MAZE STUDIES WITH THE WHITE RAT 



III. Anosmic Animals 



HARVEY CARR 



University of Chicago 



Anosmic animals were employed to determine the function of 

 olfaction in the environmental alterations described in the first 

 paper. Records were secured from nine anosmic and five 

 blind and anosmic rats. For these animals I am indebted to 

 Miss Vincent. Professor Herri ck made a histological examina- 

 tion of a group of seven of these defective rats. He reported 

 that the operation was successful for two of the anosmic animals 

 and for but one of the five blind and anosmics. From this record 

 it is obvious that no conclusions drawn from the records of 

 defective animals can be trusted without a subsequent histo- 

 logical examination. In our comparisons we shall utilize the 

 data from the three animals of whose defective condition we 

 are certain. Any conclusions from such a small group must 

 necessarily be regarded with suspicion; however, we shall state 

 the facts as they are and indicate their significance. 



ANOSMIC ANIMALS 



The anosmic operation exhibited no apparent deleterious 

 effect upon the vitality of the animals. These animals were 

 kept in the laboratory for nearly a }^ear. Their appetite was 

 undiminished; they looked sleek and well groomed, and the 

 vigor and abundance of their activity was equal to that of 

 normal animals. 



One of the anosmic animals mastered the standard maze in 

 two trials with a total error score of 40. The other rat required 

 21 trials and 127 errors to master the same maze. The average 

 values for a group of 27 normal rats in mastering this maze 

 were 18 trials and 144 errors. Evidently smell is not essential 

 to the mastery of this type of maze. In this connection the 

 construction of this maze must be considered; it was nearly 

 water-tight and covered with closely fitting glass covers. Any 



295 



