FISHES; PISCES. 



N lli(^ I"'isiij;s, 1.h(3 last class of vei'tebratijd animals, tli(i cliiel and most obvious 

 (listincf ion lies in their adaptation to a sub-aqueous existence, and their unfitness 

 I'll' )il'(; iijKHi dry land. 



'ili<;re arc ninny V('ilc))ni1(' nnimals winch pass the whole of theii- lives in tlie 

 water, nnd would di(! if transfened to the hiiid, such as tlx* whales and the wliole 

 of tli(i cetacean tribe, an account of which may be found in Vol. 1., page 418. But 

 lliese crcjitures are genei'ally incapnlili- of passing their life beneatli tli<; waters, as 

 theii' lungs ar(i for'iricd ]']k(', those of the ma;iiifialia, ami tlieyai'c foi'(t(!d 1o bi'eathe atmospheric 

 air at the surface (jf the waves. And tliough they would die if Idl ii])()n land, their death 

 would occur fr'om liuiiger and inability to move about in sear(^h of food, and in almost eveiy 

 case a sul)mersion of two continuous houi'S would dj'own the longest breathtid whale; that swims 

 the seas. 



'I'he.Fislies, on tlie contrary, are expressly formed for aquatic existence ; and the beautiful 

 respiratory oi'gans, wliich we know Ijy tlu; popular t(;rm of "gills," are so constructed that 

 tliey can supply suflicient oxygen foi' the aeration of tlie blood. Tli(\v have not tli<; power, as 

 is sometimes imagined, of sepai'ating the oxygen, which, in its combination with certain pro- 

 portions of hydrogen, comitosi' flie i-lement in which they live, but aie abli^ to take advantage 

 of th(i atmos|)hi'ric aii' wliicli is cont^ained in th(! watxir. 



Any r«fa,der wlio liapjK^ns to possess a globe; with gold-Fisli (;an prove, and doubtlessly has 

 proved, tlie truth of this assertion. It often ha-pi)ens t-liat wli(;n the su))])ly of watcu' is insulli- 

 cient,, or the mouth of the v(;ssel too small to p(;rmit tlie iUi' to be a,l)sorb(;(l by the wat;(;r in 

 suflicient volume, the Fish come gasping to the surface, and there swim with ga[)ing mouths, 

 sucking in th(! air with audible gulps. I'lil, if a little water be taken up in a- cup or spoon, and 

 dashed back from a little height, so as to causi; a sharjt sjilash, or, better still, if a syringe be 

 employed for tin; same jtiirjiose, ,so as to <lrive a ([iiantity of atmos])heric air into the water, the 

 Fish soon become contented, th(;ii- anxious restlessness abates, and lliey (piii'tly swim baci<- 

 wai'd and forward, without displaying any nioi'e sigTis of urifsasiness. 



TIk! I'liason tliaX l<lsh(!S die when r(!m<jved fioui the; wab^r, is not be(!aus(! th(; air is poison- 

 ous to them, as some; seem to fancy, but because the delicat;e gill UKimbranes become dry and 

 collai)se against each other, so that the cii'culation of tlu; blood is stopx)ed, and the oxygtm of 

 the a,tmosph(;r(! <',an no lo7igei' aet upon it,. It lu^cessarily follows, that those Fisli whose gills 

 can long(!st i'(!tain moistui(; will live; long(;st f)n dry land, and that those whose gills di'y most 

 rapidly will die tin; soonest,. The licriiiig, for example, when' the dclicnte meml)ianes are not 

 sufliciently guard(Ml from tin; elfects of heat and evaporation, dies almost: iuiiiirdiab-ly it is 

 taken out of the wal.er ; whereas lli<! carp, a, lisli whose gili-covi-is <'aji I'ctain juucli moisture, 

 will survivi- for an astxmishingly long tiuK; upon dry land, and Ihe.-inabas, or climbing perch, 

 is actually able to travel Croiii one jiooi to anol her, ascending Hi'' banks, and e\eii traversing 

 hot and dusty roads. 



The entii'e shape of these (rrea.tures, sul)jected tliough il, be to iiiaiiil'old valuations, is 

 alwa,ys subservient to the great object of i)asslng rapidly through the ])onderous li(|ui(l in 

 which they swim, so as to ena])le them t-o sr^ciii'e tluiir prey "i' avoid their enemies. Kveii in 

 creatures of such dilferent shapes as the sharks, the ettls, the salmon tribe, and the Hat tish, the 



