490 
MR. F. GOTCH ON THE ELECTROMOTIVE PROPERTIES 
whether mechanically or by the passage through it of a voltaic current. A descending 
direction of current was found to be more favourable than an ascending for the 
production of such an organ response. 
The response of the organ to electrical excitation of its cut nerve thus afforded an 
opportunity for investigating the activity of the organ by using “ nerve-organ ” 
preparations, just as the phenomena of muscular activity had been investigated by 
observations made upon nerve-muscle preparations. It was, however, some years 
before the subject was approached along these lines. 
Eckhard. —In 1858 Eckhard (14) showed that the observation as to the more com¬ 
plete response of the organ to electrical excitation of its cut nerve, when the exciting 
current used was a descending one, held good not only in the case of voltaic currents, 
but also when induction currents were used. He endeavoured with the imperfect 
means at his command to ascertain the character of the organ response, and came to 
the conclusion that its duration was longer than that of an induction shock of much 
the same intensity. 
Marey. —In 1871 a series of experiments was begun by Marey (15) at Naples, 
which were continued at Paris (16); the full results were published in 1877, and the 
conclusions which he arrived at are as follows :— 
(l.) Each excitation of the peripheral end of a cut electrical nerve gives rise in the 
organ to a single shock (flux), just as the similar single excitation of a motor nerve 
gives rise to a single contraction of the muscle which it supplies. 
(2.) The time relations of the “ flux,” as ascertained by the frog signal, show a 
period of inactivity {temps perdu) amounting to about •01" between the excitation 
and the response, and a duration of the response equal to six hundredths of a second. 
(3.) The reflex discharge ( decharge ) of the fish consists of a series of such single 
shocks. These may follow one another with great rapidity, at a rate of one to two 
hundred per second, and under such circumstances must blend just as successive 
muscular contractions fuse when the excitations which produce them occur at intervals 
of time which are less than the duration of the individual contractions. 
(4.) The frequency and strength of the successive shocks which form the powerful 
reflex discharge are affected by variations in temperature, by fatigue, &c. 
The experiments upon the nature of the reflex discharge were particularly 
ingenious ; attention may be drawn to such methods, for instance, as that of leading the 
Torpedo discharge through the primary circuit of an induction apparatus and 
ascertaining by a telephone the state of the secondary coil, and as that of leading the 
discharge through a modified Desprez electro-magnetic signal and recording its 
movements. 
Jolyet. —-With regard to the time relations of the single response, it was shown 
in 1883 by Jolyet (17) that a different interpretation must be given to the interval 
which was found to elapse between the excitation of the nerve and the response of 
the organ, Jolyet found that a large part of the lost time was in reality consumed 
