194 
IOWA ACADEMY OF SCIENCE Vpi.. XXVIII, 1921 
PEATE VII • ■ 
24, 25, 26. Three fatigue curves of earthworm muscle finally being 
treated at the end of the fatigue process to weak solutions of ethyl alcohol. 
In • the first two note the gradual increase in height of response up to 
about the eighth stroke, which is a condition found to be constant and 
which we interpret as a sort of “treppe’’, 
28, 29, 30 and 31. Typi-cal modified curves produced by subjecting 
earthworm muscle to the various concentrations of propyl, alcohol there 
stated. Marked similarity is evident in comparing these curves with those 
produced by the ethyl alcohol (see 18, 19, 21 and 27). 
