THE STUDY OP MUSCLE PHYSIOLOGY. 



179 



raise a weighted lever which is attached to a point writing on a 

 cylinder moved by some sort of clock-work. In this case the 

 cylinder is kept stationary during the contraction of the mus- 

 cle ; hence the records appear as straight vertical lines. 



For recording movements of great rapidity, so that the in- 

 tervals between them may be apparent, such an apparatus as is 



Pig. 165.— Spring myograph of Du Bois-Eeymond (after Rosenthal). The arrange- 

 ments for registering varions details are similar to those for peDdnlum myograph 

 (Fig. 173). 



figured here (Fig. 165) answere well, the vibrations of a tuning- 

 fork being written on a blackened glass plate, shot before a chro- 

 nograph by releasing a spring. 



Several records may be made successively by more compli- 

 cated arrangements, as will be explained by another figure later. 



THE APPARATUS USED FOR THE STIMULATION OF 

 MUSCLE. 



It is not only important that there should be accurate and 

 delicate methods of recording muscular contractions, but that 

 there be equally exact methods of applying, regulating, and 

 measuring the stimulus that induces the contraction. 



Fig. 166 gives a representation of the inductorium of Du 

 Bois-Eeymond, by which either a single brief stimulation or 

 a series of such repeated with great regularity and frequency 



