o PHYSICAL CHEMISTRY /// MEDICINE. 



widest recognition, has already proclaimed the complete 

 triumph of the energetische Weltanschauung (energetic 

 conception of natural phenomena). 



According to this conception transformations in energy 

 constitute the kernel of all phenomena in nature, and 

 their quantitative determination furnishes at the same 

 time a complete insight into the course of things. 



If this is true, then the reaction of the sensory nerves 

 is also always a consequence of changes in energy and 

 these become therefore the means by which sensory 

 experience is obtained. 



An attempt will be made in the following paragraphs 

 to show that a purely energetic conception of natural 

 phenomena conceals all the dangers of a too extensive 

 generalization, as it leads to a one-sided development 

 of our point of view with all its threatening consequences. 



Do transformations in energy really constitute the whole 

 or even the nucleus o) the changes that go on, in and 

 about us? Do we really react only in proportion to the 

 amount of difference in energy ? 



Transformations in energy are in fact constant accom- 

 paniments of all changes in nature, and we could scarcely 

 possess a simpler picture of nature than one in which all 

 differences represent only differences in the amount of 

 of energy. In reality, however, it is only one side of all 

 natural phenomena that we are able to include in the 

 energetic principle, for only for the value of the mechanical 

 work performed in all changes does the law of its inde- 

 structibility hold. The energetic analysis of a phe- 

 nomenon is, however, so little exhaustive that in physical 

 realms, such as that of electricity for example, we are 

 unable to answer the question of the nature of electrical 



