wine; set it in a warm place, and shake it often for four days; then
filter off the clear tincture. Put an inch depth of this into a cup,
and set upright in it pieces of the rind of ash, white willow, and
ozier, prepared as has been directed, by maceration in water; for in
that way one trouble serves for an hundred kinds. Let an inch of the
rinds also stand up out of the tincture. After twenty-four hours take
them out, clip off the part which was immersed in the fluid, and save
the rest for observation.
TO PREPARE THE BLEA.
Cut the pieces in a fit season, either just before the first leaves of
Spring, or in the Midsummer shooting time. Then we see all the wonders
of the structure; the thousands of mouths which open throughout the
course of these innumerable vessels, to pour their fluid into the
interstitial matter.
These vessels, which are in nature cisterns of sap for the feeding the
growth of the whole tree, are so large, that they are capable of being
filled with coloured wax, in the manner of the vessels in anatomical
injections; and this way they present pleasing objects for the
microscope, and afford excellent opportunities of tracing their course
and structure.
A METHOD OF FILLING THE SAP VESSELS OF PLANTS.
A great many shoots of the scarlet and other oaks are to be taken off in
the Spring; they must be cut into pieces of about two inches in length,
and immediately from the cutting they must drop into some warm rain
water: in this they are to stand twenty-four hours, and then be boiled a
little. When taken out, they are to be tied on strings, and hung up in a
place where the air passes freely, but the sun does not shine. When they
are perfectly dry, a large quantity of green wax, such as is used for
the seals of law deeds, is to be gently melted in an earthen pipkin set
in water; the water to be heated and kept boiling. As soon as the wax
runs, the sticks are to be put in, and they are frequently to be stirred
about. They must be kept in this state about an hour, and then the
pipkin is to be taken out of the water, and set upon a naked fire, where
it is to be kept with the wax boiling for two or three hours; fresh
supplies of the same wax being added from time to time.
After this it is to be removed from the fire, and the sticks immediately
taken out with a pair of nippers; when they are cold, the rough wax
about them is to be broken off. Both ends of each stick are to be cut
off half an inch long, and thrown away, and the middle pieces saved.
These are then to be cut in smaller lengths, smoothed at the ends with a
fine chissel, and many of them split in various thicknesses.
Thus are obtained preparations, not only of great use, but of wonderful
beauty. Many trees this way afford handsome objects as well as the oak;
and in some, where the sap vessels are few, large, and distinct, the
split pieces resemble striped satins, in a way scarce to be credited. It
is in such that the outer coats of these vessels are most happily of all
to be examined.
THE METHOD OF PREPARING SALTS AND SALINE SUBSTANCES, FOR THE VIEWING
THEIR CONFIGURATIONS.
Dissolve the subject to be examined in no larger a quantity of river or
rain water than is sufficient to saturate it; if it be a body easily
dissoluble, make use of cold water, otherwise make the water warm or
hot, or even boiling, according as you find it necessary. After it is
perfectly dissolved, let it rest for some hours, till, if over-charged,
the redundant saline particles are precipitated, and settle at the
bottom, or shoot into crystals; by which means you are most likely to
have a solution of the same strength at one time as at another; that is,
a solution fully charged with as much as it can hold up, and no more;
and by these precautions the configurations appear alike, how often
soever tried: whereas, if the water be less saturated, the proportions,
at different times, will be subject to more uncertainty; and if it be
examined before such separation and precipitation of the redundant
salts, little more will be seen than a confused mass of crystals.
The solution being thus prepared, take up a drop of it with a goose
quill, cut in fashion of a scoop, and place it on a flat slip of glass,
of about three quarters of an inch in width, and between three and four
inches long, spreading it on the glass with the quill, in either a round
or oval figure, till it appears a quarter of an inch or more in
diameter, and so shallow as to rise very little above the surface of the
glass. When it is so disposed, hold it as level as you can over the
clear part of a fire that is not too fierce, or over the flame of a
candle, at a distance proportionable to the degree of heat it requires,
which experience only can direct, and watch it very carefully till you
discover the saline particles beginning to gather and look white, or of
some other colour, at the extremities of the edges; then having adjusted
the microscope before-hand for its reception, armed with the fourth
glass, which is the fittest for most of these experiments, place it
under your eye, and bring it exactly to the focus of the magnifier; and
after running over the whole drop, fix your attention on that side where
you observe any increase or pushing forwards of crystalline matter from
the circumference towards the center.
This motion is extremely slow at the beginning, unless the drop has been
over-heated, but quickens as the water evaporates, and in many kinds,
towards the conclusion, produces configurations with a swiftness
inconceivable, composed of an infinity of parts, which are adjusted to
each other with an elegance, regularity, and order, beyond what the
exactest pencil in the world, guided by the ruler and compass, can ever
equal, or the most luxurious imagination fancy.
When action once begins, the eye cannot be taken off, even for a moment,
without losing something worth observation; for the figures alter every
instant, till the whole process is over; and in many sorts, after all
seems at an end, new forms arise, different entirely from any that
appeared before, and which probably are owing to some small quantity of
salt of another kind, which the other separates from, and leaves to act
after itself has done; and in some subjects three or four different
sorts are observable, few or none being simple and homogeneous.
When the configurations are fully formed, and all the water evaporated,
most kinds of them are soon destroyed again by the moisture or action of
the air upon them; their points and angles lose their sharpness, become
uneven and defaced, and moulder as it were away; but some few are
permanent, and by being inclosed between glasses, they may be preserved
months or even years.
It happens oftentimes that a drop of a saline solution can hardly be
spread on the slip of glass, by reason of the glass’s smoothness, but
breaks into little globules, as it would do were the surface greasy: the
way to prevent this is, by rubbing the broken drop with your finger over
the glass, so as to leave the glass smeared with it; on which smeared
place, when dry, another drop of the solution may be spread very easily
in whatever form is agreeable.
It sometimes happens, that when a heated drop is placed properly for
examination, the observer finds such a cloudiness that he can
distinguish nothing of the object; which is owing to saline steams that
arise from the drop, covering and obscuring the object glass, and
therefore must immediately be wiped away with a soft cloth or leather.
In all examinations of saline solutions by the microscope, even though
made in the day-time, you must use a candle; for the configurations,
being exceedingly transparent, are rendered much more distinguishable by
the brown light a candle affords, than by the more white and transparent
day-light; and besides, either by moving the candle, or turning the
microscope, such light may be varied or directed just as the subject
requires.
It may be also proper to take notice, that no kinds of microscopes are
fit for these observations, but such as have an open stage, whereon the
slips of glass, with the liquor upon them, may be placed readily, and in
a perfect horizontal position; and moreover, where they can be turned
about freely, and without disordering the fluid.
CHAP. V.
THE IMPORTANCE OF NATURAL HISTORY; OF INSECTS IN GENERAL, AND OF THEIR
CONSTITUENT PARTS.
There is no human science which to a rational mind exhibits a greater
variety of attractions, or which is more deserving of general esteem,
than that of NATURAL HISTORY; accordingly we find, that from the
earliest times in which the sciences have been promulgated, it has never
been entirely destitute of its votaries; but, on the contrary, has for
ages employed the lives of many learned men, as being, in fact, the
study of DIVINE WISDOM displayed in the creation: the farther our
researches are carried, the more striking proofs of it every where
abound. In the present century, an æra particularly devoted to
investigation, and propitious to discovery and improvement in various
branches of science, Natural History, so far from being neglected, has
been more generally cultivated, and pursued with an ardor unprecedented
at any former period. Men of the first rank in literature have become
indefatigable labourers in the vast and unbounded field which it
presents to the eyes of an accurate and attentive observer. The animal,
the vegetable, and the mineral kingdoms, have been examined with the
utmost care; that confusion and perplexity which seemed unavoidably to
result from a view of the immense variety of articles contained in each
of those departments, and which frequently deterred persons from
engaging in the pursuit, have been in a great measure removed by the
introduction of systematic arrangement; by these means, the various
subjects are distributed into classes and genera, enabling us to form
distinct and comprehensive ideas of them. To the same methodical plan,
and the nicety of discrimination thence arising, we must attribute the
discovery and description of many new species; this has excited an
emulation still farther to pursue the inquiry, nor need any apprehension
be entertained that the subject will be exhausted, as, no doubt, an
infinite variety still remains unexplored to engage the utmost attention
of the philosophic mind, and fully to compensate the pains bestowed on
so interesting a branch of knowledge.
Of the abundance of articles enumerated in books of Natural History,
there are comparatively few, whose uses are as yet known, or their
properties fully understood. The true naturalist should always bear in
mind that there is a vast difference between retaining the names, and
investigating the nature and peculiar qualities of the creatures to
which they belong. It is highly proper, indeed necessary, that the
multifarious objects of Natural History should be well ascertained and
distinguished with nicety in all their varieties; the science and
admirers of it are, therefore, unquestionably indebted to the able
naturalists who have devoted their time, and exercised their ingenuity
in devising commodious methods of arrangement, and invented systems for
identifying the several subjects with accuracy, and less danger of
fallacy or mistake: but all who are, or would wish to be thought
naturalists, ought to consider, that the best possible mode of
classification is, after all, but an introduction to Natural History.
The ingenious and indefatigable LINNÆUS, who spent his life in
fabricating the curious system now generally adopted, intended it
certainly for the improvement of the science, as a basis for the service
of knowledge and the benefit of mankind; let us be cautious not to
mistake the means for the end, but in the prosecution of the science,
think of the true ends of knowledge, and endeavour to promote our own
instruction, and the advancement of others, with a view to the adoration
of that DIVINE BEING to whom all creation is indebted for existence, and
their application to the occasions and uses of life, all along
conducting and perfecting the study in the spirit of benevolence.
The study of nature, or in other words, a serious contemplation of the
works of GOD, is indeed a great and proper object for the exercise of
our rational faculties; nor can we perhaps employ them better, than in
endeavouring to make ourselves acquainted with the works of that
glorious Being from whom they were received.
Though there is a great deal of pleasure in contemplating the material
world, or that system of bodies into which the DIVINE ARCHITECT has so
admirably wrought the mass of dead matter, with the several relations
which those bodies bear to one another; there is still something more
wonderful and surprizing arising from the contemplation of the animated
world; by which is to be understood all those animals with which every
part of the universe is furnished. The material world is only the shell
of the universe; the animated world are its inhabitants.
Existence is a blessing to those beings only which are endowed with
perception, and appears useless when bestowed upon dead matter, any
farther than as it is subservient to beings which are conscious of their
existence. Thus we find, from the bodies which lie under our
observation, that matter is only made as the basis and support of
animals, and that there is no more of the one than what is necessary for
the exigence of the other.
There are some living creatures which are raised but just above dead
matter; there are many others, but one remove from these, which have no
other senses but those of feeling and taste; others have still an
additional sense of hearing; others of smell, and again others of sight.
It is wonderful to observe, by what a gradual progress life advances
through a prodigious variety of species, before a creature is formed
that possesses all these senses; and even among these, there is such a
different degree of perfection in the senses which one animal enjoys
beyond what appears in another, that, though the sense in different
animals be distinguished by the same common denomination, it seems
almost of a different nature. If, after this, we look into the several
inward qualities of sagacity, or what is generally called instinct, we
find them rising after the same manner imperceptibly one above another,
and receiving additional improvements, according to the species in which
they are implanted. This progress in nature is so very gradual, that
what appears to us the most perfect of an inferior species, comes very
near to the most imperfect, as we are accustomed to call it, of that
which is immediately above it.
The exuberant and overflowing goodness of the SUPREME BEING, whose mercy
extends to all his works, is plainly seen, as before observed, from his
having made so very little matter, at least what falls within our
knowledge, that does not swarm with life; nor is his goodness less
visible in the diversity than in the multitude of living creatures. Had
he only made one species of animals, none else could have enjoyed the
happiness of existence; he has, therefore, included in his creation,
every degree of life, every capacity of being. The whole chasm of
nature, from a plant to a man, is filled up with diverse kinds of
creatures, rising one above another, by such a gentle and easy ascent,
that the little transitions and deviations from one species to the other
are almost insensible. This intermediate space is so prudently managed,
that there is scarce a degree of perception which does not appear in
some one part of the animated world. Is the goodness or the wisdom of
the DIVINE BEING more manifest in this his proceeding?
In this system of creation there is no creature so wonderful in its
nature, and which so much merits our particular attention, as man, who
fills up the middle space between the animal and intellectual nature,
the visible and invisible world; and is that link, in the chain of
beings, which has been often termed the “nexus utriusque mundi.” So that
he, who in one respect being associated with angels and arch-angels, may
look upon a BEING of infinite perfection as his father, and the highest
order of spirits as his brethren, may, in another respect, say to
corruption, “Thou art my father, and to the worm, thou art my mother and
my sister.”[46]
[46] Spectator, Vol. vii. Numb. 519.
There are, however, many who form their judgments of the works of nature
from external appearance only; hence they imagine, that the greatest and
most magnificent are the only perfect parts of creation, and worthy of
our regard. Hence they confine their attention to the more splendid and
shining branches of philosophy, and are too apt to treat the other parts
with coolness and indifference, not to say contempt.
But surely a true philosopher is one who diligently pursues the study of
nature in all its branches; who can behold with admiration her noblest
productions, yet view with pleasure the smallest of her works: in short,
one who thinks every thing excellent that owes its formation to the GOD
of nature; and we need only take a transient view of the smaller
creatures with which the earth is peopled, to discover that they are
perfect in their kind, and carry about them as strong marks of infinite
wisdom, power, and beneficence as the greatest. It has been justly said,
“that there is not a vegetable that grows, nor an insect that moves, but
what is sufficient to confound the Atheist, and to afford the candid
observer endless materials for devout adoration and praise.”
If we examine insects with attention, we shall soon be convinced of
their divine origin, and survey with admiration the wonderful art and
mechanism of their structure, wherein such a number of vessels, parts,
and movements are collected in a single point; yet are they furnished
with weapons to seize their prey, dexterity to escape their foes, every
thing requisite to perform the business of their stations, and enjoy the
pleasures of their conditions. What a profusion of the richest ornaments
and the gayest colours are often bestowed on one little insect! and yet
there are thousands of others that are as beautiful and wonderful in
their kind; some are covered with shining coats of mail, others are
adorned with plumes of feathers, all of them furnished with every thing
that is proper to make them answer the purposes for which they were
designed.
“After an attentive examination of the nature and fabric of both the
least and largest animals, I cannot,” says the great and excellent
Swammerdam, “but allow the less an equal, perhaps a superior degree of
dignity; whoever duly considers the conduct and instinct of the one,
with the manners and actions of the other, must acknowledge, that they
are all under the direction and controul of a supreme and particular
intelligence; which, as in the largest it extends beyond the limits of
our comprehension, escapes our researches in the smallest. If, while we
dissect with care the larger animals, we are filled with wonder at the
elegant disposition of their limbs, the inimitable order of their
muscles, and the regular direction of their veins, arteries, and
nerves, to what an height is our astonishment raised, when we discover
all the parts arranged in the least, and in the same regular manner! How
is it possible but we must stand amazed when we reflect, that those
little animals, whose bodies are smaller than the point of the
dissecting knife, have muscles, veins, arteries, and every other part
common to the larger animals? Creatures so very diminutive, that our
hands are not delicate enough to manage, or our eyes sufficiently acute
to see them.”
The subserviency of the several beings in the visible creation to one
another; the order in which each of them appears in that appointed
season, when only it can be conducive to the purposes of the rest; and
the preservation of a sufficient number of every species, amidst the
immense havoc that reigns throughout, are, among other things, proofs of
the amazing and incomprehensible wisdom by which they were all formed.
With what pleasure does the mind, accustomed to look up from effects to
their causes, from created beings to the GREAT SOURCE OF BEING, view
that unbounded beneficence, which leaves not the smallest space, capable
of supporting existence of any kind, unplanted with them. There is
hardly any portion of matter, or the least drop of fluid naturally found
on the surface of the earth, that is not inhabited by multitudes of
animals; the subterraneous regions are peopled with their minute
inhabitants, and the abyss of the sea, where no human eye can penetrate,
abounds with animated beings.
The air is usually considered as the great source of destruction to
bodies, whether animal or vegetable; but we do not always understand by
what means or in what manner it is performed. What we term destruction
and decay of one substance, occasions the production and ripening a
multitude of others; wherever the air is admitted, with it a thousand
different things find their way; and what is usually attributed to the
effects of that fluid, is in general occasioned by the multitudes of
bodies with which it is fraught. Redi observed, that flesh preserved
from the access of flies, would bread no maggots; and it is as constant
an observation, that vegetable substances will keep a long time in
whatever state they are, if the air be excluded; but as soon as it is
admitted, they also produce or afford their several kinds either of
animal, or minuter vegetable inhabitants. In the first of these cases,
the parent flies make their way to the exposed flesh, and there deposit
their eggs for the production of a new offspring; in the other,
multitudes of the seeds of minute plants and ovula of animals are
floating in the air, and accompany it wherever it enters; if they be
thus deposited in a place proper for vegetation and accretion, they
burst their inclosures, and attain their growth as regularly as the
seeds of plants deposited in the earth, or the eggs of larger animals in
the nest.
The same wisdom which placed the sun in the center of the system, and
arranged the several planets around him in their order, has no less
shewn itself in the provision made for the food and dwelling of every
bird that roams in the air, and every beast that wanders in the desert;
equally great in the smallest and in the most magnificent objects; in
the star and in the insect; in the elephant and in the fly; in the beam
that shines from heaven and in the grass that cloathes the ground.
Nothing is overlooked, nothing is carelessly performed: every thing that
exists is adapted with perfect symmetry to the end for which it was
designed. This wisdom displayed by the Almighty in the creation, was not
intended merely to gratify curiosity and to raise wonder; it ought to
beget profound submission, and pious trust in every heart.
Histories of the providence and caution, the care and foresight of the
most inconsiderable among animal beings, must surely ever be read with
pleasure and attention, as conveying a most beautiful lesson to a
reflecting mind; it is impossible for any one thus instructed to think
that the Great Being, who has been so careful of those inferior
creatures, can be regardless of him whom he has placed in a station
infinitely more exalted. Throughout the whole system of things, we
behold a manifest tendency to promote the benefit either of the rational
or the animal creation. In some parts of nature, this tendency may be
less obvious than in others. Objects, which to us seem useless or
hurtful, may sometimes occur; and strange it were, if in so vast and
complicated a system, difficulties of this kind should not occasionally
present themselves to beings, whose views are so narrow and limited as
ours. It is well known, that in proportion as the knowledge of nature
has increased among men, these difficulties have diminished.
Satisfactory accounts have been given of many perplexing appearances;
useful and proper purposes have been found to be promoted by objects
which were at first thought to be unprofitable or noxious.[47]