1 82 THE METHOD OF DARWIN. 



though perfect in structure, were apparently 

 functionless; they were not known to give off 

 any electrical discharge. 



Darwin left the problem unsolved except for 

 the suggestions he offered, and it still remains 

 unsolved in part. Among the reasons for this 

 state of the subject are these : that the habits of 

 the electric fishes have been but little known, 

 that the powers of the electric organs are but lit- 

 tle understood, and that both are very difficult 

 to investigate. 



The present state of the subject is made 

 interesting by the recent studies of Professor 

 Fritsch. 1 From the first the electric organs 

 have been regarded as modified muscular tissue. 

 They occupy the place of what in other fishes 

 is common muscle. The Pacinian law of the 

 direction of the current in electric organs -is 

 that at the instant of the shock the side of the 

 electric plate on which the nerve enters is neg- 

 ative, and the opposite side positive; and in 

 this important respect such of them as are of 

 undoubted muscular origin agree with the com- 

 mon muscular tissue and its electrical phenom- 

 ena. Fritsch' s interesting recent studies on 



1 Gustav Fritsch, Archiv fiir Anatomic und Physiologic, 

 Supplement Band, 1892; Nature, Jan. 19, 1893, Vo1 - XLVII. 

 p. 271. 



