Part 36

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, see p. 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.

6. MONAS MICA. 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.

7. MONAS TRANQUILLA. 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.

8. MONAS LAMELLULA. 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.

9. MONAS PULVISCULUS. 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.

10. MONAS UVA. 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.

II. PROTEUS.

Vermis inconspicuus, simplicissimus, pellucidus, mutabilis. An invisible, very simple, pellucid worm, of a variable form.

11. PROTEUS DIFFLUENS. 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.

12. PROTEUS TENAX. 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.

III. VOLVOX.

Volvox inconspicuus, simplicissimus, pellucidus, sphæricus. An invisible, very simple, pellucid, spherical worm.

13. VOLVOX PUNCTUM. 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.

14. VOLVOX GRANULUM. 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 found generally in the month of June, in marshy places; it moves but slowly.

15. VOLVOX GLOBULUS. 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.

16. VOLVOX PILULA. 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.

17. VOLVOX GRANDINELLA. 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.

18. VOLVOX SOCIALIS. 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.

19. VOLVOX SPHÆRICULA. 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.

20. VOLVOX LUNULA. 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.

21. VOLVOX GLOBATOR. 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 waters in 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.

22. VOLVOX MORUM. 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. The globules 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.

23. VOLVOX UVA. 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.

24. VOLVOX VEGETANS. 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; but afterwards 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.

IV. ENCHELIS.

Vermis inconspicuus, simplicissimus, cylindraceus. An invisible, simple, cylindric worm.

25. ENCHELIS VIRIDIS. 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.

26. ENCHELIS PUNCTIFERA. 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-part _a_, 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.

27. ENCHELIS DESES. 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.

28. ENCHELIS SIMILIS. 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.

29. ENCHELIS SEROTINA. 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.

30. ENCHELIS NEBULOSA. 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.

31. ENCHELIS SEMINULUM. 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.

32. ENCHELIS INTERMEDIA. 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.

33. ENCHELIS OVULUM. 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 an increased power, some long foldings may be seen on the superficies, and here and there a few bright molecules.

34. ENCHELIS PIRUM. 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.

35. ENCHELIS TREMULA. E. ovato-cylindracea, gelatina. Oval enchelis, cylindrical, gelatinous.