400 



ANNALS NEW YORK ACADEMY OF SCIENCES 



a similar high concentration was found in the electric organ of Elec- 

 trophorus electricus. The organs, in one hour, hydrolyze amounts of 

 ACh equivalent to one to five times their own weight. In the larger 

 specimens, the organs have a weight of several kilograms, so that the 



m. 



QCh.E. V^ 

 500- -J9^ 



400+ 15*2 



300--II.4 



200" 7.6 



100 



\ 





\ o 

 \ 

 \ 

 \ 



V 



3.8 





 Head end 



1— 

 10 



20 30-^ cm. 



Caudal end 



FiGUKB 1. Action potential and cholinesterase activity in the electric organ, specimen no. 1. 

 Length of fish, 51 cm. 



Abscissae : distance from the anterior end of the organ in cm. 

 Ordinates: QCh.E. and V/cm. 

 • average QCh.E. from a single piece of tissue. 

 + average QCh.E. values from pieces of the same section. 

 ■ V/cm. 



amount of ACh which may be split in these organs may amount to 

 several kilograms per hour or several milligrams in one-thousandth of 

 a second. These are significant amounts. They make possible the 

 assumption that ACh is directly connected with the action potential and 

 may even generate it, for, in this case, the compound must appear and 

 disappear in milliseconds. If speculation were to be excluded, the only 

 means of removing this compound so rapidly would be by enzymatic 

 action. The high concentration of a specific enzyme appeared partic- 



