234 Proceedings of Boyal Society of Edinburgh. [sess. 
A 
Jm) «j(m+l) 
s i 6 J 
.(«- 1) ) 
( r > 
/, . 
, . . . , ^ m_1) 
> = L w - (1+m) .<J 
An- 1 ) j 
U 
. . . , s (m_1) 
(xx. 4) 
where L stands for % ± a 0 fi a 1}1 .... and the adjngate of L 
is % ± A 0j0 A l9l . . . A n _ ljW _ 1 . As before, no proofs of the theorems 
are given. 
The Electrotonic Variation with Strong Polarising 
Currents. By George N. Stewart, D.Sc., Owens College , 
Manchester. 
(Read January 21, 1889.) 
Let AB (fig. 1) he a piece of nerve interposed in the galvano- 
meter circuit, and C D in the battery circuit. Then, as has long 
been known, on closing the battery circuit, one obtains a current in 
the galvanometer circuit, the direction of which in the nerve is the 
same as that of the polarising current. If, now, stimulation be 
made, say at 1, this current undergoes a negative variation. 
Hermann, who investigated the subject, after Bernstein, was at 
first inclined to explain the negative variation by his law of 
“ polarisation increment.” He assumed that the excitation in 
passing along a polarised nerve undergoes changes in its intensity, 
increasing as it passes through regions under the influence of the 
anode, decreasing as it passes through parts dominated by the 
cathode. 
How, if the current he ascending in the nerve (fig. 1), the 
electrotonic current in AB is also ascending. As B is nearer the 
cathode than A, the excitation will pass B in less intensity than A. 
Accordingly, during tetanus, B may be considered as less negative 
than A. In other words, B will he positive to A, and a current of 
