ADVANCED EXPERIMENTAL PHYSIOLOGY 109 



height of the contraction is 

 measured it will be found that 

 the average height decreases dur- 

 ing the first 180 contractions and 

 then attains a fairly constant 

 level, which represents about 85 

 per cent, of the height of the 

 original contractions . The initial 

 decrease is better marked in 

 Fig. 107, and here the fatigue- 

 level was only about 45 per cent. 



of the original height. The 

 characteristics of an ergographic 

 fatigue-curve, therefore, are an 

 initial fall which takes place dur- 

 ing a variable number of con- 

 tractions, and the attainment of 

 a fairly constant level, which 

 represents varying percentages 

 of the height of the original 

 contractions. This curve strongly 

 suggests that during a series of 



