HERMANN VON HELMHOLTZ 



vising apparatus by which the phenomena of muscular 

 contraction could be accurately studied. Employing 

 the method of causing a contracting muscle to write 

 its curve on the blackened surface of a revolving 

 cylinder, or on a moving glass plate, a method of 

 observing the time relations of motor phenomena 

 first suggested by Thomas Young, Helmholtz de- 

 vised the well-known myograph, or muscle writer. 

 Schwann had already worked with a rude instrument, 

 in which the contracting muscle was caused to pull on 

 a lever near its fulcrum, and no doubt he was the first 

 to obtain a muscle curve, but Helmholtz improved the 

 instrument by making the lever light, and at the same 

 time rigid, and by other mechanical contrivances. 

 Further, he endeavoured to keep the living muscle in 

 conditions as favourable as possible by covering the 

 part of the apparatus containing the muscle with 

 a glass case, under which pieces of blotting paper, 

 moistened with water, were placed. This ' moist 

 chamber,' as it is technically called, became a space 

 saturated with aqueous vapour, and thus the muscle 

 and nerve were kept in fairly natural conditions, and 

 the effects of cooling and drying were obviated. 



Helmholtz also, in connection with this research, 

 made arrangements by which the nerve or muscle 

 could be stimulated by electric shocks of short dura- 

 tion and of a known intensity. He applied to the 

 well-known induction coil of Du Bois Reymond, 

 designed for physiological purposes,' a modification of 

 36 



