348 Mr Carpenter on the Differences of the Laws 



usual to class under the denomination of vital stimuli not only 

 those which themselves originate in vital actions taking place 

 in the system (as the stimulus communicated by the motor 

 nerves to muscular fibre), but also those which result from the 

 relation of the organism to the external world. Now, if it be 

 true (as we have already attempted to prove, § 22-27), that 

 the actions immediately resulting from this relation are of a 

 physical nature (the conditions only being furnished by vital 

 processes within), we can hardly regard the physical agents 

 light, heat, &c. as vital stimuli, unless we employ the term vital 

 actions in its most comprehensive sense, to indicate all the 

 actions going on in a living organism, which conduce to its pre- 

 servation. On the other hand, the stimulus of the circulating 

 fluid, itself possessed of vital properties (we restrict this term 

 in plants to the descending or elaborated sap), and giving rise 

 to actions of the most strictly vital character, cannot be regarded 

 as itself otherwise than purely vital. 



29. Life, therefore, the sum of all the actions performed by 

 an organized being, is, in the first place, the result of the ope- 

 ration of external agents upon the physical properties of the 

 organs by which the relation between the organism and the 

 external world is maintained. The changes which are the con- 

 sequences of these actions are not identical in their effects with 

 those which we witness in the inorganic universe, because the 

 actions are performed under conditions furnished by the living 

 system with an express tendency to its preservation ; and the 

 products of these actions are of a nature to supply the purely 

 vital properties, which then come into play, with the means of 

 their operation. 



Thus the quantities of carbon, hydrogen, and oxygen, which combined, 

 under ordinary circumstances, would form carbon and water, are united into 

 gum and sugar (the two simplest of proximate principles) in the ascent of 

 the ci-ude sap up the stem of plants ; these principles afford the conditions 

 requisite for the purely vital actions, since out of them are formed, by the 

 process of assimilation, all the complicated variety of vegetable tissues and 

 products. 



Now the manifest tendency of all these processes to a common 

 end, has given rise to the supposition of a presiding power by 

 which the whole are regulated — a " vital principle" — an " or. 

 ganic agent endowed with a faculty little short of intelligence," 



