498 
MR. F. GOTCH ON THE ELECTROMOTIVE PROPERTIES 
From the preceding experiments we are led to conclude that after cutting the 
organ an electromotive change occurs in the columns bordering on the cut, of such a 
character that the dorsal ends of the columns are positive to the ventral ends. The 
change is evidently that observed by du Bois-Reymond in strips of tissue, and called 
by him the organ-current. It subsides rapidly at first, and then more and more 
slowly, and is in this respect analogous to the demarcation-current produced by injury 
in muscle and nerve. 
In the latter tissues a prolonged electromotive change is produced when a portion 
of the tissue is injured by mechanical, thermal, or chemical means; this effect slowly 
subsides ; it is increased when the tissue in the neighbourhood of the injury is warmed, 
diminished when that part is cooled. In both muscle and nerve the demarcation- 
current is the sum of changes produced by the injury in a number of electromotive 
elements, and its amount is therefore dependent upon the number of muscle fibres or 
nerves which are involved in this injury. The effective injury for its production 
in these tissues is thus a section which shall cut at right angles to their length as 
many fibres as possible. 
Now, in the organ of the Torpedo the electromotive elements, plates, and nerves are 
disposed at right angles to the length of the framework which encloses them, and 
which constitutes a column. 
A proceeding analogous to that of making a transverse section of the nerve fibres 
of a nerve trunk is thus carried out upon the organ columns when an incision is made 
through the organ parallel to the columns. Such an incision must cut at right 
angles to their length a large number of plates and nerves; this should be followed 
by an electromotive change which expresses the sum of the local changes occurring in 
the immediate neighbourhood of the cut. 
This is what I conceive to be the meaning of the organ-current. Like all 
“ demarcation” currents, it is the expression of a protracted state of excitation of the 
still living tissue in the neighbourhood of the injury. The corresponding electro¬ 
motive change must manifest itself as all the excitatory phenomena of the Torpedo 
manifest themselves, namely, as a current passing through the column from the 
ventral to the dorsal surface. 
In support of this assertion we will now pass to experiments as to the effect of 
local warming of an incised surface. 
From a small Torpedo 13 centims. long by 9 centims. wide a slice of organ was cut, 
which was then divided up into three blocks. Each block comprised the whole length of 
the columns which remained covered by skin at their dorsal and ventral ends. Each 
was 2 mins, wide and 3 nuns, thick, and thus consisted of several unimpaired columns 
surrounded by columns which had been cut through parallel to their length. These 
cylinders of tissue were now examined, the skin ends being led off by kaolin cushions. 
The first cylinder, examined five minutes after its preparation, showed a difference 
of potential = + '0045 It., subsiding rapidly to -f- ’0034 R., and then more slowly. 
