INTELLIGENCE AND SPECIAL SENSES. 183 



from it. Mr. Campbell instituted an investigation, which resulted 

 in discovering that the fish, dissatisfied with their new quarters, 

 had leai^ed through the waterfall two feet into the flume, and, swim- 

 ming against the strong current until they reached where the stream 

 crosses under the flume, they had leaped out of the latter to- the 

 stream four feet beneath. 



Upon discovering the method of flight adopted by his finny acrobats, 

 Mr. Campbell prevented further escape by placing a screen at the 

 mouth of the flume. Up to last accounts the dissatisfied fish had 

 discovered no other method of getting into their favorite Sacramento. 

 The questions immediately suggest themselves: How could the fish 

 know that a stream flowed under the flume, the sides of which were 

 considerably above the surface of the water, and if they possessed 

 that knowledge, how were they to know that they were immediately 

 over it? Mr. Redding examined the ground carefully along the 

 flume, and could not discover a single instance of a Trout having 

 jum])ed out at any other place. 



Mr. Redding subsequently communicated to the Forest 

 and Stream the following; solution of the matter: — 



The attention of Prof. E. 1). Cope, the eminent naturalist, hav- 

 ing been called to the above facts, he has given me an explanation 

 Avhich seems entirely satisfactory. He tells me that at the base of 

 every scale of the Trout, at a point where the scale is united with 

 the skin, is a nerve; that all these nerves, from the base of every 

 scale, lead to a large ganglion situated on the center of the forehead 

 of the fish below the eyes ; and that nerves from this ganglion com- 

 municate to the internal ear. These nerves, at the base of each 

 scale, are formed to receive vibrations in water. Any vibration in 

 water reaching^the scales of the fish is thus communicated to the 

 internal ear. If, as was the fact, one of the timbers that suppoited 

 the flume rested in the running water on the ground, the vibrations 

 of this running water on the ground would be carried by this timber 

 to the flume and to the water in it, four feet above, and the ear of 

 the fish would separate and take cognizance of the ditference in the 

 vibrations, as tlie human ear in the air distinguishes the difierence 

 between the voices of friends. 



