r.ivsioLiHiv or Mrsru> AM* NKKVKS. 



did not hr-in :it tin- point :, l>u( :i< some lit 1 le di>tance 

 bevond ilii-. :it a. From this it is to he inferred that 

 the contraction of tin- mu>de did u't be^in at the 

 moment ,if irritation, for it i- evident thai the cylinder 

 of tin- mvoMTaph had time to turn from : to a before 

 tl,,. indicator was raised liy tin- contraction of the 

 muscle. A certain time, therefore, elapses before the 

 change produced in the mnsele by irritation re-nlts in 

 contraction. The duration of this tinu \vhich can be 

 acc-nratelv calculated from the length of the >jiace exist- 

 ing Itetweeii ~ and a is about one-hundredth of a 



X a. 



]'!;. IS. Tin: . URVES OF A MI M II-I-IM- \TloN. 



second. Tliis stage is called that of lnt< at i i- 

 for dnriiiLf it the irritation has not yet bee.. me actively 

 eflicicnt in the muscle. From the point a the muscle 

 evidently contracts, as is shown by the rising of the 

 pencil from point a to point b, which is the highest 

 part of the curve described; from that point onward 

 the muscle again lengthens till it resnme< its original 

 length at the point c. The time which elapses bet ween 

 the beu-innin^ o r the contraction and its maximum 

 is called the sta^e of incr.'asin^ energy ; tin' time from 

 this maximum to that of the full re-extension of the 

 mu-elr i- that of the stage of d. Tr. 'a si Hi,'- energy. The 

 whole duration of the muscular pul-at ion from the 

 commencenient of the contraction at till complete 

 ext.-nsioii is a^-ain readied at C, i> from about one-tenth 



to one-sixth of a second. 



