( 650 ) 
of the metallic pin, projecting about '/, em out of the surrounding 
electrode. A comparison of the results of these experiments with the 
section of the animals used, proved that the strongest action currents 
were obtained when the electrode had reached the spot where the 
nervus acusticus enters into the medulla longata or the adjoining 
part of the medulla oblongata (tuberculum acusticum). The electrodes 
were now united with the string-galvanometer and a compensation 
apparatus (composed according to the method of WERTHEIM SALOMONSON?). 
Thereupon a percussion was fired with a pistolet, and the motion 
of the string simultaneously with a signal, stating the moment of 
the shot, was registered by photography. The oscillation that the 
string showed, appeared to correspond with a current of 4.5 > 10-8 
to 9 10-9 ampere. 
In the various experiments the latent period had a duration of 
0.003—-0.005 seconds. 
The form of the obtained curve variegated in the various experiments ; 
in the same experiment, however, the form remained pretty well 
constant. Without exception a deviation of the string had a two- or 
more-phasical character. Sometimes the phases passed imperceptibly 
into each other (vide fig. II), at other times, a more or less distinct 
pause was perceptible (vide fig. I). Moreover the string showed 
a very slight oscillation with a frequency of 1000—1500 per second. 
3y the control-experiments this oscillating motion was proved not 
to be a physiological phenomenon. The object of these controlling 
experiments was to ascertain in how far the oscillations of the 
galvanometer were not caused by the action-current of the nervus 
acusticus. In the first place it appeared that, with opened current- 
chain, the string showed no oscillation when the shot resounded; the 
above-mentioned slight oscillation did appear with a latent period 
shorter than 0.001 second. Further it appeared that by putting 
various spots of the upper- or lower-brain out of circuit, the string 
showed no oscillation. Motions of the animal were entirely excluded 
by curarisation, the respiration-motions were also suspended. If one 
left the electrodes in situ, and waited, without altering anything in 
the experimental composition, till the animal had died and entirely 
cooled down, even the strongest report could no longer produce any 
oscillation in the string, the resistance in the chain however not 
having increased. 
If an experiment was made when the animal was dead but had 
not yet entirely cooled down, an oscillation was still to be obtained 
though considerably inferior to the one resulting from the living 
1) Werrnzm Satomoyson. Zeitschr. f. Biol. Techn. 1909 Volume I, page 366, 
