222 
THOMPSON YATES LABORATORIES REPORT 
valid and sound as applied to Du Bois Reymond's idea, loses all interest when applied 
to Grunhagen's. 
Du Bois Reymond's experiment was as follows : — The muscle was torn into 
minute strips so as to obtain longitudinal fragments containing only a few muscle fibres. 
One of these longitudinal strips was laid upon one electrode; another was placed 
so as with its transverse section to touch the longitudinal surface of the first, and 
with its own longitudinal surface upon another electrode. The normal ' current of 
rest ' of the second strip was observed to be present. 
The idea which Du Bois Reymond tested by this experiment was the possible 
presence of two heterogeneous structures in the muscle fibre, two physical structures 
capable of causing an electrical current, when in contact, as, for instance, do copper 
and zinc. Such a probability was forced upon him by the histological distinction 
between the sarcolemma and the contents of the muscle fibre. The results of the 
experiment given above were taken, and, it is obvious, legitimately so, as conclusive 
evidence against the possibility; for, as Du Bois Reymond said then, the structures 
were arranged as follows : — 
First Fibre 
Sarcolemma. Contents. Sarcolemma. 
Second Fibre 
Contents. Sarcolemma. 
The arrangement is thus symmetrical, and is incapable of giving rise to an 
electrical current if the assumption tested were true, as, for instance, would also be the 
case with the similar arrangement — 
Copper. Zinc. Copper. Zinc. Copper. 
Since the experiment did, however, result in the exhibition of the usual current, the 
assumption and this method of regarding the arrangement of structures in the 
experiment were necessarily excluded. 
But this test is meaningless when applied to Grunhagen's theory, as was done 
by Hermann, for the structures as seen in its light are as follows : — 
First Fibre 
Nutritive fluid. Membrane. Contents. 
Second Fibre 
Nutritive fluid. Membrane. Contents. Membrane. Nutritive fluid. 
