428 GUSTAF FR. GOTHLIN 
with this direction of the current, effects of primary inhibition 
occur in the neighborhood of the cathode, I have shown earlier 
in animals which had been operated on so that a short equatorial 
part of a meridional row had been removed beforehand. If, in 
such a case, after the ciliary activity has returned on both halves 
of the row, a centro-oral current of suitable strength is trans- 
mitted through the animal, the oral half of the row stops without 
being drawn in (717, exp. XI), while the aboral part continues to 
strike. 
When a Beroé is put into sea-water containing 0.3 per cent 
of ethyl ether (experiment 6) there is a rapid and strong reduc- 
tion of the frequency of vibration and a number of ciliary waves 
expire.in their course along the meridional row. ‘This I take to be 
an inhibition as a result of chemical stimulation, as I consider it 
at least improbable, that after an influence exerted for less than 
a minute by the weak solution of ether the ability to conduct, 
inherent in the meridional row, should have been extinguished 
by ether that had penetrated in. As we know beforehand about 
the inhibitory conditions that can be produced by mechanical 
means, it seems far more probable that the inhibition in the 
experiments with ether was caused by a ‘sensible’ stimulation of 
the surface layer of the body. As, however, in an animal without 
any central nervous system a stimulation can of course scarcely 
cause any perception, the more general expression receptory 
stimulation seems to be here preferable to sensible. 
The primary inhibition affects the row of swimming plates 
itself and is not a transmitted effect from the more typical ciliary 
epithelium at the sensory pole. Evidence in favor of this is 
found in the result of experiment 10, where the cathodic inhibi- 
tion appears especially distinctly in a piece of a meridional row 
that had been cut out together with a portion of the underlying 
tissue. An additional proof is found in experiment 5. In this 
experiment from an animal 14 mm. long there was removed by 
operation a circular area at the sensory pole with the statolith 
as center and a diameter of 3 mm. When, twenty-four hours 
later, the animal had barely recovered from the acute excitatory 
effects of the operation, it was observed that both touching the 
