The deleterious qualities of certain fishes have long been the subject of
medical conjectures. It is somewhat singular, and most difficult to
account for, that the same fish should be wholesome in some waters, and
deadly in others, although under the same latitude, and when, to all
appearance at least, no local cause can be discovered to which we might
reasonably attribute this fatal property. So powerful and prompt moreover,
it is in its action that rapid death will ensue whenever a small portion
of the fish has been eaten. Such, for instance, is generally the case with
the yellow-bill sprat, the _clypea thrissa_.
Some naturalists attribute this poison to copper banks, on or near which
the fish may feed. The absurdity of this opinion has been fully
demonstrated; in the first instance, no such copper banks have been
discovered in the West Indies, and these fish abound on the coasts of
islands of coral formation. Moreover, it is not likely that this mineral
should saturate the animal; and, even if it could produce this effect, the
entire body would in all probability be affected, whereas the poison seems
to lie in particular parts, chiefly in the intestines, the liver, the fat,
&c. This is evident from the practice of fishermen, who can eat poisonous
fish with impunity if they have taken the precaution to draw them
carefully and salt them. In addition to these observations, the symptoms
of the disease thus produced, by no means resemble those of mineral
poisons. Dr. Chisholm, who pretends that copper banks do exist in the
Windward Islands, is of this opinion. Admitting the facts, it may be
asked, have the waters of these seas been impregnated by the copper? if
they are not, how can its influence extend to its inhabitants? and why are
particular fish only affected? Moreover, although it is well known that
certain substances are deleterious to some animals and harmless to others,
yet one might fancy that, if the coppery principal of an animal's flesh
could poison, it is not irrational to think that the same deadly substance
would also destroy the animal. The presence of this mineral has never been
detected by any chemical test; and, if the poison consisted in copper, how
could salting the fish destroy it? In opposition to these objections, it
has been maintained that fish may be rendered poisonous by feeding on the
marine plants that grow upon these deadly banks. Now, unless it could be
proved that copper is not injurious to fish, these same lithophyta and
zoophyta would no doubt poison them.
However, it is more than probable that it is to a certain injurious food
that these dangerous qualities are to be referred. Various plants that
grow in these regions are of a poisonous nature to man, although, as I
have just observed, they may not be so destructive to fish. The
circumstance of the alimentary tube being more poisonous than any other
part seems to warrant the conclusion; and I have observed in the West
Indies, that the crabs that feed upon banks where the manchineel is to be
found, frequently occasion serious, and sometimes fatal accidents. On the
coast of Malabar, crabs are poisonous in the month of October, when the
_blue tithymale_ abounds.
Whatever may be the causes of this deadly principle, the effects are most
rapid. When a large quantity has been taken, the patient soon dies in
strong convulsions; but frequently, when the quantity and the nature of
the poison have not been sufficient to occasion death, the body becomes
emaciated, the cuticle peels off, particularly on the palms of the hands
and the soles of the feet, the hair drops, acute pains shoot through every
joint, and the sufferer not unfrequently sinks under a lingering disease.
In these cases change of climate has been found the most effectual remedy,
and a return to Europe becomes indispensable.
The usual symptoms that denote the presence of the poison, are languor,
heaviness, drowsiness, great restlessness, flushing of the face, nausea,
griping, a burning sensation, at first experienced in the face and eyes,
and then extending over the whole body; the pulse, at first hard and
frequent, soon sinks, and becomes slow and feeble. In some cases the
salivary glands become tumefied with a profuse salivation; and the body,
and its perspiration, are as yellow as in the jaundice. These peculiar
symptoms have frequently been known to arise after eating the _rock-fish_.
The remedies that are usually resorted to are stimulants. Capsicum has
been considered a powerful antidote; and the use of ardent spirits or
cordials has also been strongly urged. It has been observed, that persons
who had drunk freely, or who had taken a dram after eating fish that had
disordered others, were, comparatively speaking, exempt from the severity
of the disease. A decoction of the root of the _sour-sop_, and an infusion
of the flowers of the _white cedar_ and the _sensitive plant_ have also
been advised by several West India practitioners.
The practice of putting a silver spoon in the water in which fish is
boiled, to ascertain its salubrity, is a popular test that cannot be
depended on. Fishermen have observed that fish that have no scales are
more apt to prove injurious; and those of uncommon size are looked upon as
the most dangerous.
To ascertain whether the nature of the fishes' food could thus render them
poisonous, Mr. Moreau de Jonnes had recourse to many curious experiments.
He took portions of polypes found in the waters reputed dangerous, more
particularly the _liriozoa Caribaea_, the _millepora polymorpha_, the
_gorgonia pinnata_, the _actinia anemone_, &c., and, having enveloped them
in paste, he fed fishes with them; but in no one instance was any
prejudicial result observed. He tried in the same manner the _physalis
pelagica_ of Lamark, which contains an acrid and caustic fluid; but the
fish invariably refused it, nor would they touch fragments of the
manchineel apple.
Oysters have been known to produce various accidents; and, when they were
of a green colour, it has been supposed that this peculiarity was also due
to copper banks. This is an absurdity; the green tinge is as natural to
some varieties as to the _esox belone_, whose bones are invariably of the
same hue as verdigrise. Muscles frequently occasion feverish symptoms,
attended with a red, and sometimes a copper-coloured, efflorescence over
the whole body. These accidents appear to arise from some peculiar
circumstances. In Boulogne I attended a family in which all the children
who had eaten muscles were labouring under this affection, while not
another instance of it was observed in the place. In the Bahama Islands I
witnessed a fatal case in a young girl who had eaten crabs; she was the
only sufferer, although every individual in the family had shared in the
meal. The idea of the testaceous mollusca avoiding copper-bottomed
vessels, while they are found in abundance on those that are not sheathed,
is absurd; this circumstance can be easily explained by the greater
facility these creatures find in adhering to wood. There is every reason
to believe, that the supposed poisonous oysters found adhering to the
copper bottom of a ship in the Virgin Isles, and the occasional accidents
amongst the men that ate them, were only so in the observer's imagination,
and that part of the ship's company were affected by some other causes.
Another report, equally absurd, was that of the fish having gradually
quitted the Thames and Medway since coppering ships' bottoms has been
introduced! The following may be considered the fish that should be
avoided:
The Spanish mackerel, _Scomber caeruleo-argenteus_.
The yellow-billed sprat, _Clupea thrissa_.
The baracuta, _Esox baracuta_.
Grey snapper, _Coracinus fuscus_.
The porgie, _Sparus chrysops_.
The king-fish, _Scomber maximus_.
The hyne, _Coracinus minor_.
Bottle-nosed cavallo, _Scomber_.
Old wife, _Balistes monoceros_.
Conger eel, _Muraena major_.
Sword-fish, _Xiphias gladius_.
Smooth bottle-fish, _Ostracion globellum_.
Rock-fish, _Perca manna_.
I have known accidents arise from the use of the dolphin on the high seas;
and, while I was in the West Indies, a melancholy instance of the kind
occurred, when the captain, mate, and three seamen of a trading vessel
died from the poison; a passenger, his wife, and a boy, were the only
survivors, and were fortunately picked up in the unmanageable vessel.
The above catalogue of poisonous fishes is extracted from Dr. Dancer's
"Jamaica Practice of Physic," and its correctness fell under my own
observation in the Wrest Indies. The different systems and classifications
of ichthyologists have produced much confusion, and may lead to fatal
errors; I think it therefore advisable to submit to travellers, who may
have to visit these unhealthy regions, the names of the _toxicophorous_
fishes according to the French momenclature.
Le poisson arme, _Diodon orbicularis_.
La lune, _Tetraodon mola_.--LINN.
Le tetraodon ocelle, _T. ocellatus_.
Le t. scelerat, _T. scelreatus_.
La vieille, _Balistes vetula_.
La petite vieille, { _B. monoceros_.--LINN.
{ _Alutus monoceros_.--CUVIER.
Le coffre triangulaire, _Ostracion trigonus_.--BLOCH.
La grande orphie, _Esox Brasiliensis_.--LINN.
La petite orphie, _E. marginatus_.--LACEPEDE.
Le congre, _Muraena conger_.--MINN.
Le perroquet, _Sparus psittacus_.--LACEPEDE.
Le capitaine, _S. erythrinus_.--BLOCH.
La becune, _Sphyraena becuna_.
Le thon, _Scomber thynnus_.--LINN.
La carangue, _Caranx carangus_.
A work, in which a _synonymous_ catalogue of all the fishes supposed to be
poisonous might be found, would be highly desirable, as they generally
bear different popular and scientific names, thus producing a dangerous
confusion even amongst naturalists; how much more dangerous amongst
seafaring people and voyagers!
I cannot conclude this article without noticing the singular properties of
those electric fishes denominated the _torpedo-ray_ and the _gymnote_.
They had been long known to naturalists, and the ancients attributed their
destructive faculties to a magic power that Oppian had recorded in his
_Alieuticon_, where he describes a fisherman palsied through the hook, the
line, and the rod. This influence being voluntary on the part of the
animal, seemed to warrant the belief in its mischievous nature, since it
allows itself sometimes to be touched with impunity, while at others it
burrows itself under the sand of the beach, when the tide has receded, and
maliciously benumbs the astonished passenger who walks over it. This
singular fish, which is common in the Mediterranean Sea, has been
described both by the Greek and Roman writers; amongst others, by
Aristotle and Athenaeus: and Socrates, in his Dialogues, compares a
powerful objection, to the influence of the torpedo.
This voluntary faculty has been observed by Lacepede and Cloquet in the
Mediterranean, and at La Rochelle. In torpedos kept in water for
experimental purposes, Reaumur found that he handled them without
experiencing any shock for some time, until they at last appeared to
become impatient: he then experienced a stunning sensation along the arm,
not easily to be described, but resembling that which is felt when a limb
has been struck with a sudden blow. One of the experiments of this
naturalist proved the extensive power of this faculty. He placed a torpedo
and a duck in a vessel containing sea-water, covered with linen to prevent
the duck from escaping, without impeding the bird's respiration. At the
expiration of a few minutes the animal was found dead, having been killed
by the electric shocks of its enemy.
Redi was the first who demonstrated this faculty. Having laid hold of a
torpedo recently caught, he had scarcely touched it, when he felt a
creeping sensation shooting up to the shoulder, followed by an unpleasant
tremor, with a lancinating pain in the elbow. These sensations he
experienced as often as he touched the animal; but this faculty gradually
decreased in strength as the animal became exhausted and dying. These
experiments he related in a work entitled "_Esperienze intorno a diverse
cose naturali_." Florence, 1671.
In 1774, Walsh made some very interesting experiments at the Isle of Re
and La Rochelle, and clearly demonstrated this electric faculty in a paper
_On the electric property of the torpedo_. In one of them he found that
this fish could produce from forty to fifty shocks in the course of ninety
minutes. The electrified individuals were isolated; and at each shock the
animal gave, it appeared to labour under a sense of contraction, when its
eyes sunk deep in their sockets.
The _trichiurus electricus_ of Linnaeus, the _rhinobatus electricus_ of
Schneider, and the _gymnonotus electricus_ of _Surinam_, are the species
of this singular fish with which experiments have chiefly been made. The
_gymnonotus_ is a kind of eel, five or six feet in length, and its
electric properties are so powerful that it can throw down men and horses.
This animal is rendered more terrific from the velocity of his powers of
natation, thus being able to discharge its thunder far and near. When
touched with one hand the shock is slight; but when grasped with both, it
is so violent that, according to the accounts of Collins Flag, the
electric fluid can paralyze the arms of the imprudent experimentalist for
several years. This electric action is analogous to that which is obtained
by means of the fulminating plate, which is made of glass with metallic
plates. Twenty-seven persons holding each other by the hands, and forming
a chain, the extremities of which corresponded with the points of the
fish's body, experienced a smart shock. These shocks are produced in quick
succession, but become gradually weaker as the fluid appears to be
exhausted. Humboldt informs us, that, to catch this fish, wild horses are
driven into the water, and after having expended the fury and the vigour
of the gymnonotus, fishermen step in and catch them either with nets or
harpoons. Here we find that the irritable or sensorial power is exhausted
through the medium of electricity. These phenomena may be attributed to an
electric or Voltaic aura; and the organ of the animal that secretes the
fluid resembles in its wonderful structure the Voltaic apparatus. Both the
gymnote and the torpedo obey the laws of electricity, and their action is
limited to the same conducting and non-conducting mediums. The electric
sparks proceeding from the gymnote have been plainly seen in a dark
chamber by Walsh, Pringle, Williamson, and others. The fish has four
electric organs, two large and two small ones, extending on each side of
the body from the abdomen to the end of the tail. These organs are of
such a size that they constitute one third of the fish's bulk. Each of
them is composed of a series of aponeurotic membranes, longitudinal,
parallel, horizontal, and at about one line's distance from each other.
Hunter counted thirty-four of these fasciculi in one of the largest. Other
membranes or plates traverse these vertically, and nearly at a right
angle; thus forming a plexus or net-work of numerous rhomboidal cells.
Hunter found no less than two hundred and forty of these vertical plates
in the space of eleven inches.
This apparatus, analogous to the Voltaic pile, is brought into action by a
system of nerves rising from the spinal marrow, each vertebra giving out a
branch; other branches, rising from a large nerve, running from the basis
of the cranium to the extremity of the tail. All these ramifications are
spread and developed in the cells of the electric organs, to transmit its
powerful fluid, and strike with stupor or with death every animal that
comes within its reach. Lacepede has justly compared this wonderful
mechanism to a battery formed of a multitude of folio-electric pieces.
The electric organ of the _malapterus electricus_ is of a different
formation. This fish, found in the Nile and in other rivers of Africa, is
called by the Arabs _raash_ or thunder. In this animal the electric fluid
extends all round the body, immediately under the integuments, and
consists of a tissue of cellular fibres so dense, that it might be
compared to a layer of bacon; but, when carefully examined, it consists of
a series of fibres forming a complex net-work. These cells, like those in
the gymnote, are lubricated with a mucous secretion. The nervous system of
this intricate machinery is formed by the two long branches of the
pneumo-gastric nerves, which in fishes usually run under each lateral
line. Here, however, they approach each other on leaving the cranium,
traversing the first vertebra.
Linnaeus had classed the torpedo in the genus _ray_, and hence called it
_raia torpedo_. Later naturalists have restored to it its ancient name, as
given by Pliny, and termed it _torpedo_, of which four species are
described: the _T. narke_, or with five spots; the _T. unimaculata_,
marked, as the name indicates, with one spot; the _T. marmorata_, and the
_T. Galvanni_.
The ancients placed much faith in the medicinal properties of these
fishes. Hippocrates recommends its roasted flesh in dropsies that follow
liver affections. Dioscorides prescribed its application in cases of
obstinate headaches and rheumatisms. Galen and other physicians recommend
the application of the living animal; and Scribonius Largus states that
the freedman Anteroes was cured of the gout by this practice. To this day,
in Abyssinia, fever patients are tied down on a table, and a torpedo is
applied to various parts of the body. This operation, it is affirmed,
causes great pain, but is an infallible remedy.