No. 448.] 



CARASSIUS AURATUS L. 



the inside with a thick layer of cotton wool, which, in turn, was 

 held in place by a sheet of thin cotton cloth to form a deadened 

 floor. On trial, I found that the light entering through tlie glass 

 sides of the aquarium was a source of disturbance to' the fishes. 

 Hence I later made these sides opaque by a cox ei ing of dark 

 paper. My method of producing sound was by an electric tuning 

 fork, which was run by a small storage battery and had a pilch 

 of 100 vibrations per second. This was set up on another table, 

 very close to the first one, but not in contact with it. The toot 

 of this table also stood on many thicknesses of soft paper. The 

 fork itself rested on a deadened support, and was so arranged 

 that after it had been set in vibration, it could readily be mo\ed 

 till its base came in contact with the wooden end of the aciuarinni. 

 This could easily be accomplished without observable jar to the 

 water in the aquarium, and certainly in itself had no effect on 

 the fishes. For when I made the fork, not in vibration, touch 

 the aquarium in the usual way, the fisht^s gave no reaction, 

 although to the vibrating fork they were very responsn e ; I tried 

 this many times. 



With this apparatus, I tested three classes of goldfishes ; (i ) 

 normal ones ; (2) fishes the greater part of whose integument 

 had been made insensitive by cutting the fifth and seventh 

 nerves, the lateral line nerves, and -the spinal cord close to the 

 medulla ; and (3) fishes in which the eighth nerves had l)een 



Goldfishes appear to be much more irre,i;ulai in theii i espouses 

 to sound than some other fishes. When one is first 1*''''*^ 

 in the aquarium, it swims about vigorously, darting from si< e to 

 side in a very restless fashion. This extreme excitabilit\ asts 

 for a considerable time, often an hour ; but finally the hs i 

 becomes more quiet, sinks to the bottom, and remauis nearlx 

 motionless except for an almost incessant movement of the 

 pectoral fins. In a few cases, the fishes lay motionless with 

 these fins folded closely to their sides. If now the tunmg tork 

 was set in vibration, and brought into contact with the wooden 



