CHAPTER V 



HELMHOLTZ IN BERLIN THE CONSERVATION OF 

 ENERGY 



THE researches on muscular motion and on heat 

 led Helmholtz to the study of the great 

 question of the relation to each other of the forces 

 of nature, and especially, and in the first instance, 

 to the relation of these forces to the phenomena of 

 life. What is life ? was a problem often before his 

 mind. Was the living state to be explained by the 

 interplay of the same chemical and physical forces 

 as were at work in the outer world ? Or, was Stahl's 

 view to be accepted, that while the forces were the 

 same in living as in dead matter, they were all 

 subject to a living power or principle which held 

 them together and caused them to work in a particular 

 way till death came, when the physical and chemical 

 forces, now liberated from control, assumed their 

 supremacy and the matter forming the body again 

 returned to the inorganic world ? Was the energy 

 of life continually replenished from some external 

 source ; or was it dependent on the energy of the 

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