T 
134 PEOrESSOE MATTEECCI’S ELECTEO-PHTSIOLOGICAL EESEAECHES. 
I take this opportunity of calling attention to a fundamental difference existing between 
a muscular electromotor and a voltaic pile. Let us take an entire muscle, such as the 
thigh of a frog, and cut it in half: it is known that the two sections thus fonned have 
the same electrical state, and that a pile can be formed by placing in contact the internal 
section of one of the half-thighs with the superficies of the other. This result cannot be 
obtained with a voltaic pile : on the other hand, the proposition which we are now con- 
sidering, leads us to admit a certain analogy between a muscular electromotor, and the 
organ of electric fish or the voltaic pile. 
The relation existing between muscular electricity and the physiological conditions 
of muscle, forms the subject of the next proposition. 
Prop. III. The electromotive force of muscles, in living or recently hilled animals, is 
greater in mammifers and in birds than in fish and in amphibia : the duration of this force, 
which in all cases decreases most rapidly in the first moments after death, is greater in fish 
and amphibia than in the muscles of the higher orders of animals. The nerves have no direct 
influence on the electromotive force of muscles. In general, all the causes ivhich exeit an 
influence on the physical structure and chemical composition of muscle, to modify in ivays 
unknown its irritability or contractility, act equally on its electromotive power. 
This proposition is founded on experiments which I have already published, and par- 
ticularly on those described in the Memoirs contained in the Philosophical Transactions. 
Since their publication I have frequently repeated and varied these experiments, employ- 
ing the new method above described, and have succeeded in fully confirming them. I 
shall here only add a very brief description of some of these experiments, which place the 
existence and nature of muscular electricity in the clearest light. The object of the first 
of these experiments is to compare the electromotive power of the muscles of pigeons, 
rabbits and frogs. 
For this purpose, I form, with muscles of these animals rapidly prepared, the usual 
elements which I oppose to each other. I form thus several double pdes of muscular 
elements of frog and pigeon, of frog and rabbit, of pigeon and rabbit, and I measure 
successively the differential currents of these piles, closing the cii’cuit of the galvanometer 
with the usual platinum plates. At first, the electromotive power of the muscles of the 
pigeon and of the rabbit greatly predominate over that of the muscles of the frog. After 
twenty or thirty minutes the differential current is null, or already inverted, and after the 
lapse of an hour or more, this inverted current, due to the muscles of the frog, is remarkably 
increased : this takes place in the pile of pigeon and frog sooner than in that of rabbit 
and frog. 
Another very conclusive experiment is made on muscles exposed to great cold. Several 
gastrocnemi and half-thighs of frogs are left in a glass tube, siu'romided by a mixture of 
salt and ice: after twenty or thirty minutes it is found that these muscles have entirely lost 
their electromotive power. By forming the usual piles with frozen and imfrozen muscles 
opposed, we acquire the certainty that the frozen muscles have lost their electromotive 
power, but not their conductivity. If we operate on muscles of frogs which have perished 
in nitrous or hydro sulphuric acid, we obtain the same results as from fi'ozen muscles. 
