I] OF MATTER AND ENERGY 11 



depend on various things, from simple imbibition of water to the 

 complicated results of the chemistry of nutrition, it deserves to 

 be studied in relation to form, whether it proceed by simple 

 increase of size without obvious alteration of form, or whether it 

 so proceed as to bring about a gradual change of form and the 

 slow development of a more or less complicated structure. 



In the Newtonian language of elementary physics, force is 

 recognised by its action in producing or in changing motion, or 

 in preventing change of motion or in maintaining rest. When we 

 deal with matter in the concrete, force does not, strictly speaking, 

 enter into the question, for force, unlike matter, has no independent 

 objective existence. It is energy in its various forms, known or 

 unknown, that acts upon matter. But when we abstract our 

 thoughts from the material to its form, or from the thing moved 

 to its motions, when we deal with the subjective conceptions of 

 form, or movement, or the movements that change of form implies, 

 then force is the appropriate term for our conception of the causes 

 by which these forms and changes of form are brought about. 

 When we use the term force, we use it, as the physicist always 

 does, for the sake of brevity, using a symbol for the magnitude 

 and direction of an action in reference to the symbol or diagram 

 of a material thing. It is a term as subjective and symbolic as 

 form itself, and so is appropriately to be used in connection 

 therewith. 



The form, then, of any portion of matter, whether it be living 

 or dead, and the changes of form that are apparent in its movements 

 and in its growth, may in all cases ahke be described as due to 

 the action of force. In short, the form of an object is a "diagram 

 of forces," in this sense, at least, that from it we can judge of or 

 deduce the forces that are acting or have acted upon it: in this 

 strict and particular sense, it is a diagram, — in the case of a solid, 

 of the forces that have been impressed upon it when its conformation 

 was produced, together with those that enable it to retain its 

 conformation ; in the case of a Hquid (or of a gas) of the forces that 

 ^re for the moment acting on it to restrain or balance its own 

 inherent mobihty. In an organism, great or small, it is not 

 merely the nature of the ynotions of the living substance that we 

 must interpret in terms of force (according to kinetics), but also 



