THE SENSE OF HEARING IN FISHES. 83 



itself seems to be and much has naturally depended upon the mo- 

 mentary phase of the subject. Lang (1903), after an extended ac- 

 count of the relations of the otocysts of invertebrates and the ears 

 of vertebrates to equilibrium, concluded on the basis of Kreidl's 

 experiments that there is no great likelihood that fishes hear, but 

 that experiments should be tried on fishes that have differentiated 

 structures for the production of sounds. Blochmann (1903, p. 

 XCVI.) on similar grounds also doubted if fishes could hear. Hen- 

 sen (1904) reviewed the work of Zenneck (1903) and of Parker 

 (1903a) and concluded from their results that fishes do hear, a 

 conclusion that was justly criticized by Bezold (1904, p. 159), who 

 pointed out that Zenneck's results might be explained on the assump- 

 tion that the skin was stimulated. Somewhat later Zacharias (1906) 

 in a popular article concluded on the basis of the work of Kreidl 

 and of Korner that fishes could not hear and misstated (1906, p. 

 373) entirely the results of Zenneck and of Bigelow which he 

 claimed supported this conclusion. Two years later Korner (1908) 

 declared that conclusive experimental evidence to show that fishes 

 hear had not yet been produced, but he felt that it was not im- 

 possible that they possessed a certain degree of audition. In the 

 same year Edinger (1908) pointed out the relation of sensory reac- 

 tions to central nervous structures and stated on the basis of Piper's 

 work that with fishes it was rather a question of what did they hear 

 than did they hear. Willem (1913, p. 1247), on the basis of the evi- 

 dence already cited, argued in favor of hearing. Watson (1914, p. 

 393), after reviewing the more important statements pro and con on 

 the question of fish hearing, summed the matter up in the sentence: 

 "It seems very difficult to reach any conclusion in the face of such 

 contradictory evidence." 



In attempting to sift what has been thus far advanced on the 

 problem of fish hearing, it is natural to begin with the query of 

 what would constitute hearing in a fish. Both Kreidl (1895) and 

 Lee (1898) have discussed this question in the light of their own 

 experiments. Kreidl (1895, P- 461) has pointed out that it is not in 

 accord with ordinary usage to speak of hearing as any sensory dis- 

 turbance produced in an animal by a vibration propagated through 



