PRIMARY INHIBITION OF CILIARY MOVEMENT 417 
4h. 17 m. In a row with mean frequency the number of 
waves is found to be 20/25 sec. = 48 per minute. Tube elec- 
trodes are lowered into the cuvette. 
Experiments with closure of a longitudinal oro-central current. 
4h. 26m. With a current of density 0.53 m.amp./cm.? there 
is no perceptible inhibition. 
4h.28m. With a current of density 1.07 m.amp./cm.? there 
is no perceptible inhibition. 
4h. 30 m. One row shows, when there is no current, a fre- 
quency of 20/21.5 sec. = 56 per minute. After a current of den- 
sity 1.67 m.amp./cm.? has been closed no wave is seen, during an 
observation time of 22 seconds, in the aboral part of the row, but 
notwithstanding there are observed a couple of waves in the 
most oral part of the row. 
4h. 33m. Without any current there is in one row a wave- 
frequency of 20/14 sec. = 86 per minute. After a current of 
density 2.83 m.amp./cem.? is closed total inhibition ensues.. 
In the aboral part of the animal all the swimming plates are 
still for 50 seconds, but then occasional waves occur on a few 
rows. 
4h.36m. The animal is observed with the naked eye, while 
a current of the same density as before is closed. It is then 
observed that after a total inhibition affecting all the swimming 
plates for 10 seconds, while the current is kept closed, ciliary 
waves begin to appear after 10 seconds on one row, after 20 
seconds on another and after 60 seconds on a third. These waves 
begin a short distance down on the row at about half-way between 
its aboral origin and its equatorial point. No motion is visible 
nearer to the sensory pole. 
During the period from 4 h. 37 m. till 4h. 48 m. it is observed 
that as a rule the animal shows a rapid ciliary activity but that it 
continues now and then to stop the ciliary movements entirely. 
The inhibitory apparatus is thus intact. 
4h.49m. The animal is transferred to another cuvette, in 
which to the sea-water has been added atropin sulphate in the 
proportion of 2:10000.. Temperature in the cuvette, 18.2°C. 
