44 WHAT IS LIFE 



own laboratory and out of the comparatively few 

 elements, for the greater part four or five only, 

 with which it works. 



Yet all the time that the cell is doing this, all 

 the time that it is breaking up and rebuilding its 

 own substance, whilst it is concocting in its internal 

 manufactory the bye-products of which we are 

 speaking, all this time the cell remains unaltered 

 or unaltered save in immaterial characteristics. 

 It is the same cell, though all its constituents may 

 have been changed. Just so our bodies remain 

 our bodies, though the constituents of which they 

 are composed are constantly altering. One is 

 reminded of the knife which was the same knife 

 though it had had a new handle and new blade or 

 of the more poetical simile of Wordsworth : 



For, backward, Duddon ! as I cast my eyes, 

 I see what was, and is, and will abide ; 

 Still glides the Stream and shall for ever glide ; 

 The Form remains, the Function never dies. 



/ Chemistry then does not raise the veil which hides 

 \ the secret of life, and physics is equally incompetent 

 \ to do so, indeed Lord Kelvin 1 says that " the only 

 ^contribution of dynamics to theoretical biology is 

 jabsolute negation of automatic commencement or 

 /automatic maintenance- of life." 



Movement / Movement, which we have seen to be one of 



1 Properties of Matter, p. 415. 



