Matteucci’s Lectures on Living Beings. 395 
the production of the phenomena; that is to say, the contractions 
by induction do not occur in the galvanoscopiec frog; but on the 
contrary, a leaf of fine paper moistened with water, does not pre- 
vent the occurrence of this contraction.’ 
Various experiments were performed with great care by Mat- 
teucci, to ascertain the true nature of the cause of these contrac- 
tions, and he concludes that they are due to a nervous force an 
not to electricity. In the course of his argument on this subject, 
e says:—‘ We might believe’ in the development of electricity 
independently of the proper and muscular currents. But how can 
We stippose such a fact, when we see that the induced contrac- 
tion is transmitted through certain insulating substances such as 
turpentine, oil, &c., while it no longer does so if we employ very 
thin leaves of mica. We might suspect that electricity, develop- 
during muscular contraction, acted by influence. In this hy- 
pothesis, we can understand why turpentine offered no obstacle 
to the passage of the contraction by induction ; but the other fact, 
that with an extremely thin plate of mica, the same result does 
not happen, makes it doubly inexplicable. I have tried the effect 
of covering a galvanoscopic frog, placed on a glass plate, with a 
plate of mica; the discharge from a Leyden bottle, passed be- 
tween the knobs of the excitor upon the mica plate, and contrac- 
tions were excited in the galvanoscopic frog. I shall not now 
Stop to analyze this fact; it is sufficient for the present to show, 
that induced contraction through the mica ought to have occur- 
ted, if the cause of the phenomenon resided in an electric dis- 
charge, or was the result of the latter. I shall conelude by add- 
ing that I have endeavored repeatedly, but always unsuccessfully, 
to excite contraction in the frog by holding the nerve of the gal- 
Vanoscopic frog in proximity with, or even in contact with a me- 
tallic conductor traversed by an electric current. In order to find 
out the most favorable conditions, and in order that the circuit by 
hished. When all these precautions are taken, in order that the 
og may be 
Cited in the latter, at the commencement, at the opening, or at 
the ¢losure of the circuit of the pile. It must be remarked, that 
In thi®experiment the circuit by induction may take place com- 
pletely in the frog. I employed Bunsen’s pile of ten elements 
without obtaining any other result.’ 
_ Scop Szrixs, Vol. V, No. 15.—May, 1848. | 
