226

THE ORGAN OF SMELL.

found in the head of the fish, and which must be known to every investigator of the gastronomical merits of his game, form part of the mechanical apparatus of hearing.

The external or mechanical apparatus of the organ of smell is a pair of small cavities or chambers, communicating with the aqueous element by means of four apertures, and situated near the extremity of the snout. The two openings of each olfactory chamber are intended to permit a free ingress and egress to the water in which the odorant principles are dissolved. But there exists no contrivance, so far as we know, for maintaining a constant current through the chambers. In this particular, the organ of smell of fishes is greatly inferior to that of higher animals; for in the latter, the olfactory chambers give passage to the greater part of the air which enters the lungs, and are thus enabled to test the quality of all the air received into the chest for respiration. In fishes this power is less requisite, hence the inferiority of construction. The olfactory chambers are lined by a soft membrane, technically a mucous membrane, which is richly supplied with blood-vessels, and is brought into connection with the vital organ by means of a moderately large conducting nerve. The arrangement of this membrane evinces one of those beautiful contrivances which are so frequently met with in the

VITAL APPARATUS OF SMELL.

227

animal machine, and which are intended to provide a large surface within a limited space. In order to increase the extent of this membrane as much as possible, it is thrown into a multitude of minute plaits which radiate from a central point and have a very elegant appearance. From the back of the olfactory chambers there proceed, as we have already stated, two nervous cords, which conduct the impressions received by the mucous membrane to the brain.

The vital apparatus of smell, like that of sight, consists of two round masses or lobes of nervous substance, which occupy the front of the brain, and preside over the manifestation of the olfactive faculty. They are inferior in size to the optic lobes, though often as large as the hemispheres of the brain. We are thus supplied with conclusive evidence of the possession by fishes of a power of smell. The mechanical and the vital portions of the apparatus, with the conducting nerve from the former to the latter, are complete; the only question which requires solution is the degree of the sentient power. The vital apparatus being large would be an argument in favour of a vividness of perception; but the small mechanical portion, and especially the absence of a stream of water through the olfactory chambers, leave the organ imperfect. On these grounds, we should be inclined to give the faculty of smell a position next

228

SENSE OF TASTE IN FISH.

in order to that of hearing, and greatly inferior to that of sight.

Taste is at all times, and in all animals, a modification of common sensation, or the simple sense of touch. Its seat in fishes is probably the whole interior of the mouth, the tongue of these creatures being, as is well known, very small and very imperfectly developed. The observations which we have previously made with regard to sensation and to the vital organs of that faculty --the hemispheres--are applicable here. We cannot give the fish credit for any refinement of taste, and taste, with touch and feeling, must be content to occupy the lowest rank of the nervous

senses.

It is impossible to regard the distribution of the higher faculties of the fish, which is here portrayed, without a sentiment of admiration of the wisdom and goodness of Providence, that has thus restricted the sensations of a large group of creatures, living in an element of danger, and destined to be the prey of the more powerful of their own kind as well as of the other classes of animals. They have the eye to see, the ear to apprehend, and the muscular system to escape danger. They have also a power of smell to discriminate the qualities of the stream which it is their pleasure to seek; while the absence of nicety of taste renders them unheedful of the

PRACTICAL OBSERVATIONS.

229

savour of their food, and an imperfect sensation saves them from the pangs which they otherwise must feel in the grasp of their destroyer.

The angler who will study these observations, and avail himself of the lesson which they convey, will judge how far it is necessary to keep out of the sight of fish, and refrain from making a noise

-to what extent fish suffer torment from the hook, and how far it is useful to employ scented baits to please their palates.

230

NATURAL HISTORY OF SALMON.

CHAPTER X.

THE HABITS OF THE ANGLER'S FISH, AND THE BEST WAYS

THE natural history of this splendid fish, the pride and profit of the great rivers of the British Isles, was nearly unknown fifteen years ago. The greatest natural historians, from the French Lacépède down to our own observant Yarrell, were ignorant of many of the main features of its existence. Until the period alluded to we were nearly all in error with respect to its growth, and we thought the parr a salmon fry. We have now ascertained its growth, and know positively that the parr is not a young salmon of the first year, but a pure trout of the smallest variety, and not unlike a salmon fry in the eighth month of its existence. We also know that up to the beginning of its second year the growth of salmon is