THE SENSE OF HEARING IN FISHES. 77 



mentation that the American catfish, Amiiirus nebulosus, regularly 

 took fright when he whistled. On testing this fish further Maier 

 was completely convinced that it responded to sounds. It was, 

 however, the only fish of those examined by him that so responded. 



Bernoulli (1910) tested fresh-water fishes in their natural sur- 

 roundings with the sounds given out by a submerged electric bell 

 and with shrill whistling. Three species {Salmo fario, Anguilla 

 vulgaris, and Luciopcrca sandra) were subjected to the sound from 

 the bell and two {Salmo fario and Thymallus vulgaris) to whis- 

 tling. In no instance was there a response. 



Haempel (1911) also used the sound from a submerged electric 

 bell and a shrill whistle as stimiuli for fishes. Five species of fresh- 

 water fishes were tested (Cyprinus carpio, Scardiniiis erythroph- 

 thalmus, Gobio fluviatilis, Trulta fario, and the Zwergwelse^= 

 Amiurus). None of these fishes reacted to the sounds used except 

 Amiunts which regularly responded to both the sound of the bell 

 and to whistling. On removing the ears from a specimen of 

 Amiunts and allowing the wounds to heal, the animal lost all re- 

 sponse to the sounds employed. Haempel (1911, p. 325), there- 

 fore, concluded that while members of the Salmonidse and Cypri- 

 nidze cannot be said to hear, the Siluridse and particularly Amiurus 

 must be admitted to possess powers of hearing. 



In consequence of the results of Maier (1909) and of Haempel 

 (1911) Korner (1916) was led to investigate hearing in Amiurus. 

 This fish was subjected to various kinds of shrill whistling, includ- 

 ing that from an automobile whistle, to a series of musical tones, 

 to the notes of a scale sung by the human voice, and to the sounds 

 from a " cri-cri." To none of these stimuli was there the slightest 

 response. Korner (191 6, p. 263) was unable to explain his nega- 

 tive results with Amiurus as compared with the positive outcome 

 of the tests made on the same fish by Maier (1909) and by Haempel 

 (1911). 



The papers that have thus far been summarized support in 

 general the conclusion that most fishes do not hear. Those that 

 follow have yielded evidence of an opposite kind. Piper (1906a, 

 1906&) prepared the ear and the eighth nerve of the pike and of 



