Physiology. — "A contribution to the physiology of the electrical 

 oryan of Torpedo" By Prof. F. J. J. Buytendmk. (Coinmiiiii- 

 oated l\y Prof. G. van Runbkrk). 



(Communicated at tlie meeting of April 29, 1922). 



Ill the winter of 1911 1 had Ihe opportunitv to investigate the 

 fmietioii of the electrical organ of Torpedo in the Zoological Station 

 of Naples. The aim of part of this research was to study the 

 magnitude and character of its disciiarges under different circum- 

 stances. For this purpose a string-galvanometer (large type of Edel- 

 mann) was available at Naples and with this apparatus I made many 

 records. From these records and from test-records of the apparatus 

 it appeared, that tlie string-gahanometer is not the most suitable 

 instrument for the registration of the disciiarges of the organ of 

 Torpedo which reach their maximum within 0,002 — 0,003 sec. This 

 does not astonish us in connection with the investigations of Gaktkn ^). 

 For this reason 1 intended to continue this research with an appa- 

 ratus more suitable for this pui-pose (oscillographion, Fuji'), string- 

 electrometer, Ckemer'). However, as circumstances prevented me 

 from carrying out this plan, I now communicate the results of my 

 researcli. 



Marey, Schönlein and Gotch *) have already observed that the reflex- 

 discharge of the electric ray has a rhythmical character. In many 

 records 1 found that as a rule many dischai-ges succeed each other, 



Fig. 1. Reflex-discharge in Torpedo after mechanical stimulation. 

 Test-record 4 volt. Time '/so sec. 



1) Garten. Abb. d. Kgl. Sacbs. Ges. d. Wiss. 1899. 



2) Fuji. Journ. of Ibe College of Science Univers. Tokio 1914, Vol. 37. 



3) Ceemer. Sitz. Ber. Pbysiol. Geselscb. Berlin 1912. Mediz. Klinik 1912, N". 42. 

 *) S. Garten. Handb. d. Vergl. Physiol. 3e Bd. 2e H., p. 177. 



9 

 Proceedings Royal Acad. Amsterdam. Vol. XXV. 



