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.
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 to ³⁄₁₀₀₀₀₀ of 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 fraction ³⁄₁₀₀₀₀₀, that is, by the number
²⁷⁄₁₀₀₀₀₀₀₀₀₀₀₀₀₀₀₀, 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.
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.
A
METHODICAL DIVISION
OF THE
ANIMALCULA INFUSORIA.
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. MONAS.
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.
1. MONAS TERMO. 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.
2. MONAS ATOMUS. 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.
3. MONAS PUNCTUM. 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.
4. MONAS OCELLUS. 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 moves
irregularly, is found in ditches covered with conferva, and frequently
with the cyclidium milium, see No. 84.
5. MONAS LENS. 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, 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.