142 



THE MUSCLE CELLS 



The efficiency of this second phase of muscle work is less thar 

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

 Taken together they give a gross efficiency 

 ( ) y \ / \ for a complete muscle twitch as 50 per cent 



But to this one might apply a correction tc 

 take into account the energy expended 

 during muscle rest. 



(3) Rest. During complete inactivity 

 energy is used for maintaining the muscle 

 FIG. 25. influence of the in a state of preparedness for action, iusl 



length of a muscle, upon the , . 



work done. A muscle one as a nation has to spend money maintain 



inch long (left-hand figure) . 



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



length lifts a weight to half 



an inch. A muscle of two cell must always be ready tor action. 1 1m 



inches, on the other hand, is ., . i i i P i !/> 



capable of lifting the weight is the third phase of muscular life 



to one inch. , , A t_ 11 



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



Human Physiology.) ,-, -, .-, . , . .1 i p i 



the sequel, this phase is anything but resttul 



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

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

 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 woulc 

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



TABLE XXIII. 



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



