PISCES. 



be even suspended, or their covers kept 

 from moving-, by a string tied round them, 

 the fish would fall into convulsions, and 

 die in a tew minutes. It is said, likewise, 

 that though the branchial apparatus be 

 comprized in a small compass, its sur- 

 face, when fully extended, would occupy 

 many square feet; a fact, that may con- 

 vince the most sceptical, of the number- 

 less convolutions and ramifications in 

 which the included water is elaborated 

 and attenuated, in the course of giving 

 out its air in the respiratory process. 



Fishes have the organs of sense, some 

 of them probably in a very high degree, 

 and others imperfectly ; of the latter kind 

 are the senses of touch and of taste : but 

 the sense of hearing has now been com- 

 pletely ascertained, which was long 

 doubted, and by some physiologists de- 

 nied : the organ is contained in the cavity 

 of the head ; it was discovered by Profes- 

 sor Camper, who remarks, that " fish per- 

 ceive sound, but sound peculiar to the 

 watery element." This organ has been 

 observed and described by Mr. Hunter, 

 in the Philosophical Transactions, who 

 has likewise ascertained that its structure 

 varies in different species. And Dr. 

 Shaw, in his " Introduction to the Natu- 

 ral History of Fishes," Vol. IV. Part I. 

 observes, that "Fishes, particularly of 

 the skate kind, have a bag at some dis- 

 tance behind the eyes, which contains a 

 fluid, and a soft cretaceous substance, and 

 supplies the place of the vestibule and 

 cochlea: there is a nerve distributed up- 

 on it similar to the portio mollis in man : 

 they have semicircular canals, which are 

 filled with a fluid, and communicate with 

 the bag ; they have likewise a meatus ex- 

 ternus, which leads to the internal ear. 

 The cod-fish, and others of the same 

 shape, have an organ of hearing some- 

 what similar to the former, but instead of 

 a soft substance contained in the bag, 

 there is a hard cretaceous stone." From 

 the same work we shall transcribe the 

 observations on the sense of smelling and 

 that of sight. 



" The organ of smelling is la'rge, and 

 the animals have a power of contracting 

 and dilating the entry to it as they have 

 occasion. It seems to be mostly by their 

 acute smell that they discover their food, 

 for their tongue seems not to have been 

 designed for a very nice sensation, being 

 of a pretty firm cartilaginous substance ; 

 and common experience evinces that 

 their sight is not of so much use to them 

 as their smell in searching for their nour- 

 ishment. If you throw a fresh worm into 



the water, a fish shall distinguish it at a 

 considerable distance ; and that this is 

 not done by the eye, is plan from ob- 

 serving, that after the same worm has 

 been a considerable time in the water, 

 and lost its smell, no fishes will come 

 near it ; but if you take out the bait, and 

 make several little incisions into it, so as 

 to let out more of the odoriferous efflu- 

 via, it shall have the same effect as for- 

 merly. Now it is certain, that had the 

 animals discovered this bait with their 

 eyes, they would have come equally to 

 it in both cases. In consequence of their 

 smell being the principal means they 

 have of discovering their food, we may 

 frequently observe them allowing them- 

 selves to be carried down with the stream, 

 that they may ascend again leisurely 

 against the current of the water : thus 

 the odoriferous particles swimming in 

 that medium, being applied more forcibly 

 to their organs of smell, produce a strong- 

 er sensation. 



" The optic nerves in fishes are not con- 

 founded with one another in their mid- 

 dle progress between their origin and 

 the orbit, but the one passes 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 vice versa. Indeed it should 

 seem not to be necessary for the optic 

 nerves of fishes to have the same kind of 

 connection with each other as those of 

 man have ; for their eyes are not placed 

 in the fore-part, but in the sides of the 

 head ; and, consequently, cannot look so 

 conveniently at any object with both 

 eyes at the same time. The crystalline 

 lens in fishes is a complete sphere, and 

 more dense than in terrestrial animals, 

 that the rays of light coming from the 

 water might be sufficiently refracted. As 

 fishes are continually exposed to injuries 

 in the uncertain element in which they 

 reside, and as they are in perpetual dan- 

 ger of becoming a prey to the larger 

 ones, it was necessary that their eyes 

 should never be shut ; and as the cornea 

 is sufficiently washed by the element 

 they live in, they are not provided with 

 palpebrse ; but, as in the current itself the 

 eye must be exposed to several injuries, 

 there was a necessity that it should be 

 sufficiently defended ; which, in effect, 

 it is, by a firm pellucid membrane, seem- 

 ing to be a continuation of the cuticula 

 stretched over it : the epidermis is very 

 proper for this purpose, as being insen- 

 sible, and destitute of vessels, and conse- 

 quently not liable to obstructions, and 



