12 Mr. Home's Lecture 



each, is not peculiar to this part. A remarkable instance of it 

 appears in the rapid movements of the -fingers, in performing 

 several actions, and particularly in playing on a musical instru- 

 ment. In all such rapid motions, the fingers are bent to a 

 certain degree by the long muscles that lie upon the fore-arm, 

 to the tendons of which a set of smaller muscles are attached, 

 called lumbricales. These last are unable to produce any effect 

 on the fingers, till elongated in consequence of the action of 

 the long muscles in bending the other joints ; the lumbricales 

 then become capable of bending the fingers a little more, and 

 of acting with great rapidity. It is a curious circumstance, 

 that a similar application of muscles should be employed to fit 

 the fingers to produce a quick succession of sounds, and to 

 enable the ear to be impressed by them. 



From the explanation given of the adjustment of the mem- 

 brana tympani, the difference between a musical ear and one 

 which is too imperfect to distinguish the different notes in 

 music, will appear to arise entirely from the greater or less nicety 

 with which the muscle of the malleus renders the membrane 

 capable of being truly adjusted. If the tension be perfect, all 

 the variations produced by the action of the radiated muscle 

 will be equally correct, and the ear truly musical ; but, if the 

 first adjustment is imperfect, although the actions of the ra- 

 diated muscle may still produce infinite variations, none of them 

 will be correct : the effect, in this respect, will be similar to that 

 produced by playing upon a musical instrument which is not in 

 tune. The hearing of articulate sounds requires less nicety in 

 the adjustment, than of inarticulate or musical ones : an ear 

 may therefore be able to perceive the one, although it is not 

 fitted to receive distinct perceptions from the other. 



