EXPERIMENTS ON HEARING. 105 



differs very little from the reaction of fishes not operated upon. Since the ears 

 have been eliminated, there is only one conclusion to reach and that is, that 

 blind fishes detect vibrations with a frequency of ioo per second by means of sense- 

 organs in the skin. As stated, I have not been able to eliminate the skin and 

 lateral-line organs, and so can not say definitely whether or not the ears play any 

 part in the reactions of normal blind fishes. Since the reactions are the same, ear 

 or no ear, the part the ear plays in sound-wave perception, if any, is certainly small. 



Using the word "hearing" in the sense in which Kreidl and Parker used it, that 

 is, if we define hearing to be the sensation received through the ear and caused by 

 vibrations either in the air or water, the experiments cited do not enable one to 

 conclude definitely whether the blind fishes hear or not. If they do hear, their 

 power in this direction is very limited. 



The rssults show conclusively that they detect waves of ioo vibrations per 

 second by means of sense-organs in the skin. 



