Structural Peculiarities and Behavior 71 



taken too seriously, for by his theory of space perception and 

 of a sixth sense he was unduly biased in favor of the struc- 

 tural peculiarities described by Rawitz. Nevertheless, his 

 discussion is not without interest, for the way in which he 

 succeeded in making every structural fact which Rawitz sug- 

 gested fit into his theories and help to account for the func- 

 tional peculiarities which he had himself observed, is extremely 

 clever and indicates a splendid scientific imagination. 



To sum up : All the facts of behavior and physiology which 

 have been established lead us to expect certain marked struc- 

 tural differences between the dancer and the common mouse. 

 The bizarre movements, lack of equilibrational ability, and 

 the nervous shaking of the head suggest the presence of 

 peculiar conditions in the semicircular canals or their sense 

 organs; and the lack of sensitiveness to sounds indicates 

 defects in the cochlea. Yet, strange as it may seem to those 

 who are not familiar with the difficulties of the study of the 

 minute structure of these organs, no structural conditions 

 have been discovered which account satisfactorily for the 

 dancer's peculiarities of behavior. That the ear is unusual 

 in form is highly probable, since three of the four investiga- 

 tors who have studied it carefully agree that it differs more 

 or less markedly from that of the common mouse. But, on 

 the other hand, the serious lack of agreement in their several 

 descriptions of the conditions which they observed renders 

 their results utterly inconclusive and extremely unsatisfactory. 

 The status of our knowledge of the structure of the central 

 nervous system is even less satisfactory, if possible, than that 

 of our knowledge of those portions of the peripheral nervous 

 system which would naturally be supposed to have to do with 

 such functional peculiarities as the dancer exhibits. So 

 far as I have been able to learn, no investigator has carefully 

 examined the brain and spinal cord in comparison with those 



