* 
184. = Haughton—Mechanical Work done by a Muscle. 
experiments is worthless, as it is based on an empirical peak 
which no meaning, and leads to no further consequenc 
4. t the “Law of Fatigue,’ which explains not an 
ote ‘Nipber s experiments, but so many other experiments 
also, is entitled to be received provisionally as a law of 
animal mechanies, and followed up by deduction to its legiti- 
mate conclusions. 
I shall commence by describing some experiments* of my 
own, in which the muscles were kept in continued action, and 
no interval of rest was allowed. This condition is supposed i in 
the “Law of Fatigue,” and when it is departed from, a cor- 
responding allowance must be made depending on the “ Re- 
freshment” afforded to the muscles during the interval of re- 
se. 
The Sion pe law of muscular action, which I have 
called the “ Law of Fatigue,” is thus expresse ed: 
“When the same ack (or group of muscles) is kept in constant 
action until fatigue sets in, the total work done multiplied by the rate 
of work is constant.” 
I instructed a number of medical students, chosen at random, 
to raise dumb-bells of varying weight, one in each hand, in the 
transverse plane with hands supinated, and raising and lowering 
the weights in equal times regulated by the beat of a pendulum. 
This process was continued until the distress of the fatigue 
produced became intolerable, and the number of times each 
weight was lifted was noted. The students were required to 
experiment, which were— 
1. To keep time with the pendulum. 
2. To raise the weights in the transverse plane. 
3. To supinate the hands. 
a To abstain seeds all bending+ of the knees or spinal 
column. 
5. To lower the weights so as to come down without velocity. 
The 2nd, 3d, and 4th conditions are essential in order to con- 
fine the work done strictly to the same muscles of the shoulder, 
arm, and forearm 
ex perimenter must be carefully watched in order to 
ure the observance of these conditions; for he is impelled, 
petals and unconsciously, by pain, to bring in other 
Iiihof June 816. were communicated by me to the Royal Society on the 
_ + To this defect we gave the name of “slinging.” 
