70 PHYSIOLOGY OF MlsCU:- ,\M> NERVES, 



this energy during each in>tant in flu- f'>nn of increase 

 in speed \\hich it imparts to its lower end and to the 

 slight weight attached to tin- latter. \Ve niav now 

 raisc tlic quest ion as to tin- amount of force which the 

 muscle \vhcn it has already accomplished part, sav one 

 half, of its contraction, can still evolve. Schwann, who 

 first raided tin- ([iiestion, fastened a muscle to one end 

 of the beam of a scale and attached \\einhts to the 

 other end, but supported this end in such a wav that 

 the muscle was not extended. He was ilius able to 

 determine the force of the muscle in the same way as 

 was described above with the apparatus shown in ti.uf. 20, 

 which depends on exactly the same principle. L. Her- 

 mann repeated SchwannV experiment with this appa- 

 ratus, which is more convenient for the purpose now 

 under discussion. The unweighted, or, at least, \ cry 

 slightly weighted, muscle having been inserted in the 

 apparatus as accurately as possible, so that the platinum 

 point j, just rots on the plate, the muscular force is 

 determined in the way described above (see pp. 65, G7). 

 The vice which carries the urn-de is then lowered to ;i 

 certain definite extent, say 1 mm. If the muscle is 

 then irritated it can become shorter by 1 mm. befoir 



it pulls the lever k ; if it bee es yet shorter it mu.-t 



raise the lever with the weights attach -d to it. The 



weight which it can still lift after it has become shorter 

 by 1 mm. may thus be found. The muscle-A ice is then 

 a^ain lowered and \l\\~- is a^ain and a^ain repeated. 

 A ,-eries of weights-values is thus obtained \\hidi corre- 

 spond with the fon-e of the miiM-le during the different 

 Stages of it- contraction. The roiill .if the e\prriment 



is to show thai the force of t he milx-lr di 'creases, slowlv 



at the commencement . (' contraction, but afterwards 



