OF VITAL MOTION. 39 



relation between physical and vital force have been 

 set forth elsewhere, and to these we must refer the 

 student for the other arguments which bear upon this 

 subject. At present, however, we have only to do 

 with physiological facts and considerations ; and these, 

 we may observe, are of such a character as to allow 

 us to suppose an intimate relation between the nervous 

 influence, physically considered, and the ordinary force 

 of matter, so intimate, indeed, that the former may 

 be regarded as a mere modification of the latter, not 

 essential to the functions of vegetables, or of the 

 lowest tribes of animate existence, but superadded in 

 order to intensify the vitality of higher and more 

 favoured creatures. It remains to be seen whether a 

 subsequent examination of the phenomena of vital 

 motions will bear out this conjecture, and the judg- 

 ment must be suspended until the special modes of the 

 operation of force upon the heart and the muscular 

 system generally have been passed in review. 



(b.) Of the organic force^ not of a nervous character^ 

 as an agent in the capillary movements of 

 animal bodies. 



The force here referred to is of a twofold nature : 

 on the one hand, it is the exponent of the changes 

 which constitute the function of nutrition; and on 

 the other, it marks the molecular movements of 

 respiration. 



