302 Journal of Comparative Neurology and Psychology. 



is an observation which suggests the importance of the relation 

 of vibration rate to the nature and condition of the transmitting 

 structures. Many individuals failed to react to any moderate- 

 ly intense stimuli within a period of several hours after this 

 operation. The sample series of reactions recorded in Table 

 IV is sufficient comment upon the conclusiveness of the exper- 

 iments so far as the value of these transmitting organs for so- 

 called auditory reaction is in question. 



TABLE IV. 



The Influence of Sounds on Frogs without, Coi.umellae or Tympana. 



3. After the cutting of the eighth nerves reactions to 

 sounds were not obtained. Tests were made with green frogs 

 and bull frogs, but only with the latter could reactions to tact- 

 ual stimuli sufficiently great for the purposes of the investiga- 

 tion be obtained after the operation. Of fifteen frogs used only 

 four reacted regularly to tactual stimuli after being operated, 

 and these gave no sign of reaction to sounds. Typical of the 

 results for those individuals which continued to be responsive 

 to tactual stimuli after the operation is the following series, 

 Table V. The eighth nerves of the bull frog used in the exper- 

 iments of this series were cut May 17; two days later a series of 

 twenty five pairs of reactions was obtained. Experiments 

 were continued at intervals until June 14. The animal was 

 apparently in good condition, the skin wound had healed by 

 the latter date, but auditory reactions were wholly lacking. 



