38 



EXPERIMENTAL PHYSIOLOGY 



to give the tracing of fig. 38, where we note that 



these oscillations are 

 much less. To 

 diminish the effects 

 of acceleration we 

 must always aim at 

 employingrecording 

 levers of as small a 

 mass as is compati- 

 ble with the neces- 

 sary rigidity. The 

 lever used for fig. 38 

 was much lighter 

 than that used for 

 fig. 41. 



It is, however, 

 necessary for many 

 experiments to 

 study the contrac- 

 tion when the mus- 

 cle is loaded. We 

 have seen that if 

 we apply the load 

 directly under the 

 muscle, acceleration 

 must come into play 

 with the result that 

 the tension does not 

 remain constant, but 

 during the earliest 

 part of the contrac- 

 tion period is in- 

 creased, and during 

 the later part and 

 most of the period 

 of relaxation it is 

 below that of the 

 weight, and at the 

 end of relaxation it 

 rapidly rises, and 

 after a few oscilla- 

 tions ultimately 

 reaches the initial 

 tension. The part 



