MESSRS. A. WALLER AND A. DE WATTEYILLE ON THE INFLUENCE 
Di agramPIA.. 
Ih a gram HI. JB. 
Tiie accompanying diagram represents the four polar combinations of the testing and polarising 
currents, and the coincidence of their respective kathodic and anodic regions. The signs in large type 
are intended to denote the kathode and anode of the polarising current, and the corresponding electrotonic 
states of the polar and peripolar regions. The signs in small type are intended to apply similarly to the 
testing current; “make,” and “break” here refer to the commencement and cessation of a galvanic 
current, not to make and break induced currents, both of which give rise to make excitation. Figs, a, 6, 
c. d, apply to the electrotonic modifications of the make excitation; figs, e, f to those of the break 
excitation ; the region of excitation is in- each case shaded in the diagram. The combinations are as 
follows:— 
a. Polar excitation coincides with polar katelectrotonus. 
b. Peripolar „ „ peripolar „ 
c. Peripolar „ „ peripolar anelectrotonus. 
d. Polar „ ,, polar „ 
e. Peripolar „ „ peripolar „ 
/. Polar „ „ polar „ 
A. Polar alterations of excitability tested by the break induction current. 
Our first series of experiments were made with the ordinary arrangement of the 
coil (an electromotive force of 2 volts and a resistance of 1 ohm for the primary 
circuit), and gave the following results :— 
1. The effect of the kathode of the break induction current is greater than that of the 
anode. 
Our interpretation of this fact is as follows :—The current consists in an almost 
