ii2 INTRODUCTION TO GENERAL PHYSIOLOGY 



fundamental note itself is accompanied by a large number of other 

 rates' of vibration due to the subdivision of the string into various 

 numbers of parts of shorter length, each giving rise to a note 

 of higher pitch, in some multiple of the fundamental. The presence 

 of these harmonics, as they are sometimes called, can be detected 

 by the use of appropriate resonators. The form of the air waves 

 resulting from the combination of these harmonics with the 

 fundamental note is usually represented by compound sine curves, 

 such as those of Fig. 5. But it is to be remembered that although 

 such curves correctly represent the movements i of particles in 

 transverse vibration, or the ether waves of light}, they are only 

 diagrams of the changes of pressure in sound wa^es. The height 

 of the ordinates of such curves is to be taken as/representing the 

 series of pressures at a given point. One may/ realise, to some 

 extent, the kind of thing that would correspond to the upper curve 

 of Fig. 5, by imagining what would be shown py a manometer. 

 The pressure would rise quickly and fall gradually. Whereas 

 in the lower curve it would rise slowly and fall quickly. In some 

 other cases it would, after having fallen somewhat, rise again and 

 then continue the fall, and so on. Looking atjsuch curves it is 

 difficult to believe that they are composed of a Dumber of simple 

 vibrations, and that an appropriate resonator can pick out any one 

 from amongst them. 



It might be supposed that the comparison of two such wave 

 forms as those of Fig. 5 would serve as a test of the correctness of 

 the resonator theory of the cochlea. If this theory be correct, 

 there should be no difference in quality if the phase relation is 

 altered, because the two resonators are independent, and each picks 

 up its own rate of vibration regardless of the other. If, on the 

 other hand, the basilar membrane vibrates, as a whole, in a wave 

 form corresponding to that of the sound, and transmits this by the 

 nerves to the brain to be analysed there, then phase difference 

 should be appreciated. Unfortunately, there is no agreement on 

 the fact. But it seems rather doubtful whether the methods used 

 by those who state that phase difference is of importance were such 

 as to exclude other effects on the components of the complex waves. 



The Eye Receptor for Light 



The eye may be said to be the most accurately adjusted of all 

 our receptor organs. It is adapted by its movements and great 

 sensibility to give us more correct and valuable information about 

 things that are happening, both near and at a distance, than any 

 other organ of sense. 



As previously mentioned, light consists of transverse waves in 



