Part 24 (1/2)
_Note_.--This can be thickened with tomatoes, and vermicelli served in it, which makes it a very tasteful soup.
[Ill.u.s.tration: THE PRAWN.]
THE PRAWN.--This little fish bears a striking resemblance to the shrimp, but is neither so common nor so small. It is to be found on most of the sandy sh.o.r.es of Europe. The Isle of Wight is famous for shrimps, where they are potted; but both the prawns and the shrimps vended in London, are too much salted for the excellence of their natural flavour to be preserved. They are extremely lively little animals, as seen in their native retreats.
[Ill.u.s.tration]
FISH.
CHAPTER VII.
THE NATURAL HISTORY OF FISHES.
199. IN NATURAL HISTORY, FISHES form the fourth cla.s.s in the system of Linnaeus, and are described as having long under-jaws, eggs without white, organs of sense, fins for supporters, bodies covered with concave scales, gills to supply the place of lungs for respiration, and water for the natural element of their existence. Had mankind no other knowledge of animals than of such as inhabit the land and breathe their own atmosphere, they would listen with incredulous wonder, if told that there were other kinds of beings which existed only in the waters, and which would die almost as soon as they were taken from them. However strongly these facts might be attested, they would hardly believe them, without the operation of their own senses, as they would recollect the effect produced on their own bodies when immersed in water, and the impossibility of their sustaining life in it for any lengthened period of time. Experience, however, has taught them, that the ”great deep” is crowded with inhabitants of various sizes, and of vastly different constructions, with modes of life entirely distinct from those which belong to the animals of the land, and with peculiarities of design, equally wonderful with those of any other works which have come from the hand of the Creator. The history of these races, however, must remain for ever, more or less, in a state of darkness, since the depths in which they live, are beyond the power of human exploration, and since the illimitable expansion of their domain places them almost entirely out of the reach of human accessibility.
200. IN STUDYING THE CONFORMATION OF FISHES, we naturally conclude that they are, in every respect, well adapted to the element in which they have their existence. Their shape has a striking resemblance to the lower part of a s.h.i.+p; and there is no doubt that the form of the fish originally suggested the form of the s.h.i.+p. The body is in general slender, gradually diminis.h.i.+ng towards each of its extremities, and flattened on each of its sides. This is precisely the form of the lower part of the hull of a s.h.i.+p; and it enables both the animal and the vessel, with comparative ease, to penetrate and divide the resisting medium for which they have been adapted. The velocity of a s.h.i.+p, however, in sailing before the wind, is by no means to be compared to that of a fish. It is well known that the largest fishes will, with the greatest ease, overtake a s.h.i.+p in full sail, play round it without effort, and shoot ahead of it at pleasure. This arises from their great flexibility, which, to compete with mocks the labours of art, and enables them to migrate thousands of miles in a season, without the slightest indications of languor or fatigue.
201. THE PRINc.i.p.aL INSTRUMENTS EMPLOYED BY FISHES to accelerate their motion, are their air-bladder, fins, and tail. By means of the air-bladder they enlarge or diminish the specific gravity of their bodies. When they wish to sink, they compress the muscles of the abdomen, and eject the air contained in it; by which, their weight, compared with that of the water, is increased, and they consequently descend. On the other hand, when they wish to rise, they relax the compression of the abdominal muscles, when the air-bladder fills and distends, and the body immediately ascends to the surface. How simply, yet how wonderfully, has the Supreme Being adapted certain means to the attainment of certain ends! Those fishes which are dest.i.tute of the air-bladder are heavy in the water, and have no great ”alacrity” in rising. The larger proportion of them remain at the bottom, unless they are so formed as to be able to strike their native element downwards with sufficient force to enable them to ascend. When the air-bladder of a fish is burst, its power of ascending to the surface has for ever pa.s.sed away. From a knowledge of this fact, the fishermen of cod are enabled to preserve them alive for a considerable time in their well-boats. The means they adopt to accomplish this, is to perforate the sound, or air-bladder, with a needle, which disengages the air, when the fishes immediately descend to the bottom of the well, into which they are thrown. Without this operation, it would be impossible to keep the cod under water whilst they had life. In swimming, the _fins_ enable fishes to preserve their upright position, especially those of the belly, which act like two feet. Without those, they would swim with their bellies upward, as it is in their backs that the centre of gravity lies. In ascending and descending, these are likewise of great a.s.sistance, as they contract and expand accordingly. The _tail_ is an instrument of great muscular force, and largely a.s.sists the fish in all its motions. In some instances it acts like the rudder of a s.h.i.+p, and enables it to turn sideways; and when moved from side to side with a quick vibratory motion, fishes are made, in the same manner as the ”screw” propeller makes a steams.h.i.+p, to dart forward with a celerity proportioned to the muscular force with which it is employed.
202. THE BODIES OF FISHES are mostly covered with a kind of h.o.r.n.y scales; but some are almost entirely without them, or have them so minute as to be almost invisible; as is the case with the eel. The object of these is to preserve them from injury by the pressure of the water, or the sudden contact with pebbles, rocks, or sea-weeds. Others, again, are enveloped in a fatty, oleaginous substance, also intended as a defence against the friction of the water; and those in which the scales are small, are supplied with a larger quant.i.ty of slimy matter.
203. THE RESPIRATION OF FISHES is effected by means of those comb-like organs which are placed on each side of the neck, and which are called gills. It is curious to watch the process of breathing as it is performed by the finny tribes. It seems to be so continuous, that it might almost pa.s.s for an ill.u.s.tration of the vexed problem which conceals the secret of perpetual motion. In performing it, they fill their mouths with water, which they drive backwards with a force so great as to open the large flap, to allow it to escape behind. In this operation all, or a great portion, of the air contained in the water, is left among the feather-like processes of the gills, and is carried into the body, there to perform its part in the animal economy. In proof of this, it has been ascertained that, if the water in which fishes are put, is, by any means, denuded of its air, they immediately seek the surface, and begin to gasp for it. Hence, distilled water is to them what a vacuum made by an air-pump, is to most other animals. For this reason, when a fishpond, or other aqueous receptacle in which fishes are kept, is entirely frozen over, it is necessary to make holes in the ice, not so especially for the purpose of feeding them, as for that of giving them air to breathe.
204. THE POSITIONS OF THE TEETH OF FISHES are well calculated to excite our amazement; for, in some cases, these are situated in the jaws, sometimes on the tongue or palate, and sometimes even in the throat.
They are in general sharp-pointed and immovable; but in the carp they are obtuse, and in the pike so easily moved as to seem to have no deeper hold than such as the mere skin can afford. In the herring, the tongue is set with teeth, to enable it the better, it is supposed, to retain its food.
205. ALTHOUGH NATURALISTS HAVE DIVIDED FISHES into two great tribes, the _osseous_ and the _cartilaginous_, yet the distinction is not very precise; for the first have a great deal of cartilage, and the second, at any rate, a portion of calcareous matter in their bones. It may, therefore, be said that the bones of fishes form a kind of intermediate substance between true bones and cartilages. The backbone extends through the whole length of the body, and consists of vertebrae, strong and thick towards the head, but weaker and more slender as it approaches the tail. Each species has a determinate number of vertebrae, which are increased in size in proportion with the body. The ribs are attached to the processes of the vertebrae, and inclose the breast and abdomen. Some kinds, as the rays, have no ribs; whilst others, as the sturgeon and eel, have very short ones. Between the pointed processes of the vertebrae are situated the bones which support the dorsal (back) and the a.n.a.l (below the tail) fins, which are connected with the processes by a ligament. At the breast are the sternum or breastbone, clavicles or collar-bones, and the scapulae or shoulder-blades, on which the pectoral or breast fins are placed. The bones which support the ventral or belly fins are called the _ossa pelvis_. Besides these princ.i.p.al bones, there are often other smaller ones, placed between the muscles to a.s.sist their motion.
206. SOME OF THE ORGANS OF SENSE IN FISHES are supposed to be possessed by them in a high degree, and others much more imperfectly. Of the latter kind are the senses of touch and taste, which are believed to be very slightly developed. On the other hand, those of hearing, seeing, and smelling, are ascertained to be acute, but the first in a lesser degree than both the second and third. Their possession of an auditory organ was long doubted, and even denied by some physiologists; but it has been found placed on the sides of the skull, or in the cavity which contains the brain. It occupies a position entirely distinct and detached from the skull, and, in this respect, differs in the local disposition of the same sense in birds and quadrupeds. In some fishes, as in those of the ray kind, the organ is wholly encompa.s.sed by those parts which contain the cavity of the skull; whilst in the cod and salmon kind it is in the part within the skull. Its structure is, in every way, much more simple than that of the same sense in those animals which live entirely in the air; but there is no doubt that they have the adaptation suitable to their condition. In some genera, as in the rays, the external orifice or ear is very small, and is placed in the upper surface of the head; whilst in others there is no visible external orifice whatever. However perfect the _sight_ of fishes may be, experience has shown that this sense is of much less use to them than that of smelling, in searching for their food. The optic nerves in fishes have this peculiarity,--that they are not confounded with one another in their middle progress between their origin and their orbit.
The one pa.s.ses over the other without any communication; so that the nerve which comes from the left side of the brain goes distinctly to the right eye, and that which comes from the right goes distinctly to the left. In the greater part of them, the eye is covered with the same transparent skin that covers the rest of the head. The object of this arrangement, perhaps, is to defend it from the action of the water, as there are no eyelids. The globe in front is somewhat depressed, and is furnished behind with a muscle, which serves to lengthen or flatten it, according to the necessities of the animal. The crystalline humour, which in quadrupeds is flattened, is, in fishes, nearly globular. The organ of _smelling_ in fishes is large, and is endued, at its entry, with a dilating and contracting power, which is employed as the wants of the animal may require. It is mostly by the acuteness of their smell that fishes are enabled to discover their food; for their tongue is not designed for nice sensation, being of too firm a cartilaginous substance for this purpose.
207. WITH RESPECT TO THE FOOD OF FISHES, this is almost universally found in their own element. They are mostly carnivorous, though they seize upon almost anything that comes in their way: they even devour their own offspring, and manifest a particular predilection for all living creatures. Those, to which Nature has meted out mouths of the greatest capacity, would seem to pursue everything with life, and frequently engage in fierce conflicts with their prey. The animal with the largest mouth is usually the victor; and he has no sooner conquered his foe than he devours him. Innumerable shoals of one species pursue those of another, with a ferocity which draws them from the pole to the equator, through all the varying temperatures and depths of their boundless domain. In these pursuits a scene of universal violence is the result; and many species must have become extinct, had not Nature accurately proportioned the means of escape, the production, and the numbers, to the extent and variety of the danger to which they are exposed. Hence the smaller species are not only more numerous, but more productive than the larger; whilst their instinct leads them in search of food and safety near the sh.o.r.es, where, from the shallowness of the waters, many of their foes are unable to follow them.
208. THE FECUNDITY OF FISHES has been the wonder of every natural philosopher whose attention has been attracted to the subject. They are in general oviparous, or egg-producing; but there are a few, such as the eel and the blenny, which are viviparous, or produce their young alive.
The males have the _milt_ and the females the _roe_; but some individuals, as the sturgeon and the cod tribes, are said to contain both. The greater number deposit their sp.a.w.n in the sand or gravel; but some of those which dwell in the depths of the ocean attach their eggs to sea-weeds. In every instance, however, their fruitfulness far surpa.s.ses that of any other race of animals. According to Lewenhoeck, the cod annually sp.a.w.ns upwards of nine millions of eggs, contained in a single roe. The flounder produces one million; the mackerel above five hundred thousand; a herring of a moderate size at least ten thousand; a carp fourteen inches in length, according to Pet.i.t, contained two hundred and sixty-two thousand two hundred and twenty-four; a perch deposited three hundred and eighty thousand six hundred and forty; and a female sturgeon seven millions six hundred and fifty-three thousand two hundred. The viviparous species are by no means so prolific; yet the blenny brings forth two or three hundred at a time, which commence sporting together round their parent the moment they have come into existence.
209. IN REFERENCE TO THE LONGEVITY OF FISHES, it is affirmed to surpa.s.s that of all other created beings; and it is supposed they are, to a great extent, exempted from the diseases to which the flesh of other animals is heir. In place of suffering from the rigidity of age, which is the cause of the natural decay of those that ”live and move and have their being” on the land, their bodies continue to grow with each succeeding supply of food, and the conduits of life to perform their functions unimpaired. The age of fishes has not been properly ascertained, although it is believed that the most minute of the species has a longer lease of life than man. The mode in which they die has been noted by the Rev. Mr. White, the eminent naturalist of Selbourne. As soon as the fish sickens, the head sinks lower and lower, till the animal, as it were, stands upon it. After this, as it becomes weaker, it loses its poise, till the tail turns over, when it comes to the surface, and floats with its belly upwards. The reason for its floating in this manner is on account of the body being no longer balanced by the fins of the belly, and the broad muscular back preponderating, by its own gravity, over the belly, from this latter being a cavity, and consequently lighter.
210. FISHES ARE EITHER SOLITARY OR GREGARIOUS, and some of them migrate to great distances, and into certain rivers, to deposit their sp.a.w.n. Of sea-fishes, the cod, herring, mackerel, and many others, a.s.semble in immense shoals, and migrate through different tracts of the ocean; but, whether considered in their solitary or gregarious capacity, they are alike wonderful to all who look through Nature up to Nature's G.o.d, and consider, with due humility, yet exalted admiration, the sublime variety, beauty, power, and grandeur of His productions, as manifested in the Creation.
FISH AS AN ARTICLE OF HUMAN FOOD.
211. AS THE NUTRITIVE PROPERTIES OF FISH are deemed inferior to those of what is called butchers' meat, it would appear, from all we can learn, that, in all ages, it has held only a secondary place in the estimation of those who have considered the science of gastronomy as a large element in the happiness of mankind. Among the Jews of old it was very little used, although it seems not to have been entirely interdicted, as Moses prohibited only the use of such as had neither scales nor fins.
The Egyptians, however, made fish an article of diet, notwithstanding that it was rejected by their priests. Egypt, however, is not a country favourable to the production of fish, although we read of the people, when hungry, eating it raw; of epicures among them having dried it in the sun; and of its being salted and preserved, to serve as a repast on days of great solemnity.