490 



FISH. 



medium, being applied more forcibly to their organs 

 of smell, produce a stronger sensation." 



But though we have very little ground for suppos- 

 ing that there is any application of the olfactory 

 nerves of fish which bears much analogy to the sense 

 of smell in animals which live in the air, yet this 

 apparatus is so elaborate, and so constant to its form 

 in the different genera and even species, that it would 

 be very desirable to know more about its use. Not 

 only on account of the light which it would throw 

 upon the physiology of fishes, but because the differ- 

 ence in this apparatus might be made good and per- 

 manent systematic characters. That this apparatus 

 is of very little use, either in directing fishes where to 

 find their food, or how to select it, is highly probable ; 

 and, therefore, in the present state of our knowledge, 

 or rather, we should say, perhaps, of our ignorance, 

 the most rational conclusion is, that those nostrils, 

 which, from their structure and the nature of their 

 internal coating, must be very sensitive in some way 

 or other, teach the fish to avoid water mixed with 

 substances which would be deleterious to its health. 

 In man, and in all those animals which have soft tongues 

 and breathe through the nostrils, there is a very close 

 connection between the senses of smell and taste, 

 especially when the taste is that of an aroma, which 

 affects the palate rather than the tongue, as is proved 

 by the fact, that if a substance having this aroma is 

 taken into the mouth, and the nostrils held closed, it 

 is not only impossible to tell what aroma it is, but 

 there is little or no perception of aroma at all. 



Though the vulgar opinion often is, that fishes do 

 not hear, the contrary is established by many facts. 

 Pond fishes, such as trout and carp, have been trained 

 to come regularly and be fed at the ringing of a din- 

 ner bell, while others have answered to a whistle. It 

 is reported that the Romans, among whom pet fishes 

 were very common in the days of their greatest 

 luxury, could call any one fish by name, and the fish 

 would answer. Perhaps this is going a little too far ; 

 but from the observations which have been made in 

 modern times, it is certain that fishes not only hear, 

 but hear very readily ; and there are some other cir- 

 cumstances which would lead one to conclude that 

 they are susceptible of a good deal of education, and 

 capable of showing considerable attachment. In 

 showery weather, river fishes will often be seen feeding 

 and moving about with the greatest activity, and 

 biting as freely as the most devoted angler could 

 desire ; but if there comes a loud peal of thunder, 

 down goes every fish to the bottom, and the sport is 

 over for some time. So also the discharge of artil- 

 lery, or muskets, or shouting scares the fish ; and, 

 therefore, fishermen are usually silent when shooting 

 their nets. 



In the bony fishes, and also in the cartilaginous 

 ones, which have the gills free, there are no external 

 openings of the ears ; but in those fishes which have 

 fixed gills, there are in the occiput two small openings, 

 sufficient to admit the head of a pin, which lead to 

 the internal ears. In fishes having the gills free, the 

 internal organs of hearing are situated in the sides 

 of the cavity of the cranium, and fixed there by a 

 cellular tissue, consisting of vessels and bony or 

 cartilaginous bridles. In fishes with the gills fixed, 

 those organs are enclosed in a particular cavity 

 formed in the substance of the head. This cavity is 

 situated on the side and posterior part of that which 

 contains the brain, with which it does not communi- 



cate, except by the holes that afford passages for the 

 nerves. The sac exhibits many differences as to size 

 and form in the different species. Besides the ordi- 

 nary viscid fluid, there are some small cretaceous or 

 chalky bodies suspended by a fine nervous tissue. In 

 the osseous fishes these are three in number, and are 

 white and hard, like porcelain. In the cartilaginous 

 fishes with the gills free, these bodies are less nume- 

 rous, and their consistency is seldom greater than that 

 of moistened starch. The use of this peculiar part of 

 the auditory organs is not very well known ; but it is 

 supposed that they communicate to the nerves the 

 vibrations of the water. As the ears of fishes are 

 much more simple in their whole structure, than those 

 of land animals, and as the parts of which they are 

 composed are not easily examined with sufficient 

 accuracy, they cannot well be made grounds of syste- 

 matic arrangement. 



Reproduction of Fishes This, though one of the 

 most general and energetic of all natural operations, 

 is involved in very considerable obscurity ; and human 

 art has not been applied to the increase of the num- 

 bers or the improvement of breeds ; and, indeed, from 

 the rapidity with which all fishes multiply, this does 

 not appear to be absolutely necessary. Fishes are, 

 generally speaking, either oviparous, or producers of 

 eggs which are brought to maturity external of the 

 body of the mother, or they are ovoviviparous, that is 

 producing the eggs in one part of the body, and 

 bringing them to maturity in another, discharging the 

 young alive. In most fishes the two sexes are dis- 

 tinct, and in different individuals ; but in some few 

 instances, it is alleged that they are true hermaphro- 

 dites, or have both sexual energies in the same indivi- 

 duals. This is, however, an obscure part of the subject, 

 liable to many uncertainties ; and, therefore, we shall 

 not enter into any of its details. Leaving them out of 

 the question, we have the two divisions of oviparous 

 and ovoviviparous, or, as they may be more popu- 

 larly termed, fishes which are hatched externally of 

 the mother, and fishes which are hatched internally. 



Of the first, which is by far the most numerous 

 division, and also the most prolific, the whole have 

 free gills, though some of them are bony, and others 

 cartilaginous in the skeleton. The female organs, which 

 are popularly designated roes, are generally double, but 

 sometimes single ; and the corresponding organs of 

 the males, which are properly called milts or whites, 

 are of pretty similar form, though of very different 

 consistency. The roe consists of a vast mass of eggs 

 contained in an apparently very thin membrane, which 

 are at first small, but gradually increase, and are 

 large and very distinct at the time when they are 

 excluded from the body. The milt contains a thickish 

 fluid, which merely increases in quantity, so as to 

 arrive at its greatest bulk when the ova or eggs of the 

 female are in a condition for being deposited. 



It is for the purpose of bringing this substance to 

 maturity, that so many fishes seek the warmer parts 

 of the waters at certain seasons of the year ; and it is 

 for the purpose of depositing their spawn, that the 

 greater number of our shoaling fishes, which are at 

 other times in the deep water, or discursive through 

 the seas, come upon the coasts. The places to which 

 various species of fishes resort for these purposes, the 

 mode in which the eggs and milts, or spawn as the two 

 jointly are called, are deposited, and the substances to 

 which they are attached for the purposes of stability or 

 protection, are, however, so numerous, that it is impos- 



