THEIR MODE OF ACTION. 413 



themselves in a new form ; hydrocyanic acid and 

 water being the results of the change. 



Mechanical motion, friction, or agitation, is suffi- 

 cient to cause a new disposition of the constituents 

 of fulminating silver and mercury, that is, to effect 

 another arrangement of their elements, in conse- 

 quence of which, new compounds are formed. 



We know that electricity and heat possess a de- 

 cided influence upon the exercise of chemical affinity ; 

 and that the attractions of substances for one anoth- 

 er are subordinate to numerous causes which change 

 the condition of these substances, by altering the 

 direction of their attractions. In the same manner, 

 therefore, the exercise of chemical ^powers in the 

 living organism is dependent upon the vital principle. 



The power of elements to unite together, and to 

 form peculiar compounds, which are generated in an- 

 imals and vegetables, is chemical affinity | but the 

 cause by which they are prevented from arranging 

 themselves according to the degrees of their natural 

 attractions, — the cause, therefore, by which they are 

 made to assume their peculiar order and form in the 

 body, — is the vital principle. 



After the removal of the cause which forced their 

 union, — that is, after the extinction of life, — most 

 organic atoms retain their condition, form, and na- 

 ture, only by a vis inerticB ; for a great law of nature 

 proves, that matter does not possess the power of 

 spontaneous action. A body in motion loses its mo- 

 tion only when a resistance is opposed to it; and a 

 body at rest cannot be put in motion, or into any 

 action whatever, without the operation of some ex- 

 terior cause. 



The same numerous causes which are opposed to 

 the formation of complex organic molecules, under 

 ordinary circumstances, occasion their decomposition 

 and transformations when the only antagonist power, 

 the vital principle, no longer counteracts the influ- 

 ence of those causes. Contact with air and the most 

 feeble chemical action now effect changes in the com- 



35* 



