SKETCH OF PROFESSOR DU BOIS-REYMOND. 363 



some electrical phenomenon connected "with that state. Du Bois-Rey- 

 mond constructed with his own hands a galvanometer of 24,000 coils, 

 by far the most sensitive ever made up to that time, and by its means 

 succeeded in disclosing an electrical phenomenon in the tetanized nerve, 

 which, for certain reasons we cannot here explain, he styled the nega- 

 tive variation of the nerve-current. In point of fact, he transmuted 

 into a deflection of the galvanometer that molecular change in the nerve 

 which, had it reached the muscles, would have convulsed them, and 

 which, had it reached the brain, would have caused pain. He also de- 

 cided the long-vexed question whether the nervous fibres conduct only 

 in one direction, or in both, by showing that the negative variation is 

 equally well transmitted in a motor nerve in the centripetal, and in a 

 sensitive nerve in the centrifugal direction. 



Soon after the publication of his " Researches," Du Bois-Reymoncl, 

 then thirty years old, was elected a member of the Royal Academy of 

 Sciences of Berlin. As already stated, he has ever since pursued and 

 extended his investigations ; but it is impossible, in the compass of this 

 brief notice, more fully to detail their results. Moreover, those of our 

 readers who may feel interested in the subject will find a conscientious 

 expose of most of Du Bois-Reymond's papers in the book of one of our 

 countrymen, of whose talents science has been robbed by a premature 

 death Mr. Charles E. Morgan, author of " Electro-Physiology and 

 Therapeutics " (New York, William Wood & Co., 1868). These re- 

 sults will also be found in Prof. Rosenthal's German treatise on the 

 " Physiology of Muscles and Nerves," contributed to the " Interna- 

 tional Scientific Series," and soon to be published in this country. Du 

 Bois-Reymond's papers have also been collected in two volumes, under 

 the title " Gesammelte Abhandlungen zur allgemeinen Muskel- und 

 Nervenphysik " (Leipsic, Veit & Co., 187o-'77). 



Several of Du Bois-Reymond's papers bear merely upon electricity, 

 without reference to physiology. We will only mention his experi- 

 mental and theoretical researches on the aperiodic state of the magnetic 

 needle induced, under certain circumstances, by high dampening pow- 

 ers ; these researches are of the greatest practical importance. Du 

 Bois-Reymond also showed, contrary to what Berzelius and Liebig had 

 stated, that the substance of muscles when at rest is neutral, or slight- 

 ly alkaline, becoming acid only after death, when rigor mortis sets in, 

 but that also in the act of contraction acid is evolved. 



In 1858 John Muller died, and Du Bois-Reymond was appointed in 

 his place Professor of Physiology in ordinary, and Director of the Physi- 

 ological Laboratory at the University of Berlin. In this position he has 

 exercised a considerable influence on the progress of physiological study 

 in Germany. Many of the professors of physiology at the other Ger- 

 man universities have been his pupils ; and this influence has been in- 

 creased by the friendship which has always connected him closely with 

 his fellow-students Brucke, Helmholtz, and Ludwig all of them physi- 



