62 



The Dancing Mouse 



equilibration and orientation. Just what the functions of 

 the organs of the ear sacs are is not certainly known. These 

 facts are of importance when we consider the attempts made 

 by Alexander and Kreidl to correlate the various peculiar- 

 ities of behavior shown by the dancer with the structural 

 facts which their work has revealed. This correlation is 

 indicated schematically below. The physiological facts to 

 be accounted for in terms of structure are presented in the 

 first column, and the anatomical facts which are thought to 

 be explanatory, in the second (2 p. 539). 



FUNCTION 



i Lack of sensitiveness 

 to auditory stimuli. 



2 Defective equilibra- 



tional ability. 



3 Lack of turning diz- 



ziness. 



STRUCTURE 



1 Destruction of the papilla basilaris coch- 



leae, etc. 



2 Diminution of the inferior branch of the 



eighth nerve. 



3 Marked degeneration of the ganglion spi- 



rale. 



4 Destruction of the macula sacculi. 



5 Diminution of the branches and roots of 



the superior and middle branches of the 

 eighth nerve. 



6 Diminution of both ganglia vestibulii and 



of the nerve cells. 



4 Normal reactions to galvanic stimulation. 



Alexander and Kreidl themselves believe that the partial 

 deafness of the dancers (for they admit that the total lack 

 of hearing has not been satisfactorily proved) is due to the 

 defective condition of the cochlea. They account for the 

 imperfect equilibrational ability of the animals by pointing 

 out the structural peculiarities of the sacculus, the vestibular 

 ganglia, and the peripheral nerves. Similarly, the lack of 

 dizziness they suppose to be due to the diminution of the 

 fibers of the nerves which supply the canal organs, the 

 atrophied condition of the vestibular ganglia, and a disturb- 



