MUSCLES, NERVES, AND ELECTRICAL ORGANS. 



215 



o".2 

 10" 



+ 90 

 76 



-90 

 98 



arises from positive polarisation, and that the preponderance of this 

 polarisation in the direction of the shock is not merely accidental, 

 follows further from the fact that when the current passes trans- 

 versely nothing of the kind is observed. 



Strip from the back cut transversely. 20 Groves. 



+ 90 



76 sc 



-90 

 92; 104 



r, I indicate right and left. Through the thickness of the organ 

 from the outer skin to the internal fascia 40 Groves with o"-2 time 

 of closure only produced 25 in both directions. The so-called Haut- 

 sckwarte produced with 30 Groves and the same time of closure, only 

 2 in both directions. 



From a piece of the organ I removed the skin and fascia ; 

 it continued to give secondary actions, though in a somewhat 

 irregular manner, which was not surprising considering that it had 

 lost all regularity of structure. No secondary electromotive action 

 could be elicited from the fin, either with 30 Groves and a time 

 of closure of o-"2, or with 30 Groves and 20", or with 20 Groves 

 and 15". Certainly this was the day after that on which the fish 

 was found dead ; but this would not account for the inactivity of 

 the fin, if it were polarisable like the electrical organ, seeing that 

 the latter still showed vigorous electromotive action. In fact, when 

 kept in a damp chamber at a temperature of little over oC. the 

 organ retained, like a dying nerve (Sect. 18), a small quantity of 

 polarisability for an astonishingly long time, as is shown in the 

 following table, in which the primary action is recorded only 

 exceptionally, as a second observer was not always at hand. 



XXX. 



Jan. t 13, 14, 15, 16, 17, 18, 1858. 



S -90 -90 + 3 -90 -45 





8+90 

 iP - 



+ 60 



I 



r-i 4 



\+ 4 8 



-6 



1 8, 

 -8 

 41" 



38 



A strip perpendicular to the lateral line gave, with a current passed 

 transversely through it on the i6th of Jan., 55 in one direction, 

 and in the other 59. 



Thus on the sixth day after the death of the fish traces of 

 polarisation were still present, according to the same law as for fresh 

 organs. They finally disappeared with the properties of life, the 



