HELMHOLTZ IN BERLIN 



force derivable from the total quantity of carbon con- 

 sumed. The remaining four-fifths are devoted to the 

 generation of heat.' 



It will be seen that the doctrine of the conservation 

 of energy was of the highest importance in physiology, 

 as it indicated the road to a thorough investigation of 

 the nutritional changes occurring in living matter. 

 These nutritional changes, if in the direction of the 

 upbuilding of tissues, are also concerned in the storing 

 up of energy, and if, on the contrary, they are asso- 

 ciated with the tearing down of tissue, or, in other 

 words, with chemical decompositions, then energy is 

 set free as mechanical motion, heat, light or elec- 

 tricity. The doctrine also appeared to its early 

 teachers, at all events, fatal to any vitalistic theory. 

 Time, however, has shown that there still are pheno- 

 mena connected with living matter that are outside 

 the range of even this great principle, such as the facts 

 of consciousness. 



57 



