one may immediately be satisfied, who willtake the trouble of shifting the points of a pair of compasses in that manner. All its motions are extremely slow, and require much patience and attention in the observer. It has neither feet, fins, nor hairs, but appears perfectly smooth and transparent, with the head bending one way, and the tail another, so as to be like a long Italic S; nor is any internal motion, or particularly opake part, to be perceived, which may determine one to suppose it either the stomach, or the intestines.