ALCOHOI.S AND FATIGUE PROCESSES 
171 
est concentration tried, 3.7 vol. per cent, the muscle fatigues uni- 
formly and quickly, but after the completion of the second contrac- 
tion phase it goes into relaxation rapidly so that the resulting 
curve (Fig. 17) is in this respect exceptional to the other concen- 
trations of this alcohol, but comparable to the lower strengths of 
ethyl alcohol noted above. 
Butyl alcohol. — Strong and saturated solutions of this alcohol 
give curves (Figs. 18 and 19, PI. Ill) which are typical and which 
are comparable with similar strengths of propyl alcohol just des- 
cribed. Contracture starts almost immediately on the muscle’s 
being stimulated and is maintained at a remarkably uniform rate 
with almost no relaxation phase at the end of the fatigue cycle. 
The three solutions of weaker strength of this alcohol which 
were tried, namely, 4.7 (Fig. 22), 3.4 (Fig. 21) and 1..7 (Fig. 
20) vol. per cent, gave typical curves similar to each other and 
to the weakest concentrations of ethyl and propyl alcohols. This 
would seem to indicate that the differences in range as computed 
were not sufficient to give differences in effective . physiological 
responses which were sufficient to analyze. All tend to have a 
definite comparable initial relaxation phase as indicated by the 
drop in the writing point in the early progress of the curve, and 
all on the completion of the second contracture phase have a rather 
rapid onset of secondary relaxation as indicated by the abrupt 
descent at the terminal portion of the curves. It is very evident, 
too, that these concentrations have an exhaustive stimulating 
effect since fatigue once started proceeds rapidly, and that in this 
respect they are more potent than the three low grades of either 
methyl and ethyl alcohols and even more so than comparable 
toxic strengths of its predecessor propyl alcohol. 
Amyl alcohol. — In strong and saturated concentrations amyl 
alcohol gives curves similar to those of comparable strengths of 
both propyl and butyl alcohols and decidedly in contrast to com- 
parable strengths of methyl and ethyl alcohols. With strong amyl 
alcohol the first contracture phase is produced immediately when 
the muscle is stimulated as is shown in figure 23, and proceeds 
gradually to produce the secondary contracture (see Fig. 13 for 
comparison with propyl alcohol). The plateau of secondary con- 
tracture is with this alcohol more pronounced and extensive than 
is the case with propyl or butyl alcohols. The three lower concen- 
trations used, 1.1, 0.5 and 0.2 vol. per cent, strange to say, give 
curves (Figs. 25, 26 and 27, respectively) which in all details 
more closely resemble the three comparable strengths of methyl 
