Normal water... «. 
Six seconds after trans- 
ference to chloroform 
Six seconds later... 
Six seconds later... 
Six seconds later... 
Six seconds later... ... Wave blocked 
One second ... 
Fig. 18. 
In such experiments, the recovery of the normal 
rate in unpoisoned water is gradual. Taking, for 
instance, the case of a spiral strip in morphia 
(Fig. 19), it will be seen that the original rate 
did not fully return. Some substances, however, 
exert a more marked permanent effect of this kind 
than do weak solutions of morphia. Here, for 
instance, is an experiment with alcohol (see Fig. 20). 
In normal water ... 
Quarter of an hour after 
exposure to mo: pbia ... 
One minute after strength- 
emg dose 2. 2 ck 
Four minutes later, and 
just before blocking of 
Wave... itay se: 
Fifteen seconds later, wave 
continuing blocked 
Immediately after passage 
of wave on restoration 
to normal sea-water ... 
Viave blocked 
Four minutes later 
Quarter of an hour later... 
An hour later 
Onesecond.. s.-- se 
