160 APPENDIX IT. 



man, Helmholtz estimates that not more than ith of 

 the actual energy developed in the body can be 

 made to appear as external work. The experiments 

 of Haidenhain, however, show that, under favourable 

 circumstances, a muscle may be made to yield in 

 the shape of mechanical work as much as one-half 

 of the actual energy developed within it, the re- 

 mainder taking the form of heat. Taking then this 

 highest estimate of the proportion of mechanical 

 work capable of being got out of actual energy, it 

 becomes necessary to multiply by 2 the above 

 numbers representing the ascertainable work per- 

 formed, in order to express the actual energy involved 

 in the production of that work. We then get the 

 following comparison of the actual energy capable 

 of being developed by the amount of muscle con- 

 sumed, with the actual energy necessary for the 

 performance of the work executed in the ascent of 

 the Faulhorn : 



Thus, taking the average of the two experiments, 

 it is evident that scarcely th of the actual energy 

 required for the work performed could be obtained from 

 the amount of muscle consumed. 



Gthly. Interpreted in the same way, previous 

 experiments of a like kind prove the same thing, 



