CHAP. X. §. II. DUEING MUSOULAB CONTRACTION. 197 



in the present chapter. In reference to the fish, 

 also, it must be remembered, that the force evolved 

 bears some relation, according to MATTEucciy, " to 

 the activity of the functions of circulation and of 

 respiration, and of every act of nutrition.'' The 

 apparatus may be a means for the evolution of the 

 force, but not a producer of the force ; and there are 

 some reasons for believing that the electric condition 

 of the blood in the living animal must not be over- 

 looked. 



The question in what way the nerves influence 

 muscular contraction, and have in the develope- 

 ment of the force during muscular contraction, or 

 in the evolution of the force in the fish, I am not 

 now discussing. It is of primary importance to 

 ascertain first of all what does take place. The in- 

 fluence that the nervous system has over these 

 results is a subject for future consideration. 



Sect. II. On the Manifestation of Chemical Action 

 during Muscular Contraction. 



That chemical changes take place in muscles 

 during muscular action, has been inferred from the 

 changes produced in the muscular tissue after 

 violent exercise. Mattedcci^, however, has shewn, 

 that during muscular contraction oxygen is absorbed, 

 and that carbonic acid and nitrogen are evolved. 

 The mode of conducting the experiment is as follows : 



y PhU. Trans. 1847, p. 241. 



2 Philosophical Magazine, June, 1856. 



