Miscellanies. 387 
MISCELLANIES. 
FOREIGN AND DOMESTIC. 
1. On the Hypothesis of Electric Currents in the Nerves; by M. Mar- 
tTEucci.—Never having been able, in our former experiments, to establish, 
by aid of the galvanometer, the existence of electric currents in the brain, 
the spinal cord, or in the nerves of the dog, the rabbit, and the frog, we 
wished to make a new trial on an animal of large stature, (the horse,) 
hoping by this means to place ourselves in the most favorable condition for 
researches of this kind. 
The galvanometer which we employed in these new experiments was 
constructed by Rumkorff, and was extremely sensible; the conducting 
wire, making two thousand five hundred convolutions, was furnished at 
each of its extremities with a platinum plate, fixed on an ivory handle, 
and so varnished as to leave only a square centimetre of its surface ex- 
posed. The needle made one oscillation in seventy seconds. 
Before applying the two platinum plates to the nervous parts, they were 
immersed in spring-water for a very long time, and until the signs of the 
current, which are always observed at the first immersion, had completely 
disappeared. 
These precautions having been taken, and the live horse having been 
thrown down upon a table, its sciatic nerve was insulated from the neigh- 
boring muscles (by means of varnished silk) for a length of thirty or forty 
centimétres, (upwards of one foot,) was carefully wiped, and left in com- 
munication with the cerebro-spinal axis. 
After being well assured that the needle constantly remained at zero, 
although either one or other of the platinum plates was removed from 
the water and alternately reimmersed, the plates were placed in contact, 
first with the surface of the sciatic, then, after the neurilemma had been 
removed, with different points of this voluminous nerve. 
The interval of deviation, namely, the distance comprised between the 
two plates, being at first 3 or 4 cent., the needle sometimes remained at 
zero, and at other times deviated several degrees, soon returning to zero. 
This interval having been suddenly extended to 15 cent., the deviation 
ought to have been notably increased, in the same direction, if electric 
currents existed in the nerves. There was nothing; or rather the needle 
did not deviate to a greater number of degrees than in the preceding case, 
and its deviation was still only momentary, or else was entirely wanting. 
It is important to bear in mind that during the continuance of these 
experiments, in consequence of the pain which was voluntarily excited in 
the animal, its posterior train was the seat of energetic and repeated efforts, 
and that, consequently, the extremities of the galvanometer were put into 
