250 RESEARCHES ON SECONDARY ELECTROMOTIVE 



8 Daniells, the question of secondary resistance was of the less im- 

 portance, as from the first it proved to be unnecessary to exercise 

 any strict supervision of the strength of the stimulating current. 

 Accordingly we did not spend much time in measuring it. In 

 more minute experiments, however, this would occasionally be 

 necessary. 



It must not be thought that our researches are not comparable 

 with those of du'Bois-Reymond because we used relatively much 

 weaker currents. The question here is not of the intensity, 

 but of the density of the current in the muscle, and this is incom- 

 parably greater at the natural ends, especially at the lower end of 

 the sartorius, with the same strength of current, than at the thick 

 portion of the pair of muscles used by du Bois-Reymond ; and 

 this holds good notwithstanding that the sartorius, when the current 

 is led in through the bones, offers a much greater resistance than 

 the pair of muscles does when the current is led in laterally. 

 Hence it is only those experiments conducted by du Bois-Reymond 

 with extraordinarily strong currents which cannot be at once 

 brought into comparison with ours. 



If the care and accuracy with which du Bois-Reymond is wont 

 to conduct his experiments, as well as the acuteness with which he 

 designs and interprets them, be taken into consideration, it will 

 appear surprising that so distinguished an observer should have 

 fallen into so fundamental an error, an error which derives its im- 

 portance from the circumstance that he founds on it his whole 

 theory of nerve and muscle currents. I find the cause of the error 

 mainly in the fact that du Bois-Reymond has not devoted the same 

 thorough study to the mechanical effects of excitation of muscle as 

 he did to the electrical effects. Among other indications this appears 

 from the fact that in 1881 in his work on the researches con- 

 ducted by Dr. Sachs on the Gymnotus, he remarks l cursorily 

 that 'in direct stimulation' (with the electric current) 'contrac- 

 tion commences at all points of the muscle at the same mo- 

 ment.' Quite apart from the researches referring to this matter 

 of Bezold and Engelmann, Biedermann in 1879 brought con- 

 clusive evidence of the fact that it is not so, but that the make- 

 contraction commences at the kathodic, the break-contraction at 



1 Dr. Carl Sachs, Untersuchungen am Zitteraal. Leipzig, 1881, p. 226. 



