OF THE ELECTRICAL ORGxYN OF TORPEDO MARMORATA. 
493 
armature. From the curve traced, by this signal when the organ response is led through 
it he deduces the character of the curve, developing rapidly and subsiding more slowly. 
A more accurate curve might be obtained by photographing the movement of a 
quick capillary electrometer, but even this could not be considered satisfactory unless 
a series of galvanometric readings corresponding to known time intervals had been 
also made. The great improvement in the construction of galvanometers renders 
this last method still more satisfactory. 
A series of galvanometric readings may not, owing to the short closures necessi¬ 
tated by the rheotome, give a complete account of an electromotive change, but as far 
as it goes it is perfectly trustworthy. It was, therefore, with the object of making 
such series of galvanometric readings that the electromotive phenomena of the 
response were re-inyestigated in the present research. 
The organ-current .—The uncertain and meagre character of our knowledge with 
respect to the organ-current is much more pronounced. We are able to predict with 
certainty that, if jn muscular or nervous tissue a violent local molecular change is 
effected by mechanical injury or by the application of heat or chemical reagents, 
a change such that there is on the one side complete death of tissue, and on the 
other side tissue of which the vitality is unimpaired—the former state shading into 
the latter—then this will manifest itself by an electromotive effect in the neighbour¬ 
hood of the injury. This electromotive change is always of such a character that the 
impaired tissue becomes strongly negative to the unimpaired tissue. 
But with regard to the possibility of producing such electromotive phenomena in 
the electrical organ we know nothing. The great importance of experiments upon 
this subject is sufficiently obvious, and the first part of the present research is, 
therefore, devoted to the results of such experiments. The remarkable character of 
the discoveries of du Bois-Reymond, already referred to, warranted re-investigation, 
and a large number of experiments have been made with reference to these. 
The results embodied in the present preliminary account may, therefore, be grouped 
under three heads : — 
I. Experiments relating to the organ-current. 
II. Experiments relating to the time relations of the excitatory change produced 
in the organ by excitation of its nerve. 
III. Experiments connected with the passage of electrical currents through the 
organ. 
All the experiments were carried out in the months of December, 1886, and 
January, 1887. Through the kindness of the Sociffte Scientifique d’Arcachon, several 
rooms in the Zoological Station at Arcachon were placed at the disposal of Dr. Burdon 
Sanderson and myself. The methods and lines of work had to be decided upon in 
England, as it was necessary to take out all the essential apparatus from the Oxford 
Physiological Laboratory. 
It thus necessarily happened that in some instances work had to be given up whilst 
still incomplete, as some essential piece of apparatus was wanting. 
