magnifying glass, being about one-thirtieth of an inch in length, and
one-hundred and fortieth broad. Fig. 5 represents one of them magnified
about one-hundred and twenty times; they are in general of a bright
chesnut colour, the extremity _a b_ is whiter and more transparent than
the rest of the body. The end _a_ is rather round, the end _c_ is
pointed. A distinguishing mark of these little creatures is a row of
transparent globules, which are placed at intervals through the whole
length of the body, beginning at _b_, where the transparency of the
fore-part ceases, and going on towards the extremity _c_. They are in
diameter rather less than one-third of the body. Another peculiar mark
is a small lunular space _d_, near the middle of the body. This part is
transparent, and is free from the coloured matter of the intestines;
there is a neck in the intestines near this space, which confines them
to one part of the body.
Great care should be taken by the observer, not to burst the skin of the
eels in disengaging them from the grain, for they never break or burst
of themselves; but if broke, visible intestines, filled with a black
matter, rush out of the body, from which little black globules are
disengaged; if the observation be made immediately after these globules
proceed from the eel, they swim slowly about the water, though divested
of any principle of internal motion; but if the eels that are broke be
left long in the water, the same phænomena will take place, as in other
animal and vegetable infusions. The want of due attention to these
circumstances has been productive of many of the fanciful positions of
Needham, which were deduced from ill-conducted experiments; and,
consequently, when properly examined, are found to be in a great measure
false.
M. Roffredi sowed some of the grains of this wheat, which sprang up; but
the ear was either wholly or in a great measure spoiled, being filled
with these eels. He also found them in other parts of the plant; in
order to disengage them, the plant must be soaked in water, and then
compressed a little. At first sight these eels seem to resemble the
foregoing, but a more accurate inspection shews that they have neither
the same curious disposition of the internal globules, nor the
transparent place in the middle of the body. The intestinal bag leaves
indeed in these an empty space, but it is of an undetermined form. The
animalcula from the plant are much more lively than those which are
procured from the dried grains.
The principal phænomena in this kind of blighted wheat is probably owing
to these animalcula, who prevent the regular circulation of the sap.
They increase in size in a certain proportion to the plant, so that at
last they may be observed with great ease by the naked eye, being
two-tenths of an inch long, and nearly one-tenth in diameter. Fig. 4
represents one of these magnified nearly in the same proportion as Fig.
5; _a a a a_, the ovary, which may be traced almost from the lower
extremity to the middle of the body, where the body becomes so opake as
to prevent its being seen any further. The eggs, when arrived at their
full growth, are nearly of a cylindric shape, both ends rounded; towards
the extremity _b_ there are two little protuberances _d d_, through
which the eggs are most probably extruded; these protuberances are not
always visible. The eggs are formed of a fine transparent membrane; it
covers the young eel, which is folded curiously therein; these eggs may
be frequently found in the plant.
A most satisfactory view of these eels is obtained by examining them
with the solar microscope; it affords one of the most surprizing and
magnificent spectacles; two generations may be often seen, one, which
draws near the allotted period of its existence, and another which only
begins to enjoy the blessings of life: some arrived at their full
growth, and others quite small. In some we may perceive the young
animalcula in motion in the eggs, in others, no such motion can be
observed; with a variety of other circumstances too tedious to
enumerate, though they afford great pleasure to the spectator.
One of the most remarkable circumstances in these animalcula is the
faculty they have of receiving again the powers of life, after having
lost them for a considerable time; for instance, when some of these
blighted grains, that have been preserved for many years, have been
soaked in water for ten or twelve hours, living eels of this species
have been found in it; if the water evaporate, or begin to fail, they
cease to move, but, on a fresh application, will be again revived.[125]
[125] The property of revivification is not confined to this species,
being common to other kinds of worms, and it is not improbable that
the hydræ may possess the same faculty. EDIT.
It may be proper to notice here, that according to the observations of
Roffredi, those eels which have done laying of eggs are incapable of
being resuscitated upon being moistened; the same seems to be also the
case with those that are very young; it is probable they must attain a
certain age and degree of strength before they are endowed with this
wonderful faculty.
In the month of August, 1743, a small parcel of blighted wheat was sent
by Mr. Needham to Martin Folkes, Esq. President of the Royal Society,
with an account of his then new discovery; which parcel the president
was pleased to give to Mr. Baker, desiring him to examine it carefully.
In order so to do, he cut open some of the grains that were become dry,
took out the fibrous matter, and applied water to it on a slip of glass,
but could discern no other motion than a separation of the fibres or
threads, which separation he imputed wholly to an elasticity in the
fibres; and perceiving no token of life, after watching them with due
care, and repeating the experiment till he was weary, an account thereof
was written to Needham, who, having by trials of his own, found out the
cause of this bad success, advised him to steep the grains before he
attempted to open them; on doing which he was very soon convinced of his
veracity, and entertained with the pleasing sight of this wonderful
phænomenon. At different times after this, Baker made experiments with
grains of the same parcel, without being once disappointed. He soaked a
couple of grains in water for the space of thirty-six hours, when,
believing them sufficiently moistened, he cut one open, and applying
some of the fibrous substance to the microscope in a drop of water, it
separated immediately, and presented multitudes of the anguillulæ
without the least motion or sign of life; but being taught by experience
that they might notwithstanding possibly revive, he left them for about
four hours, and then examining them again, found much the greatest
number moving their extremities pretty briskly, and in an hour or two
after they appeared as lively as these creatures usually are. Mr. Folkes
and some other friends were witnesses of this experiment. We find an
instance here that life may be suspended and seemingly destroyed; that
by an exhalation of the fluids necessary to a living animal, the
circulations may cease, all the organs and vessels of the body may be
shrunk up, dried, and hardened; and yet, after a long while, life may
begin anew to actuate the same body, and all the animal motions and
faculties may be restored, merely by replenishing the organs and vessels
with a fresh supply of fluid. Here is a proof that the animalcula in the
grains of blighted wheat can endure having their bodies quite dried up
for the space of four years together, without being thereby deprived of
the property of resuscitation.
It appears plainly from the foregoing experiments, that when the
blighted grains of wheat have been kept a long time, and the bodies of
these animalcula are consequently become extremely dry, the rigidity of
their minute vessels requires to be relaxed very gently, and by
exceeding slow degrees; for we find that, on the application of water
immediately to the bodies of these animalcula, when taken from the dry
grains, they do not so certainly revive, as they do if the grains
themselves be either buried in earth, or steeped in water for some time
before they are taken out: the reason of which most probably is, that
too sudden a relaxation bursts their delicate and tender organs, and
thereby renders them incapable of being any more employed to perform the
actions of life; and, indeed, there are always some dead ones amongst
the living, whose bodies appear bursten, or lacerated, as well as others
that lie extended and never come to life.
Some discretion is needful to adapt the time of continuing the grains in
water or earth to the age and dryness of them; for if they be not opened
before they have been too much or too long softened, the animalculum
will not only seem dead, but will really be so. Of the two grains
mentioned to have been four years old when put to soak, one was opened
after it had lain thirty-six hours, and the event proved as already
related; the other was suffered to lie for above a week, on opening
which, all the anguillulæ near the husk were found dead, and seemingly
in a decayed condition; but great numbers issued alive from the middle,
and moved themselves briskly. Unless the husks be opened to let these
creatures out after being steeped, they all inevitably perish; and when
taken out and preserved in water, if the husks be left with them, they
will die in a few days; but otherwise, continue alive in water for
several months together; and, should the water evaporate, may be revived
again by giving them a fresh supply.
72. VIBRIO LINTER. V. ventricoso-ovatus, collo brevissimo. Ventricose
oval vibrio, with a short neck.
This is one of the larger animalcula, of an egg-shape, pellucid,
inflated, somewhat depressed at top; the apex is prolonged into a
moveable crystalline neck, the belly is replete with pellucid molecules.
It is not very common, though occasionally to be found among the lemnæ.
73. VIBRIO UTRICULUS. V. teres, antice angustatus truncatus, postice
ventricosus. Round vibrio, the fore-part narrow and truncated, the lower
ventricose.
It does not ill resemble a bottle in shape; the belly is replete with
molecular intestines, the neck bright and clear, the top truncated; in
some a pellucid point is visible at the bottom of the belly. It is in an
unceasing, vehement, and vacillatory motion, the neck moving from one
side to the other as fast as possible.
74. VIBRIO FASCIOLA. V. antice attenuatus, medio latiusculus, postice
acutus. Vibrio with a small fore-part, the middle a little bigger, the
hind-part acute.
This is a pellucid animalculum, in the middle are the intestines in the
form of points; an alimentary pipe, which lessens gradually in size, is
also perceptible. The motion of it is quick, darting itself up and down
in the water with great velocity. It is found in water just loosened
from the frost, and seldom elsewhere.
75. VIBRIO COLYMBUS. V. crassus, postice acuminatus, collo subfalcato.
Thick vibrio, sharpened at the end, the neck a little bent.
It is larger than most of the vibrios, and not unlike a bird in shape.
The neck is round, shorter than the trunk, of an equal size throughout,
and of a bright appearance, the apex obtuse. The trunk is thick,
somewhat triangular, full of yellow molecules; the fore-part broad, the
hinder-part acute, the motion slow.
76. VIBRIO STRICTUS. V. elongatus linearis, anticem versus attenuatus,
apice obtuso. Vibrio lengthened out almost to a line, small towards the
fore-part, the apex obtuse.
The body linear, being a bright membranaceous thread, without any
flexure; the hind-part somewhat thicker, round, and filled with
molecules, excepting just at the end, where there is a small pellucid
empty space. The apex is obtuse, and rather globose; it has a power of
contracting and drawing in the filiform part.
77. VIBRIO ANAS. V. oblongus, utroque fine attenuatus, collo cauda
longiore. Oblong vibrio, both ends attenuated, the neck longer than the
tail.
The trunk is oblong, opake, and filled with molecules. Both the fore and
the hind-part is prolonged into a pellucid talky membrane, which the
animalculum has a power of retracting at pleasure. The tail is more
acute than the neck. It is most generally found in salt water; a species
of them have been found in river water, with a longer neck.
78. VIBRIO CYGNUS. V. ventricosus, collo adunco. Corpulent vibrio, with
a crooked neck.
This animalculum is little more than a most pellucid line, crooked at
top, prominent in the middle, and sharp at the end; the fore-part, or
neck, is equal in length to the rest of the body, and three times longer
than the hind-part or tail; the intermediate part swelling out, is full
of dark-coloured molecules and pellucid intestines. It is very small,
and the most slothful of all those which move and advance their necks.
79. VIBRIO ANSER. V. ellipticus, collo longo, tuberculo dorsali. Plate
XXV. Fig. 27 and 29. Elliptical vibrio, with a long neck, and a little
lump on the back.
It is between the vibrio proteus and vibrio falx, and is distinguished
by the lump _b_, Fig. 29, on the back, placed behind the neck; from this
an even long neck, _a_, proceeds. The trunk, _d_, is elliptic, round,
and without any lateral inequality; full of molecules, the hind-part,
_e_, sharp and bright, the fore-part produced into a bending neck that
is longer than the body; the apex even and whole, with blue canals
passing between the marginal edges, occupying the whole length of the
neck; in one of them a vehement descent of water to the beginning of the
trunk is perceivable. The motion of the body is slow, that of the neck
is more lively and flexuous, sometimes spiral. It is found in water
where duck-weed grows.
80. VIBRIO OLOR. V. ellipticus, collo longissimo, apice nodoso. Plate
XXV. Fig. 28. Elliptical, with a very long neck, and a knob on the apex.
The form of the body is elliptical and ventricose, the hind-part
somewhat sharp. It is membranaceous, dilatable, winding variously; the
hind-part is sometimes replete with darkish molecules. The neck, _d_, is
three or four times longer than the body, of an equal size throughout,
except a small degree of thickness at the apex, _f_, very pellucid. The
motion of its neck is very lively, that of the body slow. It is found in
water that has been kept for a long time, and which has acquired a
vegetable greenness.
81. VIBRIO FALX. V. gibbosus, postice obtusus, collo falcato. A gibbous
vibrio, the hind-part obtuse, the neck crooked.
The body is pellucid, elliptical, the fore-part lessening into a little
round bright neck, nearly of the same length as the trunk, the hind-part
obtuse. The trunk itself is rather rounding or tending to the gibbous,
and filled with very small molecules; there are also two bright
globules, one within the hind extremity, the other in the middle of the
body. The neck being immoveable, the motions of the animalculum somewhat
resemble those of a scythe.
82. VIBRIO INTERMEDIUS. V. membranaceus, antice attenuatus, postice
subacutus. Membranaceous vibrio, the fore-part small, the hinder part
somewhat acute.
It seems to be an intermediate species between the preceding vibrio and
the fasciola, No. 74; it is a thin membrane, constantly folded. The
whole of it has a crystalline talky appearance, the middle replete with
grey particles of different sizes; it has all round a distinct bright
margin; the apex of the neck is truncated, the tail obtuse.
VI. CYCLIDIUM.
Vermis inconspicuus, simplicissimus, pellucidus, complanatus,
orbicularis vel ovatus. A simple, invisible, flat, pellucid, orbicular
or oval worm.
83. CYCLIDIUM BULLA. C. orbiculare hyalinum. Orbicular bright cyclidium.
A very pellucid white animalculum, or orbicular skin, the edges a little
darker than the rest. By the assistance of the compound microscope, some
globular intestines of a very crystalline appearance are just
perceptible. Its motion is slow and semicircular. It is found
occasionally in an infusion of hay.
84. CYCLIDIUM MILIUM. C. ellipticum crystallinum. Elliptic and
crystalline cyclidium.
It is very pellucid, of a crystalline splendour, membranaceous and
elliptical; a line may be perceived through the whole length of it, a
point in the fore-part, the hinder-part getting darker. Its motion is
swift, fluttering, and interrupted; probably both extremities are
ciliated.
85. CYCLIDIUM FLUITANS. C. ovale crystallinum. Oval crystalline
cyclidium.
This is one of the smallest animalcula. The body of an oval, or rather
suborbicular shape, depressed, crystalline; two small blue spaces may
be discovered by the assistance of the microscope at the sides of this
little creature.
86. CYCLIDIUM GLAUCOMA. C. ovatum, interaneis ægre conspicuis. Oval
cyclidium, the intestines perceived with difficulty.
A pellucid oval body, with both ends plain, or an oval membrane, with a
distinct well-defined edge; the intestines are so transparent that they
can scarce be discerned, when it is empty; when full, they are of a
green colour, and there are dark globules discoverable in the middle.
In plenty of water it moves swiftly in a circular and diagonal
direction; whenever it moves slowly it seems to be taking in water, the
intestines are then also in a violent commotion. Two of the smaller ones
may often be perceived cohering to each other, and drawing one another
by turns; nor are they separated by death, for they remain united even
when the water is evaporated. Those who are not familiar with these
kinds of observations, may easily mistake the shade in a single one for
a junction of two, or the junction of two for a copulation, for they
generate by division.
87. CYCLIDIUM NIGRICANS. C. oblongiusculum, margine nigricans. Oblong
cyclidium, with a black margin.
It is very small, pellucid, and flat. With a small magnifier, it may be
mistaken for an enchelis.
88. CYCLIDIUM ROSTRATIUM. C. ovale, antice mucronatum. An oval
cyclidium, the fore-part pointed.
This is an oval, smooth, and very pellucid animalculum, with the
fore-part running out into an obtuse point; with this it seems to feel
and examine the bodies which it approaches. It is probably ciliated,
though the hairs have not been discovered.
The intestines are filled with a blue liquor, forming in a tube, which,
from the aperture to the middle of the body, is divided into two legs or
branches; beyond the middle there are two little transverse blue lines.
This colour sometimes vanishes, and then they seem to be composed of
vesicles.
89. CYCLIDIUM NUCLEUS. C. ovale, postice acuminatum. An oval cyclidium,
the hind-part pointed.
The body is pellucid, depressed, the fore-part obtusely convex, the
hind-part acute, the intestines vesicular, the fore and hind-part on
each side dark. It resembles a grape-seed.
90. CYCLIDIUM HYALINUM. C. ovatum, postice acutum. Oval cyclidium, the
hind-part acute.
This cyclidium is oval, flat, and bright, without any visible
intestines, the hinder-part somewhat smaller than the fore-part; it has
a tremulous kind of motion.
91. CYCLIDIUM PEDICULUS. C. ovale convexum, subtus planum. An oval
convex cyclidium, the bottom even. Trembley Polyp. 1, p. 282.
This is a gelatinous white animalculum, the bottom gibbous over the
back, the extremities depressed and truncated, with one end sometimes
apparently cloven into two; perhaps this is the aperture of the mouth.
It is scarce ever seen but on the arms and the body of the hydra
pallida, upon which it runs as if it had feet.
92. CYCLIDIUM DUBIUM. C. ovale, supra convexum, subtus cavum. Oval
cyclidium, the upper part convex, the under part concave.
This is one of the larger species, the margin is pellucid, and the inner
part contains a great number of black molecules.
VII. PARAMÆCIUM.
Vermis inconspicuus, simplex, pellucidus, membranaceus, oblongus. An
invisible, simple, membranaceous, flat, and pellucid worm.
93. PARAMÆCIUM AURELIA. VOLVOX TEREBELLA. ELLIS. P. compressum, versus
anticem plicatum, postice acutum. Compressed paramæcium, oblong, folded
towards the fore-part, the hinder-part acute.
This is rather a large animalculum, membranaceous, pellucid, and four
times longer than it is broad; the fore-part obtuse, transparent,
without intestines; the hind-part replete with molecules of various
sizes; the fold, which goes from the middle to the apex is a striking
characteristic of the species, forming a kind of triangular aperture,
and giving it somewhat the appearance of a gimblet. Its motion is
rectilinear, reeling or staggering, and generally vehement.
They are frequently found cohering lengthwise; the lateral edges of both
bodies appear bright. They may also sometimes be seen lying on one
another alternately, at others, adhering by the middle. They will live
many months in the same water without its being renewed. They are to be
found in June in ditches where there is plenty of duck-weed.
94. PARAMÆCIUM CHRYSALIS. P. cylindraceum, versus anticam plicatum,
postice obtusum. Plate XXV. Fig. 26. Cylindrical paramæcium, folded
towards the fore-part, the hinder-part obtuse.
It differs very little from the preceding, only the ends, _a b_, are
more obtuse, and the margins filled with black globules. It is an
inhabitant of salt water.
95. PARAMÆCIUM VERSUTUM. P. cylindraceum, postice incrassatum, utraque
extremitate obtusum. Cylindrical paramæcium, the lower part thick, and
both ends very obtuse.
An oblong, green, and gelatinous body, filled with molecules; the
lower-part thick, the fore-part smaller, both ends obtuse, and may be
seen to propagate by division. It is found in ditches.
96. PARAMÆCIUM OVIFERUM. P. depressum, intus bullis ovalibus. Plate XXV.
Fig. 25. Depressed paramæcium, with large oval molecules withinside.
A membranaceous, oval, oblong animalculum, grey and pellucid, having
many oval very pellucid corpuscles, _a_, dispersed about the body, and
many black grains towards _b_.
97. PARAMÆCIUM MARGINATUM. P. depressum, griseum, margine duplici. Plate
XXV. Fig. 24. Depressed paramæcium, grey, with a double margin.
This is one of the largest of the class, flat, elliptical, every part
filled with molecules, except in the lower end, _b_, where there is a
pellucid vesicle; this animalculum is surrounded by a broad double
margin; when expiring, a bright spiral intestine is observable. _a_, the
apex; _b_, the vesicle; _c_, the spiral intestine.
VIII. KOLPODA.
Vermis inconspicuus, simplicissimus, pellucidus, complanatus, sinuatus.
An invisible, very simple, pellucid, flat and crooked worm.
98. KOLPODA LAMELLA. K. elongata, membranacea, antice curvata.
This animalculum resembles a long, narrow, and pellucid membrane, the
hind-part obtuse, narrower, and curved towards the top; no intestines
discoverable, only a ridge or fold going through the middle. Its motion
is reeling or staggering, and very singular, moving to and fro on its
edge, not on the flat side, as is usual with most microscopic animals.
It is found in water, but is very seldom to be met with.
99. KOLPODA GALLINULA. K. oblonga, dorso antico membranaceo hyalino.
Oblong kolpoda, the back towards the fore-part bright and membranaceous.
The apex rather bent; the belly oval, convex and striated. It is found
in fetid salt water.
100. KOLPODA ROSTRUM. K. oblonga, antice uncinata. Oblong, the fore-part
hooked.
The fore-part is bent into a kind of hook; the hind-part is obtuse, and
everywhere filled with black molecules. One of the edges from the
fore-part to the middle, is often so blunted and dilated, that the rest
of the body appears quite smooth, and that part thick and triangular. It
has a slow and horizontal motion. It is to be found, though but seldom,
in water where the lemnæ grow.
101. KOLPODA OCHREA. K. elongata, membranacea, apice attenuato, basi in
angulum rectum producta. Long kolpoda, membranaceous, the apex
attenuated, the base bent in a right angle to the body.
A large animalculum, long, and of a singular figure, depressed,
membranaceous, flexible; one edge nearly straight, the other somewhat
bent, filled with obscure molecules, and a few little bladders dispersed
here and there; the apex bright and small, the base projecting like the
human foot from the leg.