72 



Art. 1.— K. Fuji 



the "all or none" theoiy. Moreover Oscillogram No. 40 denies 

 these assumptions, for the modal latent periods of the discharges 

 are equal, though the magnitude of the discharges varies very 

 widely. Then the cause of the prolongation must l)e due either to 

 (1) or to (4). The causes (1) and (4) cannot he separated in our 

 former experiments. .1 am, however, inclined to helieve that the 

 cause would he that of (1). 



A'. />.— Oscillogram Xo. 49 is an experiment intended to find the relation between the 

 strength of the stiunilus and the height of the discharge as shown in § V. The latent 

 periods and the modal latent periods are given again in the following table : — 



Table XXVIII. 



(The stimulus of Xo. 1 was ascending by accident.) 

 Here we see that the latent period decreases with the increase of the heiglit of the dis- 

 charge and therefore, when our eyes are restricted to L. P., it seems that the speed of the 

 propagation of the excitation increases with the increase of the height of the stimulus. 

 But when our eyes are turned to the modal latent periods, we see that they give toleraV)ly 

 constant value, and show no regular variations with the increasing .strengths of the stimuli. 

 This shows that the speed of the propagation through the nerve in the normal state does 

 not depend on the strength of the stimulus or on the magnitude of the excitation. Also 

 this experiment shows that the so-called latent period is not suitable to be used as the time 

 of reference for exact Avork. 



IX. Miscellaneous problems. 



Oscillograms No. 53 and No. lOü (Plate XXIX.) represent 

 photographs of spontaneous discharges of a li^•ing hsh. At first we 

 tried to open our shutter by tlie fiist discharge of the fish and to 

 photograph the motion of tbe strips of the oscillograph caused by 



