276 HEKMANN VON HELMHOLTZ : 



Stahl's theory ascribed to every living body the nature 

 of a perpetuum mobile. I was tolerably well acquainted 

 with the controversies on this latter subject. In my 

 school days I had heard it discussed by my father and 

 our mathematical teachers, and while still a pupil of 

 the Friedrich Wilhelms Institut I had helped in the 

 library, and in my spare moments had looked through 

 the works of Daniell, Bernouilli, D'Alembert, and other 

 mathematicians of the last century. I thus came 

 upon the question, { What relations must exist be- 

 tween the various kinds of natural forces for a per- 

 petual motion to be possible?' and the further one, 

 c Do those relations actually exist ? ' In my essay, 

 c On the Conservation of Force/ my aim was merely to 

 give a critical investigation and arrangement of the 

 facts for the benefit of physiologists. 



I should have been quite prepared if the experts 

 had ultimately said, ' We know all that. What is this 

 young doctor thinking about, in considering himself 

 called upon to explain it all to us so fully ?' But, to my 

 astonishment, the physical authorities with whom I 

 came in contact took up the matter quite differently. 

 They were inclined to deny the correctness of the law, 

 and in the eager contest in which they were engaged 

 against Hegel's Natural Philosophy were disposed to 

 declare my essay to be a fantastical speculation. 

 Jacobi, the mathematician, who recognised the con- 



