PHYSICAL EXPKESSIOX. 



the open extended hand and the closed hand ; to 

 say that the hand changes from one posture to the 

 other is one method of describing the movement 

 that has occurred. If movements are expressive, 

 postures must be expressive for the same reasons. 



Postures, like movements, may be taken as in- 

 dices of the action, and of the condition of the 

 central nerve-system, because they are the result of 

 the action of the central nerve-system upon the 

 mnscles. The posture of the hand, or other part, is 

 the result of the balance of the muscles of the part. 

 The position of the bones of the lirnb is the re- 

 sultant of the action of the muscles, and is regu- 

 lated, to a large extent, by the nerve-system. To 

 consider one part only, let us take the hand and 

 forearm. I have hitherto spoken as though only 

 one stimulus could come from the nerve-centres to 

 the muscles of the limb at the same time; ifc is 

 probable that many nerve-centres, or portions of 

 the central mechanism, are together sending stimu- 

 lating currents to the muscles, and that the balance 

 of muscular action is the result of the balance of the 

 action of many nerve-centres. It is, however, not 

 necessary for our purpose to enter upon this dis- 

 cussion as to whether one or many nerve-centres 

 cause a posture ; we can proceed, neglecting this 

 point and making the admissions that the balance 

 of the muscular action which regulates the posture 

 of a limb is the outcome of some portion of the 

 central nerve-mechanism. A posture, when thus 

 produced, is a direct expression of the action of 

 some part of the nerve-mechanism. 



