362 The Natural History of Set borne 



because, when the body is no longer balanced by the fins of 

 the belly, the broad muscular back preponderates by its own 

 gravity, and turns the belly uppermost, as lighter from its 

 being a cavity, and because it contains the swimming-bladders, 

 which contribute to render it buoyant. 



Some that delight in gold and silver fishes have adopted a 

 notion that they need no aliment. True it is that they will 

 subsist for a long time without any apparent food but what 

 they can collect from pure water frequently changed ; yet 

 they must draw some support from animalcula, and other 

 nourishment supplied by the water ; because, though they 

 seem to eat nothing, yet the consequences of eating often 

 drop from them. That they are best pleased with such 

 jejune diet may easily be confuted, since if you toss them 

 crumbs they will seize them with great readiness, not to say 

 greediness ; however, bread should be given sparingly, lest, 

 turning sour, it corrupt the water. They also feed on 

 the water-plant called Lemna (ducks' meat), and also on 

 small fry. 



When they want to move a little, they gently protrude 

 themselves with their Pinna? pectorales ; but it is with their 

 strong muscular tails only that they and all fishes shoot along 

 with such inconceivable rapidity. It has been said that the 

 eyes of fishes are immovable ; but these apparently turn them 

 forward or backward in their sockets as occasions require. 

 They take little notice of a lighted candle, though applied 

 close to their heads, but flounce and seem much frightened 

 by a sudden stroke of the hand against the support whereon 

 the bowl is hung ; especially when they have been motionless, 

 and are perhaps asleep. As fishes have no eye-lids, it is not 

 easy to discern when they are sleeping or not, because their 

 eyes are always open. 



Nothing can be more amusing than a glass bowl containing 

 such fishes ; the double refractions of the glass and water 

 represent them, when moving, in a shifting and changeable 

 variety of dimensions, shades, and colours ; while the two 

 mediums, assisted by the concavo-convex shape of the vessel, 



