60 
James Small . 
An angle which was greater than the angle of balance would 
increase the strength of the action current and the rootlet would 
grow downwards. An angle which was less than the angle of 
balance would result in reversed asymmetric effects from the action 
of the normal polarity current from the main root and the rootlet 
would grow upwards. 
This stable angle is known to be very much the same when the 
root system is inverted. Under these conditions the primary root 
would also be inverted vertically and the current would be similar 
in strength but different in direction of flow in the primary root; it 
would still tend to flow into the secondary root. The action current 
in the secondary root would also be reversed in its relation to the 
morphologically upper and under sides so that the balance would 
again be reached when the secondary root had attained the same 
angle with the vertical as before and, therefore, had the same 
strength of action current. 
It is not necessary to labour this point. Many experiments 
and observational details in connection with secondary roots are 
clearly to be explained along these lines, always keeping in mind the 
point that if the primary root is at an angle to the vertical there will be 
an action current in it, instead of a normal polarity current , which 
may so augment the effects of the action current in the secondary 
root that it (the rootlet) will curve away from instead of towards the 
vertical until it has developed an action current sufficiently strong 
to balance once more the current “ leaking ” from the primary root. 
Considering next the tertiary roots C and D of the secondary 
root B, the electrical conditions are becoming rather complex. 
These tertiary roots arise on all sides of an organ which is no longer 
symmetrical physiologically about its own axis, as in the case of the 
primary root. Although the total effect in the upper and under 
sides may be the same with B at its angle of balance, the asymmetric 
PD is still there. The lateral sides of the secondary root would be 
in similar electrical condition, but that condition would not be the 
the same as upper and under sides. There would be a great 
variety of current strengths in the secondary root which would 
require to be balanced by the action currents of the tertiary roots 
before these could reach a stable angle. Taking C and D as 
examples of such tertiary roots, D would reach its angle of balance 
when the unilateral effects of its action current (PD 1 in Fig. 5) 
were neutralised by the inflowing current (PD *5 in Fig. 5) from B ; 
and C would behave in a similar fashion although in that case the 
angle of balance would be unstable. 
