510 IRVING HARDESTY 



applied to the skin close enough together and simultaneously 

 are interpreted as a single stimulus (the sum of the several 

 stimuli) , but if one is given greater intensity, that one is appreci- 

 ated by the brain, while the other images produced by the mix- 

 ture may be neglected. Impulses mediated by given sense organs 

 are distributed to given areas of the cerebral cortex and differ- 

 ences in the development of certain of these cortical areas are 

 claimed in cases of absence or extraordinary development of the 

 function of the corresponding sense organs. Auerbach ('11) 

 found in his study of the brain of Bernhard Grossman, a famous 

 musician whose specialty was the violincello, that, compared 

 with the average type, the surface of the superior temporal 

 gyrus of both sides was considerably greater than normal, with 

 the middle temporal giyus taking part in the enlargement to a 

 slight extent. With proficient musicians, the chief of the differ- 

 entiations in the function of the auditory apparatus are the 

 power of analysis and tone memory-. The supra-marginal gyrus 

 of Crossmann's brain was described as being also extraordinarily 

 developed. Helmholtz himself concluded that the power of 

 analysis depends largel}^ upon 'attention.' 



Whether a note produced vibrations in the artificial tympanic 

 membrane could be easily determined by holding the finger in 

 very delicate contact with the membrane while the note was 

 being sounded. With one of the lower notes used this membrane 

 seemed to manifest a sort of resonance, vibrating with greater 

 excursion than with other notes sounded with approximately 

 the same amplitude. The membrane vibrated apparently as a 

 whole. When the 'ossicle' was removed, its vibrations were 

 even audible. The vibrating diaphragms of the telephone must 

 exercise some form of resonance for it is common experience 

 that certain voices and certain tones are transmitted much more 

 loudly and definitely than others. 



(9) With the notes by which the model was capable of being 

 affected, two further phenomena may be mentioned. (1) Oc- 

 casionally a note would produce a constant buzz in both signal- 

 marker and telephone in one region of the artificial tectorial 

 membrane while in another region the buzzing would manifest 



