No. I.] THE VERTEBRATE EAR. 297 



than through gases, the transmission through the tympano- 

 cochlear chain of bones tends to be more rapid than that 

 through tlie air to the round window ; but it is at the same 

 time counterbalanced somewhat by process of transfer, owing to 

 the lost motion (under certain conditions of the osseous chain), 

 which is a disturbing feature of the process of transmission to 

 the oval window. 



There are three phases in the result of the stimulation of the 

 auditory cell : first, the period of preparation occupied in the 

 propagation of the stimulus through the cell protoplasm, i.e. 

 through the capillo-nuclear and the nucleo-neural filaments of 

 the nerve end cell ; second, the period of excitation during 

 which the filaments are transforming the stimuli received into 

 the nerve stimuli ; and, third, the relaxation period occupied in 

 regaining the normal condition of repose and cell activity, dur- 

 ing which time the accumulated stimuli have passed over into 

 the nerve and left it as before. 



In dealing with the differences of sounds, physiologists are gen- 

 erally agreed that there are three distinct conditions inherent 

 in the physical constitution of sounds which give them their 

 individuality. They are the intensity, Xho. pitch, and the timbre. 



The intensity or force of sound depends upon the amplitude 

 of vibration of the sound wave, and there can be no doubt that 

 this is strictly a differential quality inherent in the physical 

 basis alone. 



The pitch of a sound depends upon the number of whole 

 vibrations (complete aerial undulations alone referred to) exe- 

 cuted by the auditory wave in a given period of time, as Mer- 

 senne discovered in 1636. This, also, is easily proven to be a 

 differential quality of sound entirely dependent upon the physi- 

 cal condition of the aerial undulation. 



The quality, klangfarbe, or timbre of sound, depends, accord- 

 ing to Helmholtz, upon the fonn of the sonjid zuave as caused 

 by either the quality or fonn of the sounding body ; such 

 cjuality or form of the sounding body influencing the timbre of 

 the produced sound by varying the number, pitch, and intensity 

 of the subdivisional tones and harmonies. 



This so-called third property or individual quality of sounds 

 cannot be shown to be due to a third physical condition of the 

 aerial undulations ; on the contrary, it is caused by action of the 



