PROFESSOR MATTEUCCI’S ELECTRO-PHYSIOLOGICAL RESEARCHES. 
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from an ordinary pile of from 30 to 40 elements, applying one of the poles to the 
upper, and the other to the lower part of the thigh. If the positive pole is placed 
above and the negative below, the current traverses the muscle in the same direction 
as the ramification of the nerves ; the contrary is the case if the position of the poles 
be reversed. 
Experiments of this kind date from the earliest times of galvanism ; but the dif- 
ficulty in these researches of separating truth from error, that which is constant and 
invariable from that which is merely accidental, and, above all, the still imperfect 
state of electro-physiological science, have hitherto prevented the attainment of any 
positive conelusions. 
In experiments on this subject, great precaution is necessary in order to be certain 
that the electric current does not traverse the nervous filaments of the muscle ; this 
certainty is obtained, as we have already seen, by keeping the poles of the electrical 
pile in contact with the surface of the muscle, at the greatest possible distance from 
the nervous filaments which spread through its interior. We must carefully remove 
from the surface of the musele all traces of blood or other liquids ; and I have gene- 
rally been in the habit of applying one pole to the upper and the other to the under 
surface of the muscle. ^ 
When the electric current traverses the muscular mass of the thigh of a living 
animal in the same direction as the ramification of the nerves, a very strong con- 
traction always takes place, which contraction is excited not only in the muscle di- 
rectly traversed by the current, but also in the inferior muscles of the leg and in the 
foot. 
When the electric current traverses the muscular mass in the contrary direction 
to that of the ramification of the nerves, the animal utters loud cries, and gives other 
indications of suffering severe pain, accompanied by contractions much less violent 
than in the preceding case, and which never extend beyond the muscles traversed by 
the current. 
If we were to satisfy ourselves with seeing these experiments once only, or were to 
confine ourselves to a few trials only, we might easily be led to form an erroneous 
conclusion ; in fact, at the beginning of the experiment, particularly if a somewhat 
powerful current be employed, there are both cries of pain and contractions at the 
same time ; but this soon ceases, particularly if we know how to regulate duly 
the strength of the current. The constant effects which distinguish the action of the 
electric current, according to its direction, in the muscles of living animals, are those 
which I have indicated, namely, pain, when the electric current is what is commonly 
called inverse, — contraction, when the current is direct. 
Now, setting aside all hypothesis, there can be but one way of explaining these phe- 
nomena : when there is a contraction, there must necessarily be a current of nervous 
force propagated from the brain towards the extremities of the nerves : when there 
is a sensation of pain, this current must be impelled in a contrary direction, that is. 
