PEOPESSOE MATTEIJCCI’S ELECTEO-PHYSIOLOGICAE EESEAECHES. 18::) 
fresh section one of these half-thighs to a third or fourth of its length, and recompose 
the double pile. A differential current arises due to the longest half-thigh. The same 
experiment may be made on two gastrocnemi, which, however, are rarely to be obtainee] 
of equal electromotive power. Two gastrocnemi, as equal as possible, are opposed, 
after b aw rig previously made in each a transverse section towards the tendo Achillis : it 
the two muscles thus prepared are of equal length and taken from the same frog, it is 
almost certain that there will be no differential current. One of these gastrocnemi is 
then reduced to one-half or one-third of its length, the double pile is again formed, and 
the differential current is immediately produced by the longest muscle. 1 ought to 
remark here that these experiments should be made with the usual platinum plates in 
diluted saline solution : in employing amalgamated zinc plates and solution of sulphate 
of zinc, the smallest differences of the electromotive power produce strong and durable 
cuiTents, and hence it is difficult to have the two muscular elements sufficiently equal to 
admit of comparison. 
TVhen, by a fresh section, the length of one of the elements is diminished, as a further 
precaution, an exceedingly thin section should be made hi the other element. If a small 
difference exists between the electromotive power of two elements of equal length, the 
strongest ought to be shortened. 
This experiment is still more strikmg when made on a strip of the long muscle of the 
spine of a livmg rabbit ; the surface and transverse section of this muscle may be touched 
with the plates of the galvanometer so as to have a muscular stratum interposed of either 
8 to 10 or 70 to 80 millimetres. The current in the second case is eight or ten times 
greater than in the former. This experiment recalls that made on the electric organ of the 
Gjunnotus or the Torpedo, by employing strata of various lengths of this organ. I think, 
that, notwithstanding our ignorance as to the form of tlie electromotive element of 
muscles, this proposition leads us to believe that muscular fibre acts as a reunion or 
series of electromotive elements. 
This proposition furnishes a clear explanation of several important facts of muscular 
electricity. The first of these facts is, that a differential current takes place constantly on 
closing the cheuit with the gastrocnemius of a frog united with its half-thigh, the current 
being determined by the gastrocnemius. The experiment succeeds equally, if, instead of 
lea\ing the tendon attached to the gastrocnemius, the latter is cut transversely: in all cases 
it is essential that one of the muscles be longer than the other, so that either the gastro- 
cnemius or the half-thigh may predominate. The same result may be obtained by employ- 
ing a prepared frog reduced to two half-thighs of unequal length attached to a piece of 
the spine. 
This same proposition leads us to explain the fact discovered by M. Du Bois Reymond, 
namely, that a cui’rent is obtained by touching with the plates of the galvanometer 
the central points and the edge of the same transverse section of a large muscle. In 
fact, the central points belong to the longest muscular fibres, and therefore play the same 
part towards the points near the edge of this section belonging to the shortest fibres, as 
the interior of a muscle towards its surface. 
