70 PHYSICAL EXPRESSION. 



combinations of such movements is represented 

 by 2n; the number of variations in the order of the 

 sequences is without limit, or infinite. 



As an illustration, consider the movements of the 

 five fingers. Let the five digits be respectively re- 

 presented by the letters A, B, C, D, E, and let us 

 consider the combinations in which they move 

 together. There are thirty-two possible combina- 

 tions of such movements, viz., A, B, C, D, E, AB, 

 AC, AD, AE, BC, BD, BE, CD, CE, DE, ABC, 

 ABD, ABE, ACD, ACE, ADE, BCD, BCE, BDE, 

 CDE, ABCD, ACDE, ABCE, ABDE, BCDE, 

 ABCDE, ; but the number of possible variations 

 in the order of sequence of combinations is infinite. 

 These facts illustrate how the number of postures of 

 the hand, i.e. coincident positions of its parts, is 

 finite, but the variations of expression by variation 

 of its movements are infinite. 



Many acts or actions may be described by 

 recording the movements, combinations of move- 

 ments, and sequences of movements. A clear 

 understanding on this point is essential to many 

 of the arguments to be brought forward in this 

 work, especially to understanding the importance 

 attached here to the accurate and detailed study of 

 movements, and the full appreciation of what such 

 studies may teach us as to methods of investigation, 

 and the methods of evolution. Analogies will be 

 made hereafter between combinations and sequences 

 of trophic action, and of movement. 



In order to make our ideas more clear we will take 

 one illustration in some detail, 



