46 DR. A. D. WALLER ON THE 
there has been no mistake—and it will be an easy matter to 
make sure of this by further trial—we have in our hands a very 
clear and convenient field within which to test a relation between 
physiologieal states and electrical responses. 
$28. Asa rule, the middle peas of a pod give the largest blaze- 
currents; the peas at both ends, being as a rule less developed 
than the others, give smaller effects, if any. We may pick out 
pods more or less completely ripe, and find only the middle peas 
giving eurrents. 
And it is interesting in this connection to note that the rule 
applies to injury-currents as well as to blaze-currents. 
$99. Firra Day.—Young peas have a truly enormous elec- 
trical resistance ; a tenth of a volt through pea and galvanometer 
in series gives a hardly appreciable deflection. This is not merely 
a skin-resistance, for it persists after a slice has been taken off 
each end of the pea; it is a resistance attributable to deficiency 
of electrolytes. 
An adult pea is a much better conductor; an adolescent pea 
is of intermediate conducting value. 
The resistance is greatly reduced in consequence of a single 
electrical shock; and I find reason for believing that the 
alteration is partly due to the multiplication of electrolytes by 
dissociation. 
Alterations of conductivity of old and of young seeds in 
consequence of the passage of induction-currents. 
Full-grown Peas. Young Peas. 
n. After one After nu After one After 
Initial break- tetanisa- | Initial break- tetanis: 
ductivity. res etanisa-| conductivity. Ae etanisa- 
con J- shock. tion. | Y: shock. tion. 
50 70 90 | 2:95 22-5 55 
40 70 70 | 0:5 25 50 
60 70 75 25 22:5 65 
70 75 05 30 55 
45 4hr. later. 
45 1 hr. later. 
65 after tetanis. 
50 4 hr, later. 
60 after tetanis. 
55 4 hr. later. 
65 after tetanis. 
Next day 85 
100 after tetanis. 
95 1 hr. later. 
