PEOFESSOE MATTEUCCI’S ELECTEO-PHTSIOLOGICAL EESEAECHES. 
131 
Perhaps it may not be devoid of interest to note the result of a comparative experi- 
ment made on the same number of frogs similarly prepared, and suspended in the same 
way in two separate bottles, with this difference only, that the frogs in one of the bottles 
had been firmly bound together with a ribbon wound many times round them : the 
passage of the interrupted current through the lumbar nerves could not awaken in the 
latter any general movement of the limbs, but produced a palpitation in the muscles 
which appeared to diminish rapidly. The frogs thus confined showed an increase of tem- 
perature during the passage of the current, but to a much less degree, being in each of the 
two experiments about one-third less than that of the frogs which were suspended freely. 
§ 2. I now proceed to treat of the development of electricity in muscles during 
contraction. 
Before entering more fully on this subject, I think it advisable to describe some new 
researches on muscular electricity. Two methods have been hitherto followed in order 
to arrive at a rigorous demonstration of the principal facts and laws of muscular electri- 
city. In one of these methods the muscular elements are united in form of a pile, and 
the intensity of the muscular current increases with the number of muscular elements 
of the pile : this fact suffices to exclude any doubt of the existence of electromotive power 
which might be generated by the platinum plates of the galvanometer, or by the liquid, 
in which the pieces of muscle forming the outer elements of the pile are plunged. This 
doubt is also excluded by employing the nerve of the galvanoscopic frog instead of a 
galvanometer. 
The other method, which is that employed by Nobili and myself in my earlier 
researches on the electrical current of the frog, has been greatly improved by M. Du Bois 
Keymond, who has rendered it sure and of easy application. The apparatus of M. Du Bois 
Reymoxd consists, as is well known, of two small glasses, in each of which is laid a thick 
strip or cushion formed by numerous layers of blotting-paper or flannel ; one extremity 
of this cushion touches the bottom of the glass, while the other rests on its edge so as 
to form a short horizontal stratum. By means of two little wooden columns, the pla- 
tinum plates of the galvanometer are held vertically in the liquid, which is a solution of 
common salt, and remain in constant contact with the paper or flannel cushions above 
described. At first the two cushions are held in contact until all heterogeneity between 
the platinum plates has ceased ; the two glasses are then drawn asunder, so as to leave a 
small interval between them. A gastrocnemius or a half-thigh of a frog laid on a 
narrow strip of gutta-percha held in the hand, is placed in contact with the conducting 
cushions so that the circuit is closed with the extremity of the muscle. The initial or 
impulsive deflection of the needle, which is of 40° or 50°, when the galvanometer is very 
delicate, ceases almost immediately if one element only is employed instead of a pile : 
if the muscle is removed and the conducting cushions are brought into contact, there is 
a great deflection in the opposite direction, owing, as is already kno’wn, to polarization. 
I had learnt from many experiments made long since on the electrolytic action of 
induced currents, that the best way of avoiding polarization is the substitution of care- 
T 2 
