ON THE STRUCTURE OF CELLS 143 



liquid and a solid, by the formation of some type 

 or types of liquid crystals and foam-cells such as 

 have been described. 



This cellular structure would be a highly sensitive 

 one and dependent upon many conditions, and may 

 in turn be a factor by which the metabolism is kept 

 up. It is not improbable that it is due in part to 

 the metabolism too, and that the two react upon 

 each other. There can be little doubt, however, 

 that the potentiality of the cell does depend upon 

 the minute structure rather than upon the meta- 

 bolism itself, which it does not appear that physical 

 or chemical laws within our knowledge are sufficient 

 to explain. The directive force we should prefer 

 to ascribe to the minute structure of the cell, than 

 to any mystical and directive force which may be 

 ascribed to the metabolism. It is true, no doubt, 

 that the countless variations and the indefinite 

 potentialities of which it admits are still difficult 

 to explain, on account of the number of atoms which 

 the cell contains, as Clerk Maxwell has pointed out : 

 the number of combinations being limited to a 

 comparatively small number owing to the nature 

 of the compounds formed. By giving a cell a 

 minute cellular structure, however, and by assuming 

 certain definite and permanent or stable motions 

 to be thus associated with such structures, the 

 potentialities may ,be almost indefinitely increased. 



Such structures and specialised modes of motion 

 should be largely dependent upon the metabolism, 

 and yet not be said to form part of them : 



