MOLECULAR FORCES. 171 



meet with phenomena which we cannot deduce from known 

 chemical principles, and which indeed seem to be in direct oppo- 

 sition to them, we must not at once conclude that the laws of 

 affinity are partially or wholly inefficient in these cases; nor 

 should we suppose that there is any marvellous intervention of 

 some force acting with a definite purpose. The chemical force is 

 not destroyed, but the external relations, which control its activity, 

 are altered. Force is obviously nothing more than the expression 

 of the cause of natural laws ; if, therefore, facts do not accord with 

 our laws, we must either have formed a misconception of the ideas 

 of these laws, or, at all events, we must have imperfectly investi- 

 gated the different circumstances under which they were exhibited. 

 The result of forces (which, in a physical sense, is only a short ex- 

 pression for the laws) must necessarily be different under different 

 conditions. 



Albinus* took no superficial view of the organic activity in 

 nature when he established the axiom that the essence of vital force 

 consisted in motion. Even if this expression be far too general 

 for organic action, it cannot be denied that we assume life to exist 

 wherever we perceive a constant alternation of phenomena and 

 incessant changes, induced by the constant motion of the molecules 

 of the organised body, as well as of the organs themselves. 

 Although Albinus overlooked the fact that, on the one hand, some- 

 thing more than this is necessary to vital action, (as we here for 

 the most part consider the grounds and object of motion, often 

 without comprehending its primary origin,) and that, on the other 

 hand, we recognise a perpetual movement in the heavenly bodies 

 without assuming that they are on that account possessed of life, 

 this proposition is to a certain degree correct, when we limit it to 

 the substrata of vital manifestations to organic motion; for we 

 find that wherever matter is endowed with life, its chemical 

 molecules are endowed with incessant motion. 



Metamorphoses are continually developed in the material sub- 

 strata of the living body. Physical forces always strive to main- 

 tain themselves in equilibrium; the matter set in motion by them 

 finds, or, at ail events, may find, its centre of gravity its point of 

 rest. Physical forces continue to act upon matter after it has 

 attained its position of equilibrium, for it is only by opposite 

 actions that the equilibrium exists. A body which is moved by 

 physical laws appears always to tend only towards a state of rest ; 

 inorganic chemistry continues active, and induces motion and 

 metamorphosis until the closest affinities are satisfied. 

 * De natura homiiiis, p. 39. 



