ROTATION OF THE HEAD. 187 



movements are often excessive in number in con- 

 ditions of irritability. 



Rotation of the head is often an expression of 

 the mental state. This is specially seen when we 

 contrast rotation with movements of flexion and 

 extension. 



Bulwer * speaks much of head movements as 

 expressive of the states of the mind. 



Rotation of the head is, according to the existing 

 system of our English nerve-muscular organization, 

 an expression of the mental state of "negation," 

 or desire to deny. Flexion and extension express 

 the mental state of acquiescence. 



Now, sometimes we find a child so irritable 

 that the predominant mental (brain) condition is 

 such as to be all negation : the head rotates at 

 all propositions the proposal to go to bed, the 

 proposal to eat, the proposal to walk, etc. The 

 head rotation to all word sounds is a part of the 

 expression of mental irritation or, rather, irritable 

 condition of the mental centres. 



Conversely, a child's state of frequent head 

 flexion and extension to the stimulus of word 

 sounds, indicates the mental state of ready acqui- 

 escence, or good humour. 



It appears, then, that the condition of the brain 

 in the mental state of " ready acquiescence " is one 

 where symmetry of movement prevails, and the 

 mental condition of "negation" is expressed by 

 asymmetrical brain action. 



Certain postures of the Jiead are expressive of 



* Bulwer, op. cit. 



