100 NATURE'S CAMOUFLAGE 



of paper when under water.' 1 The silvery sides of 

 these fish act as mirrors reflecting their environment, 

 and so tending to render them invisible or, at least, 

 inconspicuous. But this protection only avails the fish 

 so long as it maintains its normal posture in the water, 

 with its sides perpendicular. Directly it attempts any 

 antics, the light from above flashes on the burnished 

 surface and the creature becomes conspicuous ; that is 

 the reason why anglers using a minnow or other small 

 fish as bait, or some artificial simulacrum of the same, 

 find it profitable to give it a most unnatural motion by 

 causing it to spin. In all the years that I have been a 

 fisherman (now more in number than it is at all 

 consolatory to contemplate) it never occurred to me to 

 speculate why baits should be made to spin. Dr. Ward 

 has furnished the reason for it. 



He has carried research on the movements and habits 

 of fish into great detail. Having built a study or ob- 

 servatory with glass sides at the bottom of a dry pond, 

 he let the water in round and over it, stocked it with 

 fish of various kinds, and watched and photographed 

 them from his subaqueous lair. Having observed how 

 faithfully the silver sides of dace and roach reflected the 

 water-weeds among which these fish were swimming, 

 he has described this and many other phenomena in 

 fish life in a book which ought to be in every angler's 

 library. Dr. Ward has certainly revealed the signifi- 

 cance of many things with which I have been familiar 

 from boyhood without understanding their significance 



1 Marvels of Fish Life as revealed by the Camera, by Dr. Francis 

 Ward, 1911, p. 24. 



