8 PHYSICAL CHEMISTRY IN MEDICINE. 



stimuli are of the same kind in the same nerve, this is 

 not at all synonymous with saying: to equal amounts of 

 energy equal reactions. 



At different times and under different conditions we 

 react differently to the same amount of energy, and 

 conversely. Stimuli carrying an amount of energy which 

 normally is not perceived can, as in strychnine poisoning, 

 bring about most powerful effects. The selective be- 

 havior of the nervous end-organs must also be attributed 

 to differences in the stimuli received, which are more 

 than simple quantitative differences in energy. How 

 great is the difference between our sensations of noise 

 and of music! and yet the value of the transmitted energy 

 in the two cases may be the same. 



It would be an easy matter to increase the number 

 of striking examples indefinitely. They all lead to the 

 conclusion that the quality of a natural stimulus plays 

 an important role, as well as the amount of its energy. 

 MULLER himself is inclined to make a qualitative dis- 

 tinction between impulses when he speaks of homogeneous 

 and heterogeneous stimulation of a sense-organ. After 

 all that has been said the assertion seems justified that 

 the new energetic world conception will prove to be 

 scarcely less poor than the mechanical. Did we wish to 

 go, deeper we should have to call the former a purely 

 mechanical one. 



If with this we have to regard as a failure the attempt 

 to solve from the standpoint of energetics DU Bois- 

 REYMOND'S famous riddle of the universe, then of what 

 value are the laws governing energy in the investigation of 

 biological problems? 



If we know from experience or if this leads us to assume 



