what view is the study of the mathematics so generally recommended?
Not certainly for any practical purpose--not to make the bulk of
those who attend to them, astronomers or engineers. But simply to
exercise and strengthen the intellect--to give the mind a habit
of attention and of investigation. Now for all these purposes, if
I do not go so far as to assert that the mere ascertaining of the
names of insects is equal to the study of the mathematics, I have
no hesitation in affirming that it is nearly as effectual; and
with respect to giving a habit of minute attention, superior. Such
is the intricacy of nature, such the imperfection of our present
arrangements, that the discovery of the name of almost any insect
is a problem, calling in all cases for acuteness and attention, and
in some for a balancing of evidence, a calculation of the chances
of error, as arduous as are required in a perplexed law-case; and a
process of ratiocination not less strict than that which satisfies
the mathematician. In proof of which assertion I need only refer
any competent judge to the elaborate disquisitions of Laspeyres,
called for by one work alone on the lepidopterous insects of a single
district--the _Wiener Verzeichniss_, which occupy above two hundred
octavo pages[76], and must have cost the learned author nearly as
much labour of mind as the _Ductor Dubitantium_ did Bishop Taylor.
Do not apprehend that this occasional perplexity is any deduction
from the attractions of the science: though in itself, in some
respects, an evil, it forms in fact to many minds one of the chief of
them. The pursuit of truth, in whatever path, affords pleasure: but
the interest would cease if she never gave us trouble in the chase.
Horace Walpole used to say that from a child he could never bring
himself to attend to any book that was not full of proper names; and
the satisfaction which he felt in dry investigations concerning noble
authors and obscure painters, is experienced by many an entomologist
who spends hours in disentangling the synonymy of a doubtful species.
Nor would it be easy to prove that the wordy researches of the one
are not to every practical purpose as valuable as those of the other.
We smile at the Frenchman told of by Menage, that was so enraptured
with the study of heraldry and genealogy, as to lament the hard case
of our forefather Adam, who could not possibly amuse himself with
such investigations[77]. But many an entomologist who has felt the
delicious sensation attendant upon the indisputable ascertainment of
an insect's name after a long search, will feel inclined to indulge
in similar grief for the unhappy lot of his successors, when all
shall be smooth sailing in the science.
But in behalf of those who are more eminently entitled to be called
entomologists--those who, not content with collecting and investigating
insects, occupy themselves in naming and describing such as have
been before unobserved; in instituting new genera or reforming the
old; and, to say all in one word, in perfecting the system of the
science, still higher claims can be urged. Suppose that at this
moment our dictionaries of the French and German languages were so
very defective, that we were unable by the use of them to profit from
the discoveries of their philosophers; the labours of a Michaelis
being a sealed book to our theologists, and those of La Place to our
astronomers. On this supposition, would not one of the most important
literary undertakings be the compilation of more perfect dictionaries,
and would not the humblest contributor to such an end be deemed most
meritoriously engaged? Now precisely what an accurate dictionary of a
particular language is towards enabling the world to participate in
the discoveries published in that language, is a system of Entomology
towards enabling mankind to derive advantage from any discoveries
relative to insects. A good system of insects containing all the known
species, arranged in appropriate genera, families, orders and classes,
is in fact a dictionary, putting it within our power to ascertain the
name of any given insect, and thus to learn what has been observed
respecting its properties and history as readily as we determine the
meaning of a new word in a lexicon. In order to impress upon you more
forcibly the absolute need of such a system, I must enter into still
further detail.
There is scarcely a country in which several thousand insects may
not be found. Now, without some scientific arrangement, how is the
observer of a new fact respecting any one of them, to point out to
distant countries and to posterity the particular insect he had in
view? Suppose an observer in England were to find a certain beetle
which he had demonstrated to be a specific for consumption; and
that it was necessary that this insect, which there was reason to
believe was common in every part of the world, should be administered
in a recent state. Would he not be anxious to proclaim the happy
discovery to sufferers in all quarters of the globe? As his remedy
would not admit of transportation, he would have no other means than
by describing it. Now the question is, whether, on the supposition
that no system of Entomology existed, he would be able to do this, so
as to be intelligible to a physician in North America, for instance,
eager to administer so precious a medicine to his expiring patient?
It would evidently be of no use to say that the specific was a
beetle: there are thousands of different beetles in North America.
Nor would size or colour be any better guide: there are hundreds of
beetles of the same size and the same colour. Even the plant on which
it fed would be no sufficient clue; for many insects, resembling each
other to an unpractised eye, feed on the same plant; and the same
insect in different countries feeds upon different plants. His only
resource, then, would be a coloured figure and full description of
it. But every entomologist knows that there exist insects perfectly
distinct, yet so nearly resembling each other, that no engraving,
nor any language other than that strictly scientific, can possibly
discriminate them. After all, therefore, the chances are, that our
discoverer's remedy, invaluable as it might be, must be confined to
his own immediate neighbourhood, or to those who came to receive
personal information from him. But with what ease is it made known
when a system of the science exists! If the insect be already
described, he has but to mention its generic and trivial names, and
by aid of two words alone, every entomologist, though in the most
distant region--whether a Swede, a German, or a Frenchman; whether a
native of Europe, of Asia, of America, or of Africa, knows instantly
the very species that is meant, and can that moment ascertain whether
it be within his reach. If the species be new and undescribed, it
is only necessary to indicate the genus to which it belongs, the
species to which it is most nearly allied, and to describe it in
scientific terms, which may be done in few words, and it can at once
be recognised by every one acquainted with the science.
You will think it hardly credible that there should be so much
difficulty in describing an insect intelligibly without the aid of
system; but an _argumentum ad hominem_, supported by some other
facts, will, I conjecture, render this matter more comprehensible.
You have doubtless, like every one else, in the showery days of
summer, felt no little rage at the _flies_, which at such times take
the liberty of biting our legs, and contrive to make a comfortable
meal through the interstices of their silken or cotton coverings. Did
it, I pray, ever enter into your conception, that these blood-thirsty
tormentors are a different species from those flies which you are
wont to see extending the lips of their little proboscis to a piece
of sugar or a drop of wine? I dare say not. But the next time you
have sacrificed one of the former to your just vengeance, catch one
of the latter and compare them. I question if, after the narrowest
comparison, you will not still venture a wager that they are the very
same species. Yet you would most certainly lose your bet. They are
not even of the same genus--one belonging to the genus Musca (_M.
domestica_), and the other to the genus Stomoxys (_S. calcitrans_);
and on a second examination you will find that, however alike in
most respects, they differ widely in the shape of their proboscis;
that of the Stomoxys being a horny sharp-pointed weapon, capable
of piercing the flesh, while the soft blunt organ of the Musca is
perfectly incompetent to any such operation. In future, while you
no longer load the whole race of the house-fly with the execrations
which properly belong to a quite different tribe, you will cease
being surprised that an ordinary description should be insufficient
to discriminate an insect. It is to this insufficiency that we must
attribute our ignorance of so many of the insects mentioned by
the older naturalists, previously to the systematic improvements
of the immortal Linné: and to the same cause we must refer the
impossibility of determining what species are alluded to in the
accounts of many modern travellers and agriculturists who have been
ignorant of Entomology as a science. Instances without number of this
impossibility might be adduced, but I shall confine myself to two.
One of the greatest pests of Surinam and other low regions in South
America, is the insect called in the West Indies, where it is also
troublesome, the chigoe (_Pulex penetrans_), a minute species, to the
attacks of which I shall again have occasion to advert. This insect
is mentioned by almost all the writers on the countries where it is
found. Not less than eight or ten of them have endeavoured to give a
full description of it, and some of them have even figured it; and
yet, strange to say, it was not certainly known whether it was a flea
(_Pulex_, L.) or a mite (_Acarus_, L.), till a competent naturalist
undertook to investigate its history, and in a short paper in the
_Swedish Transactions_[78] proved that Linné was not mistaken in
referring it to the former tribe.
The second instance of the insufficiency of popular description is even
more extraordinary. In 1788 an alarm was excited in this country by the
probability of importing, in cargoes of wheat from North America, the
insect known by the name of the Hessian fly, whose dreadful ravages
will be adverted to hereafter. However the insect tribes are in
general despised, they had on that occasion ample revenge. The privy
council sat day after day anxiously debating what measures should be
adopted to ward off the danger of a calamity, more to be dreaded, as
they well knew, than the plague or pestilence. Expresses were sent
off in all directions to the officers of the customs at the different
outports respecting the examination of cargoes--dispatches written
to the ambassadors in France, Austria, Prussia, and America, to gain
that information of the want of which they were now so sensible: and
so important was the business deemed, that the minutes of council and
the documents collected from all quarters fill upwards of two hundred
octavo pages[79]. Fortunately England contained one illustrious
naturalist, the most authentic source of information on all subjects
which connect Natural History with Agriculture and the Arts, to whom
the privy council had the wisdom to apply; and it was by Sir Joseph
Banks's entomological knowledge, and through his suggestions, that
they were at length enabled to form some kind of judgement on the
subject. This judgement was after all, however, very imperfect. As Sir
Joseph Banks had never seen the Hessian fly, nor was it described in
any entomological system, he called for facts respecting its nature,
propagation, and economy, which could be had only from America. These
were obtained as speedily as possible, and consist of numerous letters
from individuals; essays from magazines; the reports of the British
minister there, &c. &c. One would have supposed that from these
statements, many of them drawn up by farmers who had lost entire crops
by the insect, which they profess to have examined in every stage,
the requisite information might have been acquired. So far however
was this from being the case, that many of the writers seem ignorant
whether the insect be a moth, a fly, or what they term a bug. And
though from the concurrent testimony of several its being a two-winged
fly seemed pretty accurately ascertained, no intelligible description
is given, from which any naturalist can infer to what genus it
belongs, or whether it is a known species. With regard to the history
of its propagation and economy the statements were so various and
contradictory, that though he had such a mass of materials before him,
Sir Joseph Banks was unable to reach any satisfactory conclusion.
Nothing can more incontrovertibly demonstrate the importance of
studying Entomology as a science than this fact. Those observations,
to which thousands of unscientific sufferers proved themselves
incompetent, would have been readily made by one entomologist well
versed in his science. He would at once have determined the order
and genus of the insect, and whether it was a known or new species;
and in a twelvemonth at furthest he would have ascertained in what
manner it made its attacks, and whether it were possible that it might
be transmitted along with grain into a foreign country; and on these
solid data he could have satisfactorily pointed out the best mode of
eradicating the pest, or preventing the extension of its ravages.
But it is not merely in travellers and popular observers that the
want of a systematic knowledge of Entomology is so deplorable.
A great portion of the labours of the profoundest naturalists
has been from a similar cause lost to the world. Many of the
insects concerning which Reaumur and Bonnet have recorded the most
interesting circumstances, cannot, from their neglect of system, be
at this day ascertained[80]. The former, as Beckmann[81] states on
the authority of his letters, was before his death sensible of his
great error in this respect: but Bonnet, with singular inconsistency,
constantly maintained the inutility of system, even on an occasion
when, from his ignorance of it, Sir James Smith, speaking of his
experiments on the barberry, found it quite impossible to make him
comprehend what plant he referred to[82].
So great is the importance of a systematic arrangement of insects. Yet
no such arrangement has hitherto been completed. Various fragments
towards it indeed exist. But the work itself is in the state of a
dictionary wanting a considerable proportion of the words of the
language it professes to explain; and placing those, which it does
contain, in an order often so arbitrary and defective, that it is
difficult to discover even the page containing the word you are in
search of. Can it be denied, then, that they are most meritoriously
employed who devote themselves to the removal of these defects--to the
perfecting of the system--and to clearing the path of future economical
or physiological observers from the obstructions which now beset it?
And who that knows the vast extent of the science, and how impossible
it is that a divided attention can embrace the whole, will contend that
it is not desirable that some labourers in the field of literature
should devote themselves entirely and exclusively to this object?
Who that is aware of the importance of the comprehensive views of a
Fabricius, an Illiger, or a Latreille, and the infinite saving of time
of which their inquiries will be productive to their followers, will
dispute their claim to rank amongst the most honourable in science?
II. No objection, I think, now remains against addicting ourselves to
entomological pursuits, but that which seems to have the most weight
with you, and which indeed is calculated to make the deepest impression
upon the best minds--I mean the charge of inhumanity and cruelty.
That the science of Entomology cannot be properly cultivated without
the death of its objects, and that this is not to be effected without
putting them to some pain, must be allowed; but that this substantiates
the charge of cruelty against us I altogether deny. Cruelty is an
unnecessary infliction of suffering, when a person is fond of torturing
or destroying God's creatures from mere wantonness, with no useful end
in view; or when, if their death be useful and lawful, he has recourse
to circuitous modes of killing them, where direct ones would answer
equally well. This is cruelty, and this with you I abominate; but not
the infliction of death when a just occasion calls for it.
They who see no cruelty in the sports of the field, as they are
called, can never, of course, consistently allege such a charge
against the entomologist; the tortures of wounded birds, of fish that
swallow the hook and break the line, or of the hunted hare, being,
beyond comparison, greater than those of insects destroyed in the
usual mode. With respect to utility, the sportsman, who, though he
adds indeed to the general stock of food, makes amusement his primary
object, must surely yield the palm to the Entomologist, who adds to
the general stock of mental food, often supplies hints for useful
improvements in the arts and sciences, and the objects of whose
pursuit, unlike those of the former, are preserved and may be applied
to use for many years.
But in the view even of those few who think inhumanity chargeable
upon the sportsman, it will be easy to place considerations which may
rescue the entomologist from such reproof. It is well known that, in
proportion as we descend in the scale of being, the sensibility of the
objects that constitute it diminishes. The tortoise walks about after
losing its head; and the polypus, so far from being injured by the
application of the knife, thereby acquires an extension of existence.
Insensibility almost equally great may be found in the insect world.
This, indeed, might be inferred _à priori_, since Providence seems
to have been more prodigal of insect life than of that of any other
order of creatures, animalcula perhaps alone excepted. No part of the
creation is exposed to the attack of so many enemies, or subject to so
many disasters; so that the few individuals of each kind which enrich
the valued museum of the entomologist, many of which are dearer to him
than gold or gems, are snatched from the ravenous maw of some bird or
fish or rapacious insect; would have been driven by the winds into the
waters and drowned; or trodden underfoot by man or beast,--for it is
not easy, in some parts of the year, to set foot to the ground without
crushing these minute animals; and thus also, instead of being buried
in oblivion, they have a kind of immortality conferred upon them.
Can it be believed that the beneficent Creator, whose tender mercies
are over all his works, would expose these helpless beings to such
innumerable enemies and injuries, were they endued with the same sense
of pain and irritability of nerve with the higher orders of animals?
But this inference is reduced to certainty, when we attend to the
facts which insects every day present to us, proving that the very
converse of our great poet's conclusion, as usually interpreted,
... The poor beetle that we tread upon,
In corporal sufferance finds a pang as great
As when a giant dies,
must be regarded as nearer the truth[83]. Not to mention the peculiar
organization of insects, which strongly favours the idea I am
inculcating, but which will be considered more properly in another
place, their sang-froid upon the loss of their limbs, even those that
we account most necessary to life, irrefragably proves that the pain
they suffer cannot be very acute. Had a giant lost an arm or a leg,
or were a sword or spear run through his body, he would feel no great
inclination for running about, dancing, or eating. Yet a crane-fly
(_Tipula_) will leave half its legs in the hands of an unlucky boy
who has endeavoured to catch it, and will fly here and there with
as much agility and unconcern as if nothing had happened to it; and
an insect impaled upon a pin will often devour its prey with as
much avidity as when at liberty. Were a giant eviscerated, his body
divided in the middle, or his head cut off, it would be all over with
him; he would move no more; he would be dead to the calls of hunger;
or the emotions of fear, anger, or love. Not so our insects. I have
seen the common cock-chafer walk about with apparent indifference
after some bird had nearly emptied its body of its viscera: a
humble-bee will eat honey with greediness though deprived of its
abdomen; and I myself lately saw an ant, which had been brought out
of the nest by its comrades, walk when deprived of its head. The
head of a wasp will attempt to bite after it is separated from the
rest of the body; and the abdomen under similar circumstances, if
the finger be moved to it, will attempt to sting. And, what is more
extraordinary, the headless trunk of a male Mantis has been known to
unite itself to the other sex[84]. These facts, out of hundreds that
might be adduced, are surely sufficient to prove that insects do not
experience the same acute sensations of pain with the higher orders
of animals, which Providence has endowed with more ample means of
avoiding them; and since they were to be exposed so universally to
attack and injury, this is a most merciful provision in their favour;
for, were it otherwise, considering the wounds, and dismemberments,
and lingering deaths that insects often suffer, what a vast increase
would there be of the general sum of pain and misery! You will now, I
think, allow that the most humane person need not hesitate a moment,
whether he shall devote himself to the study of Entomology, on
account of any cruelty attached to the pursuit.
But if some morbid sentimentalist should still exclaim, "Oh! but I
cannot persuade myself even for scientific purposes to inflict the
slightest degree of pain upon the most insensible of creatures--"
Pray, sir or madam, I would ask, should your green-house be infested
by Aphides, or your grapery by the semianimate Coccus, would this
extreme of tenderness induce you to restrict your gardener from
destroying them? Are you willing to deny yourself these unnecessary
gratifications, and to resign your favourite flowers and fruit at the
call of your fine feelings? Or will you give up the shrimps, which
by their relish enable you to play a better part with your bread and
butter at breakfast, and thus, instead of adding to it, contribute
to diminish the quantity of food? If not, I shall only desire you
to recollect that, for a mere personal indulgence, you cause the
death of an infinitely greater number of animals, than all the
entomologists in the world destroy for the promotion of science.
To these considerations, which I have no doubt you will think
conclusive as to the unreasonableness and inconsistency of the
objections made against the study of Entomology on the score of
cruelty, I shall only add that I do not intend them as any apology
for other than the most speedy and least painful modes of destroying
insects; and these will be pointed out to you in a subsequent letter.
Every degree of unnecessary pain becomes cruelty, which I need not
assure you I abhor; and from my own observations, however ruthlessly
the entomologist may seem to devote the few specimens wanted for
scientific purposes to destruction, no one in ordinary circumstances
is less prodigal of insect life. For my own part, I question whether
the drowning individuals, which I have saved from destruction, would
not far outnumber all that I ever sacrificed to science.
My next letter will be devoted to the _metamorphoses_ of insects, a
subject on which some previous explanation is necessary to enable
you to understand those distinctions between their different
states, which will be perpetually alluded to in the course of our
correspondence: and having thus cleared the way, I shall afterwards
proceed to the consideration of the _injuries_ and _benefits_ of
which insects are the cause.
I am, &c.
FOOTNOTES:
[43] Gen. ii. 19.
[44] Linn. _Fn. Suec._ Præf.
[45] Rom. i. 19, 20.
[46] Levit. xi. 21, 22. Lichtenstein in _Linn. Trans._ iv. 51, 52.
[47] Levit. xi. 20. conf. Bochart. _Hierozoic._ ii. l. 4. c. 9. 497-8.
[48] 1 Kings iv. 33.
[49] Luke xii. 27.
[50] Ibid. x. 19, 20.
[51] "Quæri fortasse à nonnullis potest, Quis Papilionum usus sit?
Respondeo, Ad ornatum Universi, et ut hominibus spectaculo sint: ad
rura illustranda velut tot bracteæ inservientes. Quis enim eximiam
earum pulchritudinem et varietatem contemplans mira voluptate non
afficiatur? Quis tot colorum et schematum elegantias naturæ ipsius
ingenio excogitatas et artifici penicillo depictas curiosis oculis
intuens, divinæ artis vestigia eis impressa non agnoscat et miretur?"
Rai. _Hist. Ins._ 109.
[52] _Nat. Theol._ 213.
[53] Kirby, in _Linn. Trans._ iv. 232. 235. See also a letter signed
C. in the _Gent. Mag._ for August 1795. This little insect produces
no _galls_ like the other species of the genus (Latr. Gen. _Crust.
et Ins._ iv. 253. Meig. _Dipt._ i. 94.), yet it corresponds with the
characters of _Cecidomyia_ laid down both by Latreille and Meigen.