i GENEKAL PHYSIOLOGY OF MUSCLE 57 



In the first place he investigated the conditions which determine 

 the spontaneous rhythm of contraction in voluntary ergograph 

 work. This rhythm depends essentially upon perception of resist- 

 ance, and not upon the amount of work accomplished by the 

 subject nor his state of fatigue. 



Fio. 37. Treves' new ergograph, in which the weight can be gradually reduced, to obtain a tracing 

 under constant conditions of maximal load and maximal work. Platform (a) to support the 

 forearm, and Mosso's recording apparatus (6) are retained, but the contrivances for fixing the 

 arm and fingers that are not working are discarded. The arrangement for applying the weight 

 is altered. The cord passes over the pulley d, the axis of which ends in a small crank which 

 revolves round the axis with the flexion of the middle finger. The lower part of the apparatus 

 serves to graduate the weight h and keep it maximal by running it along a metal bar one metre 

 long, which moves upon the axis k. It is obvious that the resistance opposed to the flexion of 

 the finger must decrease regularly, in proportion as the weight is farther from the point 100, 

 and nearer the zero at axis 7c. 



The " constant phase " of the work curve was investigated by 

 other authors, and appreciated at its proper value. Some physio- 

 logists, however, while recognising the theoretical accuracy of the 

 isotonic method and Treves' application of the principle of the 

 maximal load, regard the isometric method as more practical and 

 better adapted to the study of voluntary muscular activity. 



