3 62 THE POPULAR SCIENCE MONTHLY. 



that medicine is the proper road to that goal. A medical student, 

 then, Du Bois-Reymond became, and as such, a pupil, and soon after 

 an assistant of the great anatomist and physiologist, John Miiller. 



The connection with Miiller decided, as it were, his fate. Humboldt 

 at that time received a copy of Matteucci's " Essai sur les Phenomenes 

 electriques des Animaux," and communicated it to Miiller. Miiller, 

 knowing that Du Bois-Reymond possessed a share of physical and 

 mathematical knowledge very unusual in a student of physiology, 

 thought him qualified to take in hand the investigation of animal elec- 

 tricity, in which Matteucci had made but a poor advance since Nobili's 

 discovery of the so-called current of the frog. Thus it happened that, 

 in the spring of 1841, Du Bois-Reymond undertook to elucidate the 

 problem proposed to science by Nobili, and for nearly forty years he 

 has not ceased to work upon this subject, which, in his hands, and those 

 of his numerous pupils, has marvelously expanded, so as to become one 

 of the most important branches of physiology. 



Du Bois-Reymond, after having in 1842 printed a short account of 

 his first results, went on working patiently for seven years, and then 

 published his celebrated book, "Researches in Animal Electricity" 

 (Berlin, 2 vols., 1848-'49). This work, besides a complete history of 

 what had previously been done upon the subject, contains an immense 

 number of experiments, made after methods, and with the aid of ap- 

 paratus, for the most part entirely new, invented by Du Bois-Reymond 

 himself. In substance, the book is devoted to the exposition of his 

 discoveries of the muscular and of the nervous current, of their law, 

 and of the variations they undergo when the muscles and nerves are 

 thrown into action. 



To understand the importance of these discoveries, it must be borne 

 in mind that, long before Du Bois-Reymond, in fact since the middle of 

 last century, innumerable attempts had been made to observe electrical 

 phenomena during the contraction of the muscle. They had all failed. 

 Du Bois-Reymond, at the outset, perceived that one of the reasons of 

 these failures was the transient nature of the contraction, and he in- 

 vented the method of tetanizing the muscles in order to increase the 

 duration of the contraction, and thereby facilitate the observation of 

 what takes place in that state. He was thus fortunate enough to 

 detect electrical phenomena concomitant with the act of contraction, 

 and he even taught how to deflect the magnetic needle of the galva- 

 nometer by the voluntary contraction of the muscles in living man, or, as 

 it were, by our will. The correctness of these facts having been doubt- 

 ed by MM. Despretz and Becquerel, of the Academie des Sciences, Du 

 Bois-Reymond, in 1850, went to Paris with his apparatus, and trium- 

 phantly proved the truth of his statements. 



As to the nerve, up to the date of Du Bois-Reymond's researches, 

 no material change had ever been observed during its activity. In this 

 case, too, a great many fruitless attempts had been made to discover 



