38 



REPORT — 1844. 



Some impressions, sent by Dr. Hamel, from Daguerreotype plates, which had been 

 etched in Paris by the agency of an acid, were exhibited. 



Mr. Matteucci communicated to the Section the i-esults of some experiments made 

 by him v;ith the view of estabUshing the relation which the amount of mechanical work 

 realized by the consumption of a given quantity of zinc acting as a voltaic combina- 

 tion upon the limbs of a fiog, bears to the amount of work realized by the same quantity 

 of zinc employed as a generator of mechanical force in other inoi-ganic applications. 

 A given weight is attached to the feet of a recently-prepared frog, this and the weight 

 are suspended from a platina wire by the portion of the spine, and another platina 

 wire passes through the lower part of the sciatic nerves ; these wires are connected 

 with the terminals uf a voltaic battery, a voltameter being interposed in the circuit. 



By making and breaking voltaic contact, the muscles contract, the weight is raised. 



By connecting a contact breaker with the moving limbs, these are enabled to inter- 

 rupt and complete the voltaic circuit by their own contractions, and a register attached 

 shows the number of interruptions in a given time. 



An index is also attached to the weight, which bearing upon a revolving sooted disc 

 ret'isters the distance and velocity of the motion of the weight. Thus we get the elements 

 of time, space, and weight. From experiments performed in this manner M. Mat- 

 teucci finds that 3 milligrams of zinc consumed in twenty-four hours give S^o'lig of 

 weight raised through a given space, while the same quantity of zinc, or its equivalent 

 of carbon, employed to generate motion by combination in a steam-engine gives 0^-834 ; 

 or employed to work an electro- magnetic machine, gives 0^-9(3. 



Several reductions must be made to eliminate extraneous actions which do not con- 

 tribute to the resulting effect ; thus a voltaic battery of sufficient intensity to decom- 

 pose water must be much more powerful than is requisite to convulse the limbs of the 

 fro". The conductinf power of the pelvic muscles, which if cut oft" weaken too much the 

 general effect, must also be deducted, as well as the antagonist force of the extensor 

 muscles. The necessity for all these reductions makes the problem a very complex one. 

 M. Matteucci believes, however, that he has done sufficient to establish the general re- 

 sult that a far greater amount of work can be realized from the consumption of a given 

 quantity of zinc acting on the limbs of a recently-killed animal, than when the same 

 quantity is employed to work an inorganic machine ♦. 



* On the 30th September, M. Matteucci showed at his lodgings to several Members 

 of the Association, some of the most important of the experiments detailed in his re- 

 cently published work on Electro-Physiology. 



1st. The Muscular Current. — If the sciatic nerve of the limb of a prepared frog be 

 made to touch at the same time the external and internal muscle of a living or re- 

 cently-killed animal, the limb is convulsed. By forming a series of external and in- 

 ternal muscles, for instance, severing the lower halves of the thighs of a certain number 

 of frogs, and inserting the knee of the one into the central muscle of the second, and 

 so on, a voltaic pile will be formed, six or eight elements of which M. Matteucci 

 showed were capable of deflecting a galvanometer, or producing convulsions in an 

 electroscopic frog. 



The direction of the voltaic current is from the interior to the exterior of the muscle, 

 and the current is more feeble in proportion as the animal is higher in the scale of 

 creation. 



2nd. M. Matteucci explained the specific voltaic current (courant propre) of the 

 frog as being a current which is detected only in the frog, and which is directed from 

 the feet to the head of the animal. 



3rd. M. Matteucci showed an experiment by which it appeared that a muscle whilst 

 undergoing contraction is capable of exciting the nerve of another recently-killed 

 animal, so as to produce muscular contraction in the latter. He laid the sciatic nerve 

 of one kg of a prepared frog on the thigh of another, and by touching the nerve of 

 the latter with an arc of zinc and copper this was convulsed, and at the same time 

 the first le"-, the nerve of which formed no part of the voltaic circuit, was simultane- 

 ously convulsed, the legs all moving as though they formed part of the same animal. 



4th. M. Matteucci explained some joint rcsearehes of himself and M. Longet, by 



