CHAP. xi. The Theory of Striking. 163 



used to be known by the name of Chcetodon rostratus. I suppose he 

 changed his name because he didn't like the stories told about him. 

 Men do say that when he sees a fly in the air, he, to put it nicely, 

 blows a drop of water at it, with such force as to bring said fly down 

 as dead as Julius Caesar. Thereon he improves his opportunities, and 

 puts himself outside said fly. He can make due allowance also for the 

 fly being in motion, and for the wind. Chelmo rostratus may have, in 

 the formation of his mouth, a choke bore, peculiar facilities for forcible 

 and precise expectoration ; but all fish can, and commonly do, perform 

 that interesting operation more or less. The whale takes in a huge 

 gulp of water in its capacious mouth, retains the medusa on which it 

 feeds, and ejects the water in the manner commonly called spouting. 

 Most people will have seen gold fish in an aquarium not only sucking 

 in water, and ejecting it by the gills as mentioned at page 45, but also 

 ejecting it by the mouth when they have taken in any food they do not 

 want to swallow. A grain of rice, for instance, may be seen blown out 

 of the mouth with considerable velocity. Have you never found your 

 worm or your spinning bait blown up your line well clear of the fish's, 

 mouth? How can you account for this except by allowing that the- 

 fish has the power of blowing a thing out of its mouth. If you watch 

 very closely you will see how it is done. The mouth having been 

 opened to suck in either the water the fish is to breathe from, or the 

 food it is to feed on, it is closed again while the gills and gill-covers . 

 are opened to let the water pass out through the gills, while the oxygen 

 is inhaled, and that the food may be swallowed without water. If, 

 when the water has been thus got rid of, it is found that the substance 

 in the mouth is not the food that is desired, but something to be 

 rejected, the mouth is again filled to the full with water by opening it, 

 and then by closing the gills first, and by compression of all the flexible 

 parts about the mouth, and partial closing of the orifice, the water is: 

 violently squirted out. In short, the mouth of a fish is a sort of suction 

 pump capable of working both ways, by alternate dilation and com- 

 pression of the mouth, the gills and gill-covers, and the skin under the 

 chin. If it were not so I do not know how fish could apprehend their 

 food. They have no hand in which to take the food and examine it 

 before putting it in their mouth, as briefly alluded to in the chapter on 

 Fly-fishing for Mahseer. Their mouth is itself their hand, in which they 

 take and examine much that looks like food, but which they are not 



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