CHAPTER IV 

 ARMY SURGEON AT POTSDAM : 1843-1848 



As Hussar-Surgeon, Helmholtz was now obliged to forgo 

 the scientific atmosphere in which he had lived, under the 

 inspiration of Johannes Miiller, in constant intercourse with 

 such congenial intellects as his chosen friends du Bois- 

 Reymond and Brucke. His peace-loving, retiring nature was 

 harassed at first by the rude five o'clock awakening, when 

 the bugler blew the reveille at his door to rouse the barracks, 

 and interrupted his slumbers, but he soon grew accustomed 

 to this, and attended with alacrity to his official duties. He 

 arranged a small laboratory for physics and physiology in the 

 barracks, where he was frequently visited by du Bois-Reymond 

 and Brucke, who came out from Berlin to discuss their plans 

 for the future reconstitution of physiology. Though restricted 

 to the most elementary instruments (he constructed an elec- 

 trical machine for himself, which he presented later on to his 

 brother), Helmholtz was always backed up by advice and help 

 from du Bois-Reymond, who, he writes, 'tended me like 

 a mother, to enable me to attain a scientific position/ He 

 plunged at once into his projected investigations on the meta- 

 bolism in muscular activity, and embarked on a series of 

 laborious experiments on the conduction of heat in muscle, and 

 the rate of transmission of the nervous impulse. 



All was well with his parents ; he himself lived a quiet and 

 retired life, wholly immersed in his work. His brother's 

 friends have not yet forgotten the impression made upon them 

 by the young man of twenty-three, who, with a contour of head 

 and a manner inherited from his mother, was distinguished by 

 an expression of absolute calm and intellectuality. All that he 

 * said gave an impression of truth and vigour. His extra- 

 ordinary gift of observation excited the admiration of his 



