BLAZE-CURRENTS OF VEGETABLE TISSUES. 48 
$21. In dealing with animal tissues it is very difficult, if not 
impossible, to get two isoelectric contacts when the electrodes 
are first applied; there is always more or less accidental current, 
by reason of unavoidable injury or from other causes. 
Precisely the same difficulty presents itself in the case of 
vegetable tissues. It is advisable to leave them undisturbed 
in contact with the electrodes for some time before an experi- 
ment is begun; at the end of an hour they may generally be 
considered to have settled down to a stable state. 
$22. The “current of injury," whether accidental or provoked, 
is very considerable ; it gradually subsides, as in the case of 
animal tissues, and can then be renewed by renewed injury. 
The following curve gives the decline of E.M.F. of a pea, led off 
by a freshly-cut and an intact surface. 
Fig. 6.—Pza (Pisum sativum). Decline of Current of Injury after a 
preliminary rise. 
Volt.) — 
0-074 
0:06- 
0-054 
0-054 
0:024 
0:014 
L L 1 1 L i fi 1 
1 1 L 1 1 L 
GO 5 10 i5 20 25 30 
Time, o 1! hour. 
l B 25. At first—z.e. for the first 5 minutes—the current of 
injury increases. This preliminary increase, amounting to 0:005 
to 0010 volt, calls to mind the similar increase recently pointed 
