52 



niYSIOLOGY OF MUSCLES AND NERVES. 



determined. The myograph of Helmholtz depends on 

 this principle. Originally it consisted of a glass cylin- 



FiG. 17. Myograpit of Helmholtz. 



(Oue quai'tLT natural size.) 



4 



der which rotated rapidly on its own axis. The appa- 

 ratus has, however, since undergone many alterations. 



