142 



THE MUSCLE CELLS 







The efliciency of this second phase of muscle work is less than 

 that of the contraction phase, which we saw was 91 per cent. 



Taken together they give a gross efficiency 

 for a complete muscle twitch as 50 per cent. 

 But to this one might apply a correction to 

 take into account the energy expended 

 during muscle rest. 



(3) Rest. During complete inactivity, 

 energy is used for maintaining the muscle 

 FIG. 2.-,. influence of the in a state of preparedness for action, just 



length of a muscle upon tin 1 . . . . 



work done. A muscle one as a liatlOll has to Spend lllOIlCy mamtai 11- 

 inch long (left-hand figure) . . . 



in contracting to half its ing an army in peace time, so the muscle 



This 



P 



cell must always be ready for action. 



length lifts a weight to half 



an inch. A muscle of two 



inches, on the other hand, is , P , . ,. 



capable of lifting the weight IS the third phase OI niUSClllar life - 



to one inch. , , . in- 



(Noel Paton/s Essentials of erroneously termed rest. As we shall see in 



Human Physiology.) , > i j_i i j_i i i_c i 



the sequel, this phase is anything but restlul. 



Again, just as in peace time, the coordinating and integrating 

 machine of empire, the Cabinet, keeps our standing army in a 

 high state of efficiency, so the nervous system constantly sends 

 impulses to the muscles, keeping them ready for instant action. 

 This state of resting readiness may be called the tone of muscle, 

 and is, as indicated above, regulated in part by the nervous 

 system (q.v.). During rest, energy is expended which if sub- 

 tracted from the total energy expended during restitution would 

 raise the efficiency of that phase by about four per cent. 



TABLE XXIII. 

 OXYGEN USED BY CAT'S Gastrocnemius M. (VERZAR, 1912). 



