29 Oestrus or Gadfly.
33 Ichneumon fly.
37 Libellula.
39 Bees.
57 Shark.
59 Crocodile
66 Animals prey on Vegetables.
71 Defect of Stimulus.
87 Theatric Preachers.
93 Pleasure of Life, Ennui.
94 Of Tooth-edge.
119 Epidemic Complaints.
130 Compassion may be too great.
147 Doctrine of Atoms.
160 Pleasure of viewing a Landscape.
178 Pleasure from Music.
242 Ancient Orators spoke disrespectfully of the mechanic
Philosophers.
270 Influence of Printing.
299 Associated ideas of three Classes.
309 Wit defined.
349 Surprising number of Seeds.
351 Of the Aphis, its Numbers.
352 Aphis drinks the Sap-juice.
359 The Mutation of the Tadpole.
387 Animation near the Surface of the Earth.
387 All dead animal and vegetable Bodies become animated.
403 Doctrine of St. Paul.
411 Happiness increased.
417 Doctrine of Pythagoras.
431 Geology.
450 Method of investigation of Organic happiness.
453 Organic Life increases.
ADDITIONAL NOTES.
ADDITIONAL NOTES.
SPONTANEOUS VITALITY OF MICROSCOPIC ANIMALS.
Hence without parent by spontaneous birth
Rise the first specks of animated earth.
CANTO I. l. 227.
_Prejudices against this doctrine._
I. From the misconception of the ignorant or superstitious, it has
been thought somewhat profane to speak in favour of spontaneous vital
production, as if it contradicted holy writ; which says, that God
created animals and vegetables. They do not recollect that God created
all things which exist, and that these have been from the beginning in
a perpetual state of improvement; which appears from the globe itself,
as well as from the animals and vegetables, which possess it. And
lastly, that there is more dignity in our idea of the supreme author
of all things, when we conceive him to be the cause of causes, than
the cause simply of the events, which we see; if there can be any
difference in infinity of power!
Another prejudice which has prevailed against the spontaneous production
of vitality, seems to have arisen from the misrepresentation of this
doctrine, as if the larger animals had been thus produced; as Ovid
supposes after the deluge of Deucalion, that lions were seen rising out
of the mud of the Nile, and struggling to disentangle their hinder
parts. It was not considered, that animals and vegetables have been
perpetually improving by reproduction; and that spontaneous vitality was
only to be looked for in the simplest organic beings, as in the smallest
microscopic animalcules; which perpetually, perhaps hourly, enlarge
themselves by reproduction, like the roots of tulips from seed, or the
buds of seedling trees, which die annually, leaving others by solitary
reproduction rather more perfect than themselves for many successive
years, till at length they acquire sexual organs or flowers.
A third prejudice against the existence of spontaneous vital
productions has been the supposed want of analogy; this has also
arisen from the expectation, that the larger or more complicated
animals should be thus produced; which have acquired their present
perfection by successive generations during an uncounted series of
ages. Add to this, that the want of analogy opposes the credibility of
all new discoveries, as of the magnetic needle, and coated electric
jar, and Galvanic pile; which should therefore certainly be well
weighed and nicely investigated before distinct credence is given
them; but then the want of analogy must at length yield to repeated
ocular demonstration.
_Preliminary observations._
II. Concerning the spontaneous production of the smallest microscopic
animals it should be first observed, that the power of reproduction
distinguishes organic being, whether vegetable or animal, from
inanimate nature. The circulation of fluids in vessels may exist in
hydraulic machines, but the power of reproduction belongs alone to
life. This reproduction of plants and of animals is of two kinds,
which may be termed solitary and sexual. The former of these, as in
the reproduction of the buds of trees, and of the bulbs of tulips, and
of the polypus, and aphis, appears to be the first or most simple mode
of generation, as many of these organic beings afterwards acquire
sexual organs, as the flowers of seedling trees, and of seedling
tulips, and the autumnal progeny of the aphis. See Phytologia.
Secondly, it should be observed, that by reproduction organic beings
are gradually enlarged and improved; which may perhaps more rapidly
and uniformly occur in the simplest modes of animated being; but
occasionally also in the more complicated and perfect kinds. Thus the
buds of a seedling tree, or the bulbs of seedling tulips, become
larger and stronger in the second year than the first, and thus
improve till they acquire flowers or sexes; and the aphis, I believe,
increases in bulk to the eighth or ninth generation, and then produces
a sexual progeny. Hence the existence of spontaneous vitality is only
to be expected to be found in the simplest modes of animation, as the
complex ones have been formed by many successive reproductions.
_Experimental facts._
III. By the experiments of Buffon, Reaumur, Ellis, Ingenhouz, and
others, microscopic animals are produced in three or four days,
according to the warmth of the season, in the infusions of all
vegetable or animal matter. One or more of these gentlemen put some
boiling veal broth into a phial previously heated in the fire, and
sealing it up hermetically or with melted wax, observed it to be
replete with animalcules in three or four days.
These microscopic animals are believed to possess a power of
generating others like themselves by solitary reproduction without
sex; and these gradually enlarging and improving for innumerable
successive generations. Mr. Ellis in Phil. Transact. V. LIX. gives
drawings of six kinds of animalcula infusoria, which increase by
dividing across the middle into two distinct animals. Thus in paste
composed of flour and water, which has been suffered to become
acescent, the animalcules called eels, vibrio anguillula, are seen in
great abundance; their motions are rapid and strong; they are
viviparous, and produce at intervals a numerous progeny: animals
similar to these are also found in vinegar; Naturalist's Miscellany by
Shaw and Nodder, Vol. II. These eels were probably at first as minute
as other microscopic animalcules; but by frequent, perhaps hourly
reproduction, have gradually become the large animals above described,
possessing wonderful strength and activity.
To suppose the eggs of the former microscopic animals to float in the
atmosphere, and pass through the sealed glass phial, is so contrary to
apparent nature, as to be totally incredible! and as the latter are
viviparous, it is equally absurd to suppose, that their parents float
universally in the atmosphere to lay their young in paste or vinegar!
Not only microscopic animals appear to be produced by a spontaneous
vital process, and then quickly improve by solitary generation like
the buds of trees, or like the polypus and aphis, but there is one
vegetable body, which appears to be produced by a spontaneous vital
process, and is believed to be propagated and enlarged in so short a
time by solitary generation as to become visible to the naked eye; I
mean the green matter first attended to by Dr. Priestley, and called
by him conferva fontinalis. The proofs, that this material is a
vegetable, are from its giving up so much oxygen, when exposed to the
sunshine, as it grows in water, and from its green colour.
Dr. Ingenhouz asserts, that by filling a bottle with well-water, and
inverting it immediately into a basin of well-water, this green
vegetable is formed in great quantity; and he believes, that the water
itself, or some substance contained in the water, is converted into
this kind of vegetation, which then quickly propagates itself.
M. Girtanner asserts, that this green vegetable matter is not produced
by water and heat alone, but requires the sun's light for this
purpose, as he observed by many experiments, and thinks it arises from
decomposing water deprived of a part of its oxygen, and laughs at Dr.
Priestley for believing that the seeds of this conferva, and the
parents of microscopic animals, exist universally in the atmosphere,
and penetrate the sides of glass jars; Philos. Magazine for May 1800.
Besides this green vegetable matter of Dr. Priestley, there is another
vegetable, the minute beginnings of the growth of which Mr. Ellis
observed by his microscope near the surface of all putrefying
vegetable or animal matter, which is the mucor or mouldiness; the
vegetation of which was amazingly quick so as to be almost seen, and
soon became so large as to be visible to the naked eye. It is
difficult to conceive how the seeds of this mucor can float so
universally in the atmosphere as to fix itself on all putrid matter in
all places.
_Theory of Spontaneous Vitality._
IV. In animal nutrition the organic matter of the bodies of dead
animals, or vegetables, is taken into the stomach, and there suffers
decompositions and new combinations by a chemical process. Some parts
of it are however absorbed by the lacteals as fast as they are
produced by this process of digestion; in which circumstance this
process differs from common chemical operations.
In vegetable nutrition the organic matter of dead animals, or
vegetables, undergoes chemical decompositions and new combinations on
or beneath the surface of the earth; and parts of it, as they are
produced, are perpetually absorbed by the roots of the plants in
contact with it; in which this also differs from common chemical
processes.
Hence the particles which are produced from dead organic matter by
chemical decompositions or new consequent combinations, are found
proper for the purposes of the nutrition of living vegetable and
animal bodies, whether these decompositions and new combinations are
performed in the stomach or beneath the soil.
For the purposes of nutrition these digested or decomposed recrements
of dead animal or vegetable matter are absorbed by the lacteals of the
stomachs of animals or of the roots of vegetables, and carried into
the circulation of their blood, and these compose new organic parts to
replace others which are destroyed, or to increase the growth of the
plant or animal.
It is probable, that as in inanimate or chemical combinations, one of
the composing materials must possess a power of attraction, and the
other an aptitude to be attracted; so in organic or animated
compositions there must be particles with appetencies to unite, and
other particles with propensities to be united with them.
Thus in the generation of the buds of trees, it is probable that two
kinds of vegetable matter, as they are separated from the solid
system, and float in the circulation, become arrested by two kinds of
vegetable glands, and are then deposed beneath the cuticle of the
tree, and there join together forming a new vegetable, the caudex of
which extends from the plumula at the summit to the radicles beneath
the soil, and constitutes a single fibre of the bark.
These particles appear to be of two kinds; one of them possessing an
appetency to unite with the other, and the latter a propensity to be
united with the former; and they are probably separated from the
vegetable blood by two kinds of glands, one representing those of the
anthers, and the others those of the stigmas, in the sexual organs of
vegetables; which is spoken of at large in Phytologia, Sect. VII. and
in Zoonomia, Vol. I. Sect. XXXIX. 8. of the third edition, in octavo;
where it is likewise shown, that none of these parts which are
deposited beneath the cuticle of the tree, is in itself a complete
vegetable embryon, but that they form one by their reciprocal
conjunction.
So in the sexual reproduction of animals, certain parts separated from
the living organs, and floating in the blood, are arrested by the
sexual glands of the female, and others by those of the male. Of these
none are complete embryon animals, but form an embryon by their
reciprocal conjunction.
There hence appears to be an analogy between generation and nutrition,
as one is the production of new organization, and the other the
restoration of that which previously existed; and which may therefore
be supposed to require materials somewhat similar. Now the food taken
up by animal lacteals is previously prepared by the chemical process
of digestion in the stomach; but that which is taken up by vegetable
lacteals, is prepared by chemical dissolution of organic matter
beneath the surface of the earth. Thus the particles, which form
generated animal embryons, are prepared from dead organic matter by
the chemico-animal processes of sanguification and of secretion; while
those which form spontaneous microscopic animals or microscopic
vegetables are prepared by chemical dissolutions and new combinations
of organic matter in watery fluids with sufficient warmth.
It may be here added, that the production and properties of some kinds
of inanimate matter, are almost as difficult to comprehend as those of
the simplest degrees of animation. Thus the elastic gum, or
caoutchouc, and some fossile bitumens, when drawn out to a great
length, contract themselves by their elasticity, like an animal fibre
by stimulus. The laws of action of these, and all other elastic
bodies, are not yet understood; as the laws of the attraction of
cohesion, to produce these effects, must be very different from those
of general attraction, since the farther the particles of elastic
bodies are drawn from each other till they separate, the stronger they
seem to attract; and the nearer they are pressed together, the more
they seem to repel; as in bending a spring, or in extending a piece of
elastic gum; which is the reverse to what occurs in the attractions
of disunited bodies; and much wants further investigation. So the
spontaneous production of alcohol or of vinegar, by the vinous and
acetous fermentations, as well as the production of a mucus by
putrefaction which will contract when extended, seems almost as
difficult to understand as the spontaneous production of a fibre from
decomposing animal or vegetable substances, which will contract when
stimulated, and thus constitutes the primordium of life.
Some of the microscopic animals are said to remain dead for many days
or weeks, when the fluid in which they existed is dried up, and
quickly to recover life and motion by the fresh addition of water and
warmth. Thus the chaos redivivum of Linnaeus dwells in vinegar and in
bookbinders paste: it revives by water after having been dried for
years, and is both oviparous and viviparous; Syst. Nat. Thus the
vorticella or wheel animal, which is found in rain water that has
stood some days in leaden gutters, or in hollows of lead on the tops
of houses, or in the slime or sediment left by such water, though it
discovers no sign of life except when in the water, yet it is capable
of continuing alive for many months though kept in a dry state. In
this state it is of a globulous shape, exceeds not the bigness of a
grain of sand, and no signs of life appear; but being put into water,
in the space of half an hour a languid motion begins, the globule
turns itself about, lengthens itself by slow degrees, assumes the form
of a lively maggot, and most commonly in a few minutes afterwards puts
out its wheels, swimming vigorously through the water as if in search
of food; or else, fixing itself by the tail, works the wheels in such
a manner as to bring its food to its mouth; English Encyclopedia, Art.
Animalcule.
Thus some shell-snails in the cabinets of the curious have been kept
in a dry state for ten years or longer, and have revived on being
moistened with warmish water; Philos. Transact. So eggs and seeds
after many months torpor, are revived by warmth and moisture; hence it
may be concluded, that even the organic particles of dead animals may,
when exposed to a due degree of warmth and moisture, regain some
degree of vitality, since this is done by more complicate animal
organs in the instances above mentioned.
The hydra of Linnaeus, which dwells in the rivers of Europe under
aquatic plants, has been observed by the curious of the present time,
to revive after it has been dried, to be restored after being
mutilated, to multiply by being divided, to be propagated from small
portions, to live after being inverted; all which would be best
explained by the doctrine of spontaneous reproduction from organic
particles not yet completely decomposed.
To this should be added, that these microscopic animals are found in
all solutions of vegetable or animal matter in water; as black pepper
steeped in water, hay suffered to become putrid in water, and the
water of dunghills, afford animalcules in astonishing numbers. See Mr.
Ellis's curious account of Animalcules produced from an infusion of
Potatoes and Hempseed; Philos. Transact. Vol. LIX. from all which it
would appear, that organic particles of dead vegetables and animals
during their usual chemical changes into putridity or acidity, do not
lose all their organization or vitality, but retain so much of it as
to unite with the parts of living animals in the process of nutrition,
or unite and produce new complicate animals by secretion as in
generation, or produce very simple microscopic animals or microscopic
vegetables, by their new combinations in warmth and moisture.
And finally, that these microscopic organic bodies are multiplied and
enlarged by solitary reproduction without sexual intercourse till they
acquire greater perfection or new properties. Lewenhoek observed in
rain-water which had stood a few days, the smallest scarcely visible
microscopic animalcules, and in a few more days he observed others
eight times as large; English Encyclop. Art. Animalcule.
_Conclusion._
There is therefore no absurdity in believing that the most simple
animals and vegetables may be produced by the congress of the parts of
decomposing organic matter, without what can properly be termed
generation, as the genus did not previously exist; which accounts for
the endless varieties, as well as for the immense numbers of
microscopic animals.
The green vegetable matter of Dr. Priestley, which is universally
produced in stagnant water, and the mucor, or mouldiness, which is
seen on the surface of all putrid vegetable and animal matter, have
probably no parents, but a spontaneous origin from the congress of the
decomposing organic particles, and afterwards propagate themselves.
Some other fungi, as those growing in close wine-vaults, or others
which arise from decaying trees, or rotten timber, may perhaps be
owing to a similar spontaneous production, and not previously exist as
perfect organic beings in the juices of the wood, as some have
supposed. In the same manner it would seem, that the common esculent
mushroom is produced from horse dung at any time and in any place, as
is the common practice of many gardeners; Kennedy on Gardening.
_Appendix._
The knowledge of microscopic animals is still in its infancy: those
already known are arranged by Mr. Muller into the following classes;
but it is probable, that many more classes, as well as innumerable
individuals, may be discovered by improvements of the microscope, as
Mr. Herschell has discovered so many thousand stars, which were before
invisible, by improvements of the telescope.
Mr. Muller's classes consist of
I. _Such as have no External Organs._
1. Monas: Punctiformis. A mere point.
2. Proteus: Mutabilis. Mutable.
3. Volvox: Sphaericum. Spherical.
4. Enchelis: Cylindracea. Cylindrical.
5. Vibrio: Elongatum. Long.
*Membranaceous.
6. Cyclidium: Ovale. Oval.
7. Paramecium: Oblongum. Oblong.
8. Kolpoda: Sinuatum. Sinuous.
9. Gonium: Angulatum. With angles.
10. Bursaria. Hollow like a purse.
II. _Those that have External Organs._
*Naked, or not enclosed in a shell.
1. Cercaria: Caudatum. With a tail.
2. Trichoda: Crinitum. Hairy.
3. Kerona: Corniculatum. With horns.
4. Himantopus: Cirratum. Cirrated.
5. Leucophra: Ciliatum undique. Every part ciliated.
6. Vorticella: Ciliatum apice. The apex ciliated.
*Covered with a shell.
7. Brachionus: Ciliatum apice. The apex ciliated.
1. These animalcules are discovered in two or three days in all
decompositions of organic matter, whether vegetable or animal, in
moderate degrees of warmth with sufficient moisture.
2. They appear to enlarge in a few days, and some to change their
form; which are probably converted from more simple into more
complicate animalcules by repeated reproductions. See Note VIII.
3. In their early state they seem to multiply by viviparous solitary
reproduction, either by external division, as the smaller ones, or by
an internal progeny, as the eels in paste or vinegar; and lastly, in
their more mature state, the larger ones are said to appear to have
sexual connexion. Engl. Encyclop.
4. Those animalcules discovered in pustules of the itch, in the feces
of dysenteric patients, and in semine masculino, I suppose to be
produced by the stagnation and incipient decomposition of those
materials in their receptacles, and not to exist in the living blood
or recent secretions; as none, I believe, have been discovered in
blood when first drawn from the arm, or in fluids newly secreted from
the glands, which have not previously stagnated in their reservoirs.
5. They are observed to move in all directions with ease and rapidity,
and to avoid obstacles, and not to interfere with each other in their
motions. When the water is in part evaporated, they are seen to flock
towards the remaining part, and show great agitation. They sustain a
great degree of cold, as some insects, and perish in much the same
degree of heat as destroys insects; all which evince that they are
living animals.
And it is probable, that other or similar animalcules may be produced
in the air, or near the surface of the earth, but it is not so easy to
view them as in water; which as it is transparent, the creatures
produced in it can easily be observed by applying a drop to a
microscope. I hope that microscopic researches may again excite the
attention of philosophers, as unforeseen advantages may probably be
derived from them, like the discovery of a new world.
ADDITIONAL NOTES. II.
THE FACULTIES OF THE SENSORIUM.
Next the long nerves unite their silver train,
And young Sensation permeates the brain.
CANT. I. l. 250.
I. The fibres, which constitute the muscles and organs of sense,
possess a power of contraction. The circumstances attending the
exertion of this power of contraction constitute the laws of animal
motion, as the circumstances attending the exertion of the power of
attraction constitute the laws of motion of inanimate matter.
II. The spirit of animation is the immediate cause of the contraction
of animal fibres, it resides in the brain and nerves, and is liable to
general or partial diminution or accumulation.
III. The stimulus of bodies external to the moving organ is the remote
cause of the original contractions of animal fibres.
IV. A certain quantity of stimulus produces irritation, which is an
exertion of the spirit of animation exciting the fibres into
contraction.
V. A certain quantity of contraction of animal fibres, if it be
perceived at all, produces pleasure; a greater or less quantity of
contraction, if it be perceived at all, produces pain; these
constitute sensation.
VI. A certain quantity of sensation produces desire or aversion; these
constitute volition.
VII. All animal motions which have occurred at the same time, or in
immediate succession, become so connected, that when one of them is
reproduced, the other has a tendency to accompany or succeed it. When
fibrous contractions succeed or accompany other fibrous contractions,
the connexion is termed association; when fibrous contractions succeed
sensorial motions, the connexion is termed causation; when fibrous and
sensorial motions reciprocally introduce each other, it is termed
catenation of animal motions.
VIII. These four faculties of the sensorium during their inactive
state are termed irritability, sensibility, voluntarily, and
associability; in their active state they are termed as above
irritation, sensation, volition, association.
Irritation is an exertion or change of some extreme part of the
sensorium residing in the muscles or organs of sense, in consequence
of the appulses of external bodies.
Sensation is an exertion or change of the central parts of the
sensorium, or of the whole of it, beginning at some of those extreme
parts of it, which reside in the muscles or organs of sense.
Volition is an exertion or change of the central parts of the
sensorium, or of the whole of it, terminating in some of those extreme
parts of it, which reside in the muscles or organs of sense.
Association is an exertion or change of some extreme part of the
sensorium residing in the muscles or organs of sense, in consequence
of some antecedent or attendant fibrous contractions; see Zoonomia,
Vol. I.
The word sensorium is used to express not only the medullary part of
the brain, spinal marrow, nerves, organs of sense and muscles, but
also at the same time that living principle, or spirit of animation,
which resides throughout the body, without being cognizable to our
senses except by its effects.
ADDITIONAL NOTES. III.
Next when imprison'd fires in central caves
Burst the firm earth, and drank the headlong waves.
CANTO I. l. 302.
The great and repeated explosions of volcanoes are shown by Mr.
Mitchell in the Philosoph. Transact. to arise from their communication
with the sea, or with rivers, or inundations; and that after a chink
or crack is made, the water rushing into an immense burning cavern,
and falling on boiling lava, is instantly expanded into steam, and
produces irresistible explosions.
As the first volcanic fires had no previous vent, and were probably
more central, and larger in quantity, before they burst the crust of
the earth then intire, and as the sea covered the whole, it must
rapidly sink down into every opening chink; whence these primeval
earthquakes were of much greater extent, and of much greater force,
than those which occur in the present era.
It should be added, that there may be other elastic vapours produced
by great heat from whatever will evaporate, as mercury, and even
diamonds; which may be more elastic, and consequently exert greater
force than the steam of water even though heated red hot. Which may
thence exert a sufficient power to raise islands and continents, and
even to throw the moon from the earth.
If the moon be supposed to have been thus thrown out of the great
cavity which now contains the South Sea, the immense quantity of water
flowing in from the primeval ocean, which then covered the earth,
would much contribute to leave the continents and islands, which might
be raised at the same time above the surface of the water. In later
days there are accounts of large stones falling from the sky, which
may have been thus thrown by explosion from some distant earthquake,
without sufficient force to cause them to circulate round the earth,
and thus produce numerous small moons or satellites.
Mr. Mitchell observes, that the agitations of the earth from the great
earthquake at Lisbon were felt in this country about the same time
after the shock, as sound would have taken in passing from Lisbon
hither; and thence ascribes these agitations to the vibrations of the
solid earth, and not to subterraneous caverns of communication;
Philos. Transact. But from the existence of warm springs at Bath and
Buxton, there must certainly be unceasing subterraneous fires at some
great depth beneath those parts of this island; see on this subject
Botanic Garden, Vol. II. Canto IV. l. 79, note. For an account of the
noxious vapours emitted from volcanoes, see Botanic Garden, Vol. II.
Cant. IV. l. 328, note. For the milder effects of central fires, see
Botanic Garden, Vol. I. Cant. I. l. 139, and Additional Note VI.
ADDITIONAL NOTES. IV.
So from deep lakes the dread musquito springs,
Drinks the soft breeze, and dries his tender wings.
CANTO I. l. 327.
The gnat, or musquito, culex pipiens. The larva of this insect lives
chiefly in water, and the pupa moves with great agility. It is fished
for by ducks; and, when it becomes a fly, is the food of the young of
partridges, quails, sparrows, swallows, and other small birds. The
females wound us, and leave a red point; and in India their bite is
more venomous. The male has its antennae and feelers feathered, and
seldom bites or sucks blood; Lin. Syst. Nat.
It may be driven away by smoke, especially by that from inula
helenium, elecampane; and by that of cannabis, hemp. Kalm. It is said
that a light in a chamber will prevent their attack on sleeping
persons.
The gnats of this country are produced in greater numbers in some
years than others, and are then seen in swarms for many evenings near
the lakes or rivers whence they arise; and, I suppose, emigrate to
upland situations, where fewer of them are produced. About thirty
years ago such a swarm was observed by Mr. Whitehurst for a day or two
about the lofty tower of Derby church, as to give a suspicion of the
fabric being on fire.
Many other kinds of flies have their origin in the water, as perhaps
the whole class of neuroptera. Thus the libellula, dragon fly: the
larva of which hurries amid the water, and is the cruel crocodile of
aquatic insects. After they become flies, they prey principally on the
class of insects termed lepidoptera, and diptera of Linneus. The
ephemera is another of this order, which rises from the lakes in such
quantities in some countries, that the rustics have carried cart-loads
of them to manure their corn lands; the larva swims in the water: in
its fly-state the pleasures of life are of short duration, as its
marriage, production of its progeny, and funeral, are often
celebrated in one day. The phryganea is another fly of this order; the
larva lies concealed under the water in moveable cylindrical tubes of
their own making. In the fly-state they institute evening dances in
the air in swarms, and are fished for by the swallows.
Many other flies, who do not leave their eggs in water, contrive to
lay them in moist places, as the oestros bovis; the larvae of which
exist in the bodies of cattle, where they are nourished during the
winter, and are occasionally extracted by a bird of the crow-kind
called buphaga. These larvae are also found in the stomachs of horses,
whom they sometimes destroy; another species of them adhere to the
anus of horses, and creep into the lowest bowel, and are called botts;
and another species enters the frontal sinus of sheep, occasioning a
vertigo called the turn. The musca pendula lives in stagnant water;
the larva is suspended by a thread-form respiratory tube; of the musca
chamaeleon, the larva lives in fountains, and the fly occasionally
walks upon the water. The musca vomitoria is produced in carcases;
three of these flies consume the dead body of a horse as soon as a
lion. Lin. Syst. Nat.
ADDITIONAL NOTE. V.
AMPHIBIOUS ANIMALS.
So still the Diodons, amphibious tribe,
With twofold lungs the sea and air imbibe.
CANT. I. l. 331.
D. D. Garden dissected the amphibious creature called diodon by
Linneus, and was amazed to find that it possessed both external gills
and internal lungs, which he described and prepared and sent to
Linneus; who thence put this animal into the order nantes of his class
amphibia. He adds also, in his account of polymorpha before the class
amphibia, that some of this class breathe by lungs only, and others by
both lungs and gills.
Some amphibious quadrupeds, as the beaver, water rat, and otter, are
said to have the foramen ovale of the heart open, which communicates
from one cavity of it to the other; and that, during their continuance
under water, the blood can thus for a time circulate without passing
through the lungs; but as it cannot by these means acquire oxygen
either from the air or water, these creatures find it frequently
necessary to rise to the surface to respire. As this foramen ovale is
always open in the foetus of quadrupeds, till after its birth that it
begins to respire, it has been proposed by some to keep young puppies
three or four times a day for a minute or two under warm water to
prevent this communication from one cavity of the heart to the other
from growing up; whence it has been thought such dogs might become
amphibious. It is also believed that this circumstance has existed in
some divers for pearl; whose children are said to have been thus kept
under water in their early infancy to enable them afterwards to
succeed in their employment.
But the most frequent distinction of the amphibious animals, that live
much in the water, is, that their heart consists but of one cell; and
as they are pale creatures with but little blood, and that colder and
darker coloured, as frogs and lizards, they require less oxygen than
the warmer animals with a greater quantity and more scarlet blood; and
thence, though they have only lungs, they can stay long under water
without great inconvenience; but are all of them, like frogs, and
crocodiles, and whales, necessitated frequently to rise above the
surface for air.
In this circumstance of their possessing a one-celled heart, and
colder and darker blood, they approach to the state of fish; which
thus appear not to acquire so much oxygen by their gills from the
water as terrestrial animals do by their lungs from the atmosphere;
whence it may be concluded that the gills of fish do not decompose the
water which passes through them, and which contains so much more
oxygen than the air, but that they only procure a small quantity of
oxygen from the air which is diffused in the water; which also is
further confirmed by an experiment with the air-pump, as fish soon die
when put in a glass of water into the exhausted receiver, which they
would not do if their gills had power to decompose the water and
obtain the oxygen from it.
The lamprey, petromyzon, is put by Linneus amongst the nantes, which
are defined to possess both gills and lungs. It has seven spiracula,
or breathing holes, on each side of the neck, and by its more perfect
lungs approaches to the serpent kind; Syst. Nat. The means by which it
adheres to stones, even in rapid streams, is probably owing to a
partial vacuum made by its respiring organs like sucking, and may be
compared to the ingenious method by which boys are seen to lift large
stones in the street, by applying to them a piece of strong moist
leather with a string through the centre of it; which, when it is
forcibly drawn upwards, produces a partial vacuum under it, and thus
the stone is supported by the pressure of the atmosphere.
The leech, hirudo, and the remora, echeneis, adhere strongly to
objects probably by a similar method. I once saw ten or twelve leeches
adhere to each foot of an old horse a little above his hoofs, who was
grazing in a morass, and which did not lose their hold when he moved
about. The bare-legged travellers in Ceylon are said to be much
infested by leeches; and the sea-leech, hirudo muricata, is said to
adhere to fish, and the remora is said to adhere to ships in such
numbers as to retard their progress.
The respiratory organ of the whale, I suppose, is pulmonary in part,
as he is obliged to come frequently to the surface, whence he can be
pursued after he is struck with the harpoon; and may nevertheless be
in part like the gills of other fish, as he seems to draw in water
when he is below the surface, and emits it again when he rises above
it.
ADDITIONAL NOTE. VI.
HIEROGLYPHIC CHARACTERS.
So erst as Egypt's rude designs explain.
CANTO I. l. 351.
The outlines of animal bodies, which gave names to the constellations,
as well as the characters used in chemistry for the metals, and in
astronomy for the planets, were originally hieroglyphic figures, used
by the magi of Egypt before the invention of letters, to record their
discoveries in those sciences.
Other hieroglyphic figures seem to have been designed to perpetuate
the events of history, the discoveries in other arts, and the opinions
of those ancient philosophers on other subjects. Thus their figures of
Venus for beauty, Minerva for wisdom, Mars and Bellona for war,
Hercules for strength, and many others, became afterwards the deities
of Greece and Rome; and together with the figures of Time, Death, and
Fame, constitute the language of the painters to this day.
From the similarity of the characters which designate the metals in
chemistry, and the planets in astronomy, it may be concluded that
these parts of science were then believed to be connected; whence
astrology seems to have been a very early superstition. These, so far,
constitute an universal visible language in those sciences.
So the glory, or halo, round the head is a part of the universal
language of the eye, designating a holy person; wings on the shoulders
denote a good angel; and a tail and hoof denote the figure of an evil
demon; to which may be added the cap of liberty and the tiara of
popedom. It is to be wished that many other universal characters could
be introduced into practice, which might either constitute a more
comprehensive language for painters, or for other arts; as those of
ciphers and signs have done for arithmetic and algebra, and crotchets
for music, and the alphabets for articulate sounds; so a zigzag line
made on white paper by a black-lead pencil, which communicates with
the surface of the mercury in the barometer, as the paper itself is
made constantly to move laterally by a clock, and daily to descend
through the space necessary, has ingeniously produced a most accurate
visible account of the rise and fall of the mercury in the barometer
every hour in the year.
Mr. Grey's Memoria Technica was designed as an artificial language to
remember numbers, as of the eras, or dates of history. This was done
by substituting one consonant and one vowel for each figure of the ten
cyphers used in arithmetic, and by composing words of these letters;
which words Mr. Grey makes into hexameter verses, and produces an
audible jargon, which is to be committed to memory, and occasionally
analysed into numbers when required. An ingenious French botanist,
Monsieur Bergeret, has proposed to apply this idea of Mr. Grey to a
botanical nomenclature, by making the name of each plant to consist of
letters, which, when analysed, were to signify the number of the
class, order, genus, and species, with a description also of some
particular part of the plant, which was designed to be both an audible
and visible language.
Bishop Wilkins in his elaborate "Essay towards a Real Character and a
Philosophical Language," has endeavoured to produce, with the greatest
simplicity, and accuracy, and conciseness, an universal language both
to be written and spoken, for the purpose of the communication of all
our ideas with greater exactness and less labour than is done in
common languages, as they are now spoken and written. But we have to
lament that the progress of general science is yet too limited both
for his purpose, and for that even of a nomenclature for botany; and
that the science of grammar, and even the number and manner of the
pronunciation of the letters of the alphabet, are not yet determined
with such accuracy as would be necessary to constitute Bishop
Wilkins's grand design of an universal language, which might
facilitate the acquirement of knowledge, and thus add to the power and
happiness of mankind.
ADDITIONAL NOTE. VII.
OLD AGE AND DEATH.
The age-worn fibres goaded to contract
By repetition palsied, cease to act.
CANTO II. l. 4
I. _Effects of Age._
The immediate cause of the infirmities of age, or of the progress of
life to death, has not yet been well ascertained. The answer to the
question, why animals become feeble and diseased after a time, though
nourished with the same food which increased their growth from
infancy, and afterwards supported them for many years in unimpaired
health and strength, must be sought for from the laws of animal
excitability, which, though at first increased, is afterwards
diminished by frequent repetitions of its adapted stimulus, and at
length ceases to obey it.
1. There are four kinds of stimulus which induce the fibres to
contract, which constitute the muscles or the organs of sense; as,
first, The application of external bodies, which excites into action
the sensorial power of irritation; 2dly, Pleasure and pain, which
excite into action the sensorial power of sensation; 3dly, Desire and
aversion, which excite into action the power of volition; and lastly,
The fibrous contractions, which precede association, which is another
sensorial power; see Zoonomia, Vol. I. Sect. II. 13.
Many of the motions of the organic system, which are necessary to
life, are excited by more than one of these stimuli at the same time,
and some of them occasionally by them all. Thus respiration is
generally caused by the stimulus of blood in the lungs, or by the
sensation of the want of oxygen; but is also occasionally voluntary.
The actions of the heart also, though generally owing to the stimulus
of the blood, are also inflamed by the association of its motions with
those of the stomach, whence sometimes arises an inequality of the
pulse, and with other parts of the system, as with the capillaries,
whence heat of the skin in fevers with a feeble pulse, see Zoonomia.
They are also occasionally influenced by sensation, as is seen in the
paleness occasioned by fear, or the blush of shame and anger; and
lastly the motions of the heart are sometimes assisted by volition;
thus in those who are much weakened by fevers, the pulse is liable to
stop during their sleep, and to induce great distress; which is owing
at that time to the total suspension of voluntary power; the same
occurs during sleep in some asthmatic patients.
2. The debility of approaching age appears to be induced by the
inactivity of many parts of the system, or their disobedience to their
usual kinds and quantities of stimulus: thus the pallid appearance of
the skin of old age is owing to the inactivity of the heart, which
ceases to obey the irritation caused by the stimulus of the blood, or
its association with other moving organs with its former energy;
whence the capillary arteries are not sufficiently distended in their
diastole, and consequently contract by their elasticity, so as to
close the canal, and their sides gradually coalesce. Of these, those
which are most distant from the heart, and of the smallest diameters,
will soonest close, and become impervious; hence the hard pulse of
aged patients is occasioned by the coalescence of the sides of the
vasa vasorum, or capillary arteries of the coats of the other
arteries.
The veins of elderly people become turgid or distended with blood, and
stand prominent on the skin; for as these do not possess the
elasticity of the arteries, they become distended with accumulation of
blood; when the heart by its lessened excitability does not contract
sufficiently forcibly, or frequently, to receive, as fast as usual,
the returning blood; and their apparent prominence on the skin is
occasioned by the deficient secretion of fat or mucus in the cellular
membrane; and also to the contraction and coalescence and consequent
less bulk of many capillary arteries.
3. Not only the muscular fibres lose their degree of excitability from
age, as in the above examples; and as may be observed in the tremulous
hands and feeble step of elderly persons; but the organs of sense
become less excitable by the stimulus of external objects; whence the
sight and hearing become defective; the stimulus of the sensorial
power of sensation also less affects the aged, who grieve less for the
loss of friends or for other disappointments; it should nevertheless
be observed, that when the sensorial power of irritation is much
exhausted, or its production much diminished; the sensorial power of
sensation appears for a time to be increased; as in intoxication there
exists a kind of delirium and quick flow of ideas, and yet the person
becomes so weak as to totter as he walks; but this delirium is owing
to the defect of voluntary power to correct the streams of ideas by
intuitive analogy, as in dreams: see Zoonomia: and thus also those who
are enfeebled by habits of much vinous potation, or even by age alone,
are liable to weep at shaking hands with a friend, whom they have not
lately seen; which is owing to defect of voluntary power to correct
their trains of ideas caused by sensation, and not to the increased
quantity of sensation, as I formerly supposed.
The same want of voluntary power to keep the trains of sensitive ideas
consistent, and to compare them by intuitive analogy with the order of
nature, is the occasion of the starting at the clapping to of a door,
or the fall of a key, which occasions violent surprise with fear and
sometimes convulsions, in very feeble hysterical patients, and is not
owing I believe (as I formerly supposed) to increased sensation; as
they are less sensible to small stimuli than when in health.
Old people are less able also to perform the voluntary exertions of
exercise or of reasoning, and lastly the association of their ideas
becomes more imperfect, as they are forgetful of the names of persons
and places; the associations of which are less permanent, than those
of the other words of a language, which are more frequently repeated.
4. This disobedience of the fibres of age to their usual stimuli, has
generally been ascribed to repetition or habit, as those who live near
a large clock, or a mill, or a waterfall, soon cease to attend to the
perpetual noise of it in the day, and sleep dining the night
undisturbed. Thus all medicines, if repeated too frequently, gradually
lose their effect; as wine and opium cease to intoxicate: some
disagreeable tastes as tobacco, by frequent repetition cease to be
disagreeable; grief and pain gradually diminish and at length cease
altogether; and hence life itself becomes tolerable.
This diminished power of contraction of the fibres of the muscles or
organs of sense, which constitutes permanent debility or old age, may
arise from a deficient secretion of sensorial power in the brain, as
well as from the disobedience of the muscles and organs of sense to
their usual stimuli; but this less production of sensorial power must
depend on the inactivity of the glands, which compose the brain, and
are believed to separate it perpetually from the blood; and is thence
owing to a similar cause with the inaction of the fibres of the other
parts of the system.
It is finally easy to understand how the fibres may cease to act by
the usual quantity of stimulus after having been previously exposed to
a greater quantity of stimulus, or to one too long continued; because
the expenditure of sensorial power has then been greater than its
production; but it is not easy to explain why the repetition of
fibrous contractions, which during the meridian of life did not expend
the sensorial power faster than it was produced; or only in such a
degree as was daily restored by rest and sleep, should at length in
the advance of life expend too much of it; or otherwise, that less of
it should be produced in the brain; or reside in the nerves; lastly
that the fibres should become less excitable by the usual quantity of
it.
5. But these facts would seem to show, that all parts of the system
are not changed as we advance in life, as some have supposed; as in
that case it might have preserved for ever its excitability; and it
might then perhaps have been easier for nature to have continued her
animals and vegetables for ever in their mature state, than
perpetually by a complicate apparatus to have produced new ones, and
suffer the old ones to perish; for a further account of stimulus and
the consequent animal exertion, see Zoonomia, Vol. I. Sect. 12.
II. _Means of preventing old age._
The means of preventing the approach of age must therefore consist in
preventing the inexcitability of the fibres, or the diminution of the
production of sensorial power.
1. As animal motion cannot be performed without the fluid matter of
heat, in which all things are immersed, and without a sufficient
quantity of moisture to prevent rigidity: nothing seems so well
adapted to both these purposes as the use of the warm bath; and
especially in those, who become thin or emaciated with age, and who
have a hard and dry skin, with hardness of the coat of the arteries;
which feels under the finger like a cord; the patient should sit in
warm water for half an hour every day, or alternate days, or twice a
week; the heat should be about ninety-eight degrees on Fahrenheit's
scale, or of such a warmth, as may be most agreeable to his sensation;
but on leaving the bath he should always be kept so cool, whether he
goes into bed, or continues up, as not sensibly to perspire.
There is a popular prejudice, that the warm bath relaxes people, and
that the cold bath braces them; which are mechanical terms belonging
to drums and fiddle-strings, but not applicable except metaphorically
to animal bodies, and then commonly mean weakness and strength: during
the continuance in the bath the patient does not lose weight, unless
he goes in after a full meal, but generally weighs heavier as the
absorption is greater than the perspiration; but if he suffers himself
to sweat on his leaving the bath, he will undoubtedly be weakened by
the increased action of the system, and its exhaustion: the same
occurs to those who are heated by exercise, or by wine, or spice, but
not during their continuance in the warm bath: whence we may conclude,
that the warm bath is the most harmless of all those stimuli, which
are greater than our natural habits have accustomed us to; and that it
particularly counteracts the approach of old age in emaciated people
with dry skins.
It may be here observed in favour of bathing, that some fish are
believed to continue to a great age, and continually to enlarge in
size, as they advance in life; and that long after their state of
puberty. I have seen perch full of spawn, which were less than two
inches long; and it is known, that they will grow to six or eight
times that size; it is said, that the whales, which have been caught
of late years, are much less in size than those, which were caught,
when first the whale-fishery was established; as the large ones, which
were supposed to have been some hundred years old, are believed to be
already destroyed.
All cold-blooded amphibious animals more slowly waste their sensorial
power; as they are accustomed to less stimulus from their respiring
less oxygen; and their movements in water are slower than those of
aerial animals from the greater resistance of the element. There
besides seems to be no obstacle to the growth of aquatic animals; as
by means of the air-bladder, they can make their specific gravity the
same as that of the water in which they swim. And the moisture of the
element seems well adapted to counteract the rigidity of their fibres;
and as their exertions in locomotion, and the pressure of some parts
on others, are so much less than in the bodies of land animals.
2. But as all excessive stimuli exhaust the sensorial power, and
render the system less excitable for a time till the quantity of
sensorial power is restored by sleep, or by the diminution or absence
of stimulus; which is seen by the weakness of inebriates for a day at
least after intoxication. And as the frequent repetition of this great
and unnatural stimulus of fermented liquors produces a permanent
debility, or disobedience of the system to the usual and natural kinds
and quantities of stimulus, as occurs in those who have long been
addicted to the ingurgitation of fermented liquors.
And as, secondly, the too great deficiency of the quantity of natural
stimuli, as of food, and warmth, or of fresh air, produces also
diseases; as is often seen in the children of the poor in large towns,
who become scrofulous from want of due nourishment, and from cold,
damp, unairy lodgings.
The great and principal means to prevent the approach of old age and
death, must consist in the due management of the quantity of every
kind of stimulus, but particularly of that from objects external to
the moving organ; which may excite into action too great or too small
a quantity of the sensorial power of irritation, which principally
actuates the vital organs. Whence the use of much wine, or opium, or
spice, or of much salt, by their unnatural stimulus induces consequent
debility, and shortens life, on the one hand, by the exhaustion of
sensorial power; so on the other hand, the want of heat, food, and
fresh air, induces debility from defect of stimulus, and a consequent
accumulation of sensorial power, and a general debility of the system.
Whence arise the pains of cold and hunger, and those which are called
nervous; and which are the cause of hysteric, epileptic, and perhaps
of asthmatic paroxysms, and of the cold fits of fever.
3. Though all excesses of increase and decrease of stimulus should be
avoided, yet a certain variation of stimulus seems to prolong the
excitability of the system; as during any diminution of the usual
quantity of stimulus, an accumulation of sensorial power is produced;
and in consequence the excitability, which was lessened by the action
of habitual stimulus, becomes restored. Thus those, who are uniformly
habituated to much artificial heat, as in warm parlours in the winter
months, lose their irritability in some degree, and become feeble like
hot-house plants; but by frequently going for a time into the cold
air, the sensorial power of irritability is accumulated and they
become stronger.
Whence it may be deduced, that the variations of the cold and heat of
this climate contribute to strengthen its inhabitants, who are more
active and vigorous, and live longer, than those of either much warmer
or much colder latitudes.
This accumulation of sensorial power from diminution of stimulus any
one may observe, who in severe weather may sit by the fire-side till
he is chill and uneasy with the sensation of cold; but if he walks
into the frosty air for a few minutes, an accumulation of sensorial
power is produced by diminution of the stimulus of heat, and on his
returning into the room where he was chill before, his whole skin will
now glow with warmth.
Hence it may be concluded, that the variations of the quantity of
stimuli within certain limits contribute to our health; and that those
houses which are kept too uniformly warm, are less wholesome than
where the inhabitants are occasionally exposed to cold air in passing
from one room to another.
Nevertheless to those weak habits with pale skins and large pupils of
the eyes, whose degree of irritability is less than health requires,
as in scrofulous, hysterical, and some consumptive constitutions, a
climate warmer than our own may be of service, as a greater stimulus
of heat may be wanted to excite their less irritability. And also a
more uniform quantity of heat may be serviceable to consumptive
patients than is met with in this country, as the lungs cannot be
clothed like the external skin, and are therefore subject to greater
extremes of heat and cold in passing in winter from a warm room into
the frosty air.
4. It should nevertheless be observed, that there is one kind of
stimulus, which though it be employed in quantity beyond its usual
state, seems to increase the production of sensorial power beyond the
expenditure of it (unless its excess is great indeed) and thence to
give permanent strength and energy to the system; I mean that of
volition. This appears not only from the temporary strength of angry
or insane people, but because insanity even cures some diseases of
debility, as I have seen in dropsy, and in some fevers; but it is also
observable, that many who have exerted much voluntary effort during
their whole lives, have continued active to great age. This however
may be conceived to arise from these great exertions being performed
principally by the organs of sense, that is by exciting and comparing
ideas; as in those who have invented sciences, or have governed
nations, and which did not therefore exhaust the sensorial power of
those organs which are necessary to life, but perhaps rather prevented
them from being sooner impaired, their sensorial power not having been
so frequently exhausted by great activity, for very violent exercise
of the body, long continued, forwards old age; as is seen in
post-horses that are cruelly treated, and in many of the poor, who
with difficulty support their families by incessant labour.
III. _Theory of the Approach of Age._
The critical reader is perhaps by this time become so far interested
in this subject as to excuse a more prolix elucidation of it.
In early life the repetition of animal actions occasions them to be
performed with greater facility, whether those repetitions are
produced by volition, sensation, or irritation; because they soon
become associated together, if as much sensorial power is produced
between every reiteration of action, as is expended by it.
But if a stimulus be repeated at uniform intervals of time, the
action, whether of our muscles or organs of sense, is performed with
still greater facility and energy; because the sensorial power of
association mentioned above, is combined with the sensorial power of
irritation, and forms part of the diurnal chain of animal motions;
that is, in common language, the acquired habit assists the power of
the stimulus; see Zoonomia, Vol. I. Sect. XXII. 2. and Sect. XII. 3.
3.
On this circumstance depends the easy motions of the fingers in
performing music, and of the feet and arms in dancing and fencing, and
of the hands in the use of tools in mechanic arts, as well as all the
vital motions which animate and nourish organic bodies.
On the contrary, many animal motions by perpetual repetition are
performed with less energy; as those who live near a waterfall, or a
smith's forge, after a time, cease to hear them. And in those
infectious diseases which are attended with fever, as the small-pox
and measles, violent motions of the system are excited, which at
length cease, and cannot again be produced by application of the same
stimulating material; as when those are inoculated for the small-pox,
who have before undergone that malady. Hence the repetition, which
occasions animal actions for a time to be performed with greater
energy, occasions them at length to become feeble, or to cease
entirely.
To explain this difficult problem we must more minutely consider the
catenations of animal motions, as described in Zoonomia, Vol. I. Sect.
XVII. The vital motions, as suppose of the heart and arterial system,
commence from the irritation occasioned by the stimulus of the blood,
and then have this irritation assisted by the power of association; at
the same time an agreeable sensation is produced by the due actions of
the fibres, as in the secretions of the glands, which constitutes the
pleasure of existence; this agreeable sensation is intermixed between
every link of this diurnal chain of actions, and contributes to
produce it by what is termed animal causation. But there is also a
degree of the power of volition excited in consequence of this vital
pleasure, which is also intermixed between the links of the chain of
fibrous actions; and thus also contributes to its uniform easy and
perpetual production.
The effects of surprise and novelty must now be considered by the
patient reader, as they affect the catenations of action; and, I hope,
the curiosity of the subject will excuse the prolixity of this account
of it. When any violent stimulus breaks the passing current or
catenation of our ideas, surprise is produced, which is accompanied
with pain or pleasure, and consequent volition to examine the object
of it, as explained in Zoonomia, Vol. I. Sect. XVIII. 17, and which
never affects us in sleep. In our waking hours whenever an idea of
imagination occurs, which is incongruous to our former experience, we
feel another kind of surprise, and instantly dissever the train of
imagination by the power of volition, and compare the incongruous idea
with our previous knowledge of nature, and reject it by an act of
reasoning, of which we are unconscious, termed in Zoonomia, "Intuitive
Analogy," Vol. I Sect. XVII. 7.
The novelty of any idea may be considered as affecting us with another
kind of surprise, or incongruity, as it differs from the usual train
of our ideas, and forms a new link in this perpetual chain; which, as
it thus differs from the ordinary course of nature, we instantly
examine by the voluntary efforts of intuitive analogy; or by
reasoning, which we attend to; and compare it with the usual
appearances of nature.
These ideas which affect us with surprise, or incongruity, or novelty,
are attended with painful or pleasurable sensation; which we mentioned
before as intermixing with all catenations of animal actions, and
contributing to strengthen their perpetual and energetic production;
and also exciting in some degree the power of volition, which also
intermixes with the links of the chain of animal actions, and
contributes to produce it.
Now by frequent repetition the surprise, incongruity, or novelty
ceases; and, in consequence, the pleasure or pain which accompanied
it, and also the degree of volition which was excited by that
sensation of pain or pleasure; and thus the sensorial power of
sensation and of volition are subducted from the catenation of vital
actions, and they are in consequence produced much weaker, and at
length cease entirely. Whence we learn why contagious matters induce
their effects on the circulation but once; and why, in process of
time, the vital movements are performed with less energy, and at
length cease; whence the debilities of age, and consequent death.
ADDITIONAL NOTES. VIII.
REPRODUCTION.
But Reproduction with ethereal fires
New life rekindles, ere the first expires.
CANTO II. l. 13.
I. The reproduction or generation of living organized bodies, is the
great criterion or characteristic which distinguishes animation from
mechanism. Fluids may circulate in hydraulic machines, or simply move
in them, as mercury in the barometer or thermometer, but the power of
producing an embryon which shall gradually acquire similitude to its
parent, distinguishes artificial from natural organization.
The reproduction of plants and animals appears to be of two kinds,
solitary and sexual; the former occurs in the formation of the buds of
trees, and the bulbs of tulips; which for several successions generate
other buds, and other bulbs, nearly similar to the parent, but
constantly approaching to greater perfection, so as finally to produce
sexual organs, or flowers, and consequent seeds.
The same occurs in some inferior kinds of animals; as the aphises in
the spring and summer are viviparous for eight or nine generations,
which successively produce living descendants without sexual
intercourse, and are themselves, I suppose, without sex; at length in
the autumn they propagate males and females, which copulate and lay
eggs, which lie dormant during the winter, and are hatched by the
vernal sun; while the truffle, and perhaps mushrooms amongst
vegetables, and the polypus and taenia amongst insects, perpetually
propagate themselves by solitary reproduction, and have not yet
acquired male and female organs.
Philosophers have thought these viviparous aphides, and the taenia, and
volvox, to be females; and have supposed them to have been impregnated
long before their nativity within each other; so the taenia and volvox
still continue to produce their offspring without sexual intercourse.
One extremity of the taenia, is said by Linneus to grow old, whilst at
the other end new ones are generated proceeding to infinity like the
roots of grass. The volvox globator is transparent, and carries within
itself children and grandchildren to the fifth generation like the
aphides; so that the taenia produces children and grandchildren
longitudinally in a chain-like series, and the volvox propagates an
offspring included within itself to the fifth generation; Syst. Nat.
Many microscopic animals, and some larger ones, as the hydra or
polypus, are propagated by splitting or dividing; and some still
larger animals, as oysters, and perhaps eels, have not yet acquired
sexual organs, but produce a paternal progeny, which requires no
mother to supply it with a nidus, or with nutriment and oxygenation;
and, therefore, very accurately resemble the production of the buds of
trees, and the wires of some herbaceous plants, as of knot-grass and
of strawberries, and the bulbs of other plants, as of onions and
potatoes; which is further treated of in Phytologia, Sect. VII.
The manner in which I suspect the solitary reproduction of the buds of
trees to be effected, may also be applied to the solitary generation
of the insects mentioned above, and probably of many others, perhaps
of all the microscopic ones. It should be previously observed, that
many insects are hermaphrodite, possessing both male and female organs
of reproduction, as shell-snails and dew-worms; but that these are
seen reciprocally to copulate with each other, and are believed not to
be able to impregnate themselves; which belongs, therefore, to sexual
generation, and not to the solitary reproduction of which I am now
speaking.
As in the chemical production of any new combination of matter, two
kinds of particles appear to be necessary; one of which must possess
the power of attraction, and the other the aptitude to be attracted,
as a magnet and a piece of iron; so in vegetable or animal
combinations, whether for the purpose of nutrition or for
reproduction, there must exist also two kinds of organic matter; one
possessing the appetency to unite, and the other the propensity to be
united; (see Zoonomia, octavo edition, Sect. XXXIX. 8.) Hence in the
generation of the buds of trees, there are probably two kinds of
glands, which acquire from the vegetable blood, and deposite beneath
the cuticle of the tree two kinds of formative organic matter, which
unite and form parts of the new vegetable embryon; which again uniting
with other such organizations form the caudex, or the plumula, or the
radicle, of a new vegetable bud.
A similar mode of reproduction by the secretion of two kinds of
organic particles from the blood, and by depositing them either
internally as in the vernal and summer aphis or volvox, or externally
as in the polypus and taenia, probably obtains in those animals; which
are thence propagated by the father only, not requiring a cradle, or
nutriment, or oxygenation from a mother; and that the five
generations, said to be seen in the transparent volvox globator within
each other, are perhaps the successive progeny to be delivered at
different periods of time from the father, and erroneously supposed to
be mothers impregnated before their nativity.
II. Sexual as well as solitary reproduction appears to be effected by
two kinds of glands; one of which collects or secretes from the blood
formative organic particles with appetencies to unite, and the other
formative organic particles with propensities to be united. These
probably undergo some change by a kind of digestion in their
respective glands; but could not otherwise unite previously in the
mass of blood from its perpetual motion.
The first mode of sexual reproduction seems to have been by the
formation of males into hermaphrodites; that is, when the numerous
formative glands, which existed in the caudex of the bud of a tree, or
on the surface of a polypus, became so united as to form but two
glands; which might then be called male and female organs. But they
still collect and secrete their adapted particles from the same mass
of blood as in snails and dew-worms, but do not seem to be so placed
as to produce an embryon by the mixture of their secreted fluids, but
to require the mutual assistance of two hermaphrodites for that
purpose.
From this view-of the subject, it would appear that vegetables and
animals were at first propagated by solitary generation, and
afterwards by hermaphrodite sexual generation; because most vegetables
possess at this day both male and female organs in the same flower,
which Linneus has thence well called hermaphrodite flowers; and that
this hermaphrodite mode of reproduction still exists in many insects,
as in snails and worms; and, finally, because all the male quadrupeds,
as well as men, possess at this day some remains of the female
apparatus, as the breasts with nipples, which still at their nativity
are said to be replete with a kind of milk, and the nipples swell on
titillation.
Afterwards the sexes seem to have been formed in vegetables as in
flowers, in addition to the power of solitary reproduction by buds. So
in animals the aphis is propagated both by solitary reproduction as in
spring, or by sexual generation as in autumn; then the vegetable sexes
began to exist in separate plants, as in the classes monoecia and
dioecia, or both of them in the same plant also, as in the class
polygamia; but the larger and more perfect animals are now propagated
by sexual reproduction only, which seems to have been the
chef-d'oeuvre, or capital work of nature; as appears by the wonderful
transformations of leaf-eating caterpillars into honey-eating moths
and butterflies, apparently for the sole purpose of the formation of
sexual organs, as in the silk-worm, which takes no food after its
transformation, but propagates its species and dies.
III. _Recapitulation._
The microscopic productions of spontaneous vitality, and the next most
inferior kinds of vegetables and animals, propagate by solitary
generation only; as the buds and bulbs raised immediately from seeds,
the lycoperdon tuber, with probably many other fungi, and the polypus,
volvox, and taenia. Those of the next order propagate both by solitary
and sexual reproduction, as those buds and bulbs which produce flowers
as well as other buds or bulbs; and the aphis, and probably many other
insects. Whence it appears, that many of those vegetables and animals,
which are produced by solitary generation, gradually become more
perfect, and at length produce a sexual progeny.
A third order of organic nature consists of hermaphrodite vegetables
and animals, as in those flowers which have anthers and stigmas in the
same corol; and in many insects, as leeches, snails, and worms; and
perhaps all those reptiles which have no bones, according to the
observation of M. Poupart, who thinks, that the number of
hermaphrodite animals exceeds that of those which are divided into
sexes; Mem. de l'Acad. des Sciences. These hermaphrodite insects I
suspect _to_ be incapable of impregnating themselves for reasons
mentioned in Zoonomia, Sect. XXXIX. 6. 2.
And, lastly, the most perfect orders of animals are propagated by
sexual intercourse only; which, however, does not extend to
vegetables, as all those raised from seed produce some generations of
buds or bulbs, previous to their producing flowers, as occurs not only
in trees, but also in the annual plants. Thus three or four joints of
wheat grow upon each other, before that which produces a flower; which
joints are all separate plants growing over each other, like the buds
of trees, previous to the uppermost; though this happens in a few
months in annual plants, which requires as many years in the
successive buds of trees; as is further explained in Phytologia, Sect.
IX. 3. 1.
IV. _Conclusion._
Where climate is favourable, and salubrious food plentiful, there is
reason to believe, that the races of animals perpetually improve by
reproduction. The smallest microscopic animals become larger ones in a
short time, probably by successive reproductions, as is so distinctly
seen in the buds of seedling apple-trees, and in the bulbs of tulips
raised from seed; both which die annually, and leave behind them one
or many, which are more perfect than themselves, till they produce a
sexual progeny, or flowers. To which may be added, the rapid
improvement of our domesticated dogs, horses, rabbits, pigeons, which
improve in size, or in swiftness, or in the sagacity of the sense of
smell, or in colour, or other properties, by sexual reproduction.
The great Linneus having perceived the changes produced in the
vegetable world by sexual reproduction, has supposed that not more
than about sixty plants were at first created, and that all the others
have been formed by their solitary or sexual reproductions; and adds,
Suadent haec Creatoris leges a simplicibus ad composita; Gen. Plant.
preface to the natural orders, and Amenit. Acad. VI. 279. This mode
of reasoning may be extended to the most simple productions of
spontaneous vitality.
There is one curious circumstance of animal life analogous in some
degree to this wonderful power of reproduction; which is seen in the
propagation of some contagious diseases. Thus one grain of variolous
matter, inserted by inoculation, shall in about seven days stimulate
the system into unnatural action; which in about seven days more
produces ten thousand times the quantity of a similar material thrown
out on the skin in pustules!
The mystery of reproduction, which alone distinguishes organic life
from mechanic or chemic action, is yet wrapt in darkness. During the
decomposition of organic bodies, where there exists a due degree of
warmth with moisture, new microscopic animals of the most minute kind
are produced; and these possess the wonderful power of reproduction,
or of producing animals similar to themselves in their general
structure, but with frequent additional improvements; which the
preceding parent might in some measure have acquired by his habits of
life or accidental situation.
But it may appear too bold in the present state of our knowledge on
this subject, to suppose that all vegetables and animals now existing
were originally derived from the smallest microscopic ones, formed by
spontaneous vitality? and that they have by innumerable reproductions,
during innumerable centuries of time, gradually acquired the size,
strength, and excellence of form and faculties, which they now
possess? and that such amazing powers were originally impressed on
matter and spirit by the great Parent of Parents! Cause of Causes! Ens
Entium!
ADDITIONAL NOTES. IX.
STORGE.
And Heaven-born STORGE weaves the social chain.
CANTO II. l. 92.
The Greek word Storge is used for the affection of parents to
children; which was also visibly represented by the Stork or Pelican
feeding her young with blood taken from her own wounded bosom. A
number of Pelicans form a semicircle in shallow parts of the sea near
the coast, standing on their long legs; and thus including a shoal of
small fish, they gradually approach the shore; and seizing the fish as
they advance, receive them into a pouch under their throats; and
bringing them to land regurgitate them for the use of their young, or
for their future support. Adanson, Voyage to Senegal. In this country
the parent Pigeons both male and female swallow the grain or other
seeds, which they collect for their young, and bring it up mixed with
a kind of milk from their stomachs, with their bills inserted into the
mouths of the young doves. J. Hunter's works.
The affection of the parent to the young in experienced mothers may be
in part owing to their having been relieved by them from the burden of
their milk; but it is difficult to understand, how this affection
commences in those mothers of the bestial world, who have not
experienced this relief from the sucking of their offspring; and still
more so to understand how female birds were at first induced to
incubate their eggs for many weeks; and lastly how caterpillars, as of
the silk-worm, are induced to cover themselves with a well-woven house
of silk before their transformation.
These as well as many other animal facts, which are difficult to
account for, have been referred to an inexplicable instinct; which is
supposed to preclude any further investigation: but as animals seem to
have undergone great changes, as well as the inanimate parts of the
earth, and are probably still in a state of gradual improvement; it is
not unreasonable to conclude, that some of these actions both of large
animals and of insects, may have been acquired in a state preceding
their present one; and have been derived from the parents to their
offspring by imitation, or other kind of tradition; thus the eggs of
the crocodile are at this day hatched by the warmth of the sun in
Egypt; and the eggs of innumerable insects, and the spawn of fish, and
of frogs, in this climate are hatched by the vernal warmth: this might
be the case of birds in warm climates, in their early state of
existence; and experience might have taught them to incubate their
eggs, as they became more perfect animals, or removed themselves into
colder climates: thus the ostrich is said to sit upon its eggs only in
the night in warm situations, and both day and night in colder ones.
This love of the mother in quadrupeds to the offspring, whom she licks
and cleans, is so allied to the pleasure of the taste or palate, that
nature seems to have had a great escape in the parent quadruped not
devouring her offspring. Bitches, and cats, and sows, eat the
placenta; and if a dead offspring occurs, I am told, that also is
sometimes eaten, and yet the living offspring is spared; and by that
nice distinction the progenies of those animals are saved from
destruction!
"Certior factus sum a viro rebus antiquissimis docto, quod legitur in
Berosi operibus homines ante diluvium mulierum puerperarum placentam
edidisse, quasi cibum delicatum in epulis luxuriosis; et quod hoc
nefandissimo crimine movebatur Deus diluvio submergere terrarum
incolas." ANON.
It may be finally concluded, that this affection from the parent to
the progeny existed before animals were divided into sexes, and
produced the beginning of sympathetic society, the source of which may
perhaps be thus well accounted for; whenever the glandular system is
stimulated into greater natural action within certain limits, an
addition of pleasure is produced along with the increased secretion;
this pleasure arising from the activity of the system is supposed to
constitute the happiness of existence, in contradistinction to the
ennui or taedium vitae; as shown in Zoonomia, Sect. XXXIII. 1.
Hence the secretion of nutritious juices occasioned by the stimulus of
an embryon or egg in the womb gives pleasure to the parent for a
length of time; whence by association a similar pleasure may be
occasioned to the parent by seeing and touching the egg or fetus after
its birth; and in lactescent animals an additional pleasure is
produced by the new secretion of milk, as well as by its emission into
the sucking lips of the infant. This appears to be one of the great
secrets of Nature, one of those fine, almost invisible cords, which
have bound one animal to another.
The females of lactiferous animals have thus a passion or inlet of
pleasure in their systems more than the males, from their power of
giving suck to their offspring; the want of the object of this
passion, either owing to the death of the progeny, or to the unnatural
fashion of their situation in life, not only deprives them of this
innocent and virtuous source of pleasure; but has occasioned diseases,
which have been fatal to many of them.
ADDITIONAL NOTES. X.
EVE FROM ADAM'S RIB.
Form'd a new sex, the mother of mankind.
CANTO II. l. 140.
The mosaic history of Paradise and of Adam and Eve has been thought by
some to be a sacred allegory, designed to teach obedience to divine
commands, and to account for the origin of evil, like Jotham's fable
of the trees; Judges ix. 8. or Nathan's fable of the poor man and his
lamb; 2 Sam. xii. 1. or like the parables in the New Testament; as
otherwise knowledge could not be said to grow upon one tree, and life
upon another, or a serpent to converse; and lastly that this account
originated with the magi or philosophers of Egypt, with whom Moses was
educated, and that this part of the history, where Eve is said to have
been made from a rib of Adam might have been an hieroglyphic design of
the Egyptian philosophers, showing their opinion that Mankind was
originally of both sexes united, and was afterwards divided into males
and females: an opinion in later times held by Plato, and I believe by
Aristotle, and which must have arisen from profound inquiries into the
original state of animal existence.
ADDITIONAL NOTES. XI.
HEREDITARY DISEASES.
The feeble births acquired diseases chase,
Till Death extinguish the degenerate race.
CANTO II. l. 165.
As all the families both of plants and animals appear in a state of
perpetual improvement or degeneracy, it becomes a subject of
importance to detect the causes of these mutations.