168 PHYSICAL EXPKESSION. 



by analysis to constitute the " nervous hand," and 

 the probable indication of the conditions analogous 

 to these, we get some kind of explanation of this 

 posture. The drooping wrist is analogous to that 

 seen in hemiplegia ; the hyper-extension of the 

 knuckles and thumb is analogous to conditions 

 such as chorea and subsultus tendinum. This 

 appears a more rational explanation than that first 

 given, and the methods of analysis and analogy give 

 some indication of the physiological significance of 

 the posture. Something very like this posture of 

 the hand is indicated by Dr. Little in his work on 

 deformities, 1853, .as the result of "spastic con- 

 traction." 



My present object is to show that spontaneous 

 postures may be studied with advantage as indica- 

 tions of the conditions of the brain. As to the 

 principles involved in these inquiries. A primary 

 postulate, involved in the following principles, is 

 that 



"If we see some spontaneous nerve-muscular 

 action often repeated in the same and in different 

 subjects, it may be assumed that there is some nerve- 

 centre, or nerve-mechanism, corresponding which 

 can act independently." In any particular instance 

 the assumption of the existence of such a centre or 

 piece of nerve-mechanism -would be strengthened if 

 it could be shown that there are cases of excitation 

 and cases of paralysis of such hypothetical centre. 



The following suggestions are offered as to the 

 methods of determining whether a posture is the out- 

 come of the spontaneous action of the nerve-centres. 



