234 A HISTORY OF 



has effectually overturnsd the system of those who supposed that the 

 heat of the stomach was alone a sufficient instrument for digestion 

 The truth seems to be, and some experiments of the skilful Dr. Hun 

 ter seem to evince, that there is a power of animal assimilatioL 

 lodged in the stomach of all creatures, which we can neither describe 

 nor define, converting the substances they swallow into a fluid fitted 

 for their own peculiar support. This is done neither by trituration, 

 nor by warmth, nor by motion, nor by a dissolving fluid, nor by their 

 united efforts, but by some principle in the stomach yet unknown, 

 which acts in a different manner from all kinds of artificial mace- 

 ration. The meat taken into the stomach or maw is often seen, 

 though very near being digested, still to retain its original form, and 

 ready for a total dissolution, while it appears to the eye as yet un- 

 touched by the force of the stomach. This animal power is lodged 

 in the maw of fishes, in a greater degree than in any other creatures; 

 their digestive powers are quick, and their appetites ever are craving. 



Yet though fish are thus hungry, and for ever prowling, no animals 

 can suffer the want of food for so long a time. The gold and silver 

 fish we keep in vases, seem never to want any nourishment at all ; 

 whether it be that they feed on the water-insects, too minute for our 

 observation, or that water alone is a sufficient supply, is not evident; 

 but they are often seen for months without apparent sustenance. 

 Even the pike, the most voracious of fishes, will live in a pond where 

 there is none but himself; and, what is more extraordinary, will' be 

 often found to thrive there. 



Still, however, fish are of all other animals the most voracious and 

 insatiable. Whatever any of them is able to swallow, possessed of 

 life, seems to be considered as the most desirable food. Some that 

 have very small mouths feed upon worms and the spawn of other fish ; 

 others, whose mouths are larger, seek larger prey ; it matters not of 

 what kind, whether of another or their own. Those with the largest 

 mouths pursue almost every thing that has life, and often meet each 

 other in fierce opposition, when the fish with the largest swallow 

 comes off with the victory, and devours its antagonist. 



Thus are they irritated by the continual desire of satisfying their 

 hunger ; and the life of a fish, from the smallest to the greatest, is but 

 one scene of hostility, violence, and evasion. But the smaller fry 

 stand no chance in the unequal combat : and their usual way of es- 

 caping is by swimming into those shallows where the greater are un- 

 able, or too heavy to pursue. There they become invaders, in turn, 

 and live upon the spawn of larger fish, which they find floating upon 

 tin; surface of the water : yet there are dangers attending them in 

 every place. Even in the shallows, the muscle, the oyster, and the 

 scallop, lie in ambush at the bottom, with their shells open, and what- 

 ever little fish inadvertently approaches into contact, they at once 

 close their shells upon him, and devour the imprisoned prey at theii 

 leisure. 



Nor is the pursuit of fishes, like that of terrestrial animals, con 

 fined to a single region, or to one effort : shoals of one species fohow 

 those of another through vast tracts of ocean, from the vicinity of the 

 oole, even down to the equator. Thus the cod, from the banks of 

 Newfoundland, pursues the whiting, which flies before it even to the 



