130 ANNUAL OP SCIENTIFIC DISCOVERY. 



that can be deduced from the foregoing investigations, contained in the 

 former as well as present papers, arc the following: 



1st. That we have no evidence of being able to increase the polarized 

 condition of the nervous and of the muscular tissue by artificial means, such 

 as the electric current ; but it is highly probable. 



2d. That an increase of this polarized condition may arise from an in- 

 creased action of those changes which take place in the living animal, such 

 as nutrition, being the same means by which it is produced and maintained 

 in the living animal. 



Before acceding to these conclusions, it may be reasonably asked, have 

 we not other evidence besides that afforded by means of the galvanometer, 

 to indicate an increase in the polarized condition of the nerve? Do not the 

 tetanic contractions which are observed in a limb whose nerve has been sub- 

 jected to the action of an electric current (inverse), indicate an increased 

 action of the nerve? Previous to discussing this question, which will be 

 considered in the concluding remarks, the following experiment was per- 

 formed: 



A current from six of Grove's cells was passed through the limb of a gal- 

 vanoscopic frog in the inverse direction, and as soon as the tetanic contrac- 

 tions were produced, the nerve was divided at the junction of the nerve with 

 the muscles of the limb; the tetanic contractions ceased. The two ends of 

 the divided nerve were now placed in apposition, but no tetanic contractions 

 ensued. This inverse current was again allowed to pass for some time 

 through the nerve thus united, but no tetanic contractions occurred upon 

 the breaking of the circuit. Great care, however, is required in this experi- 

 ment to divide the nerve at the exact point where it emerges from the mus- 

 cles, as pointed out by Matteucci, otherwise the tetanic contractions take 

 place. 



The results of this experiment only tend to confirm what has been already 

 satisfactorily proved by others, that the continuity of the nerve fibre, in the 

 nerve leading to the muscle, is necessary for the conduction of the impres- 

 sion excited at the distal end of the nerve in order to arouse muscular con- 

 traction. It need scarcely be added, that the muscular and nerve currents 

 may, however, be obtained under these circumstances between the separated 

 portions. 



* 



POCKET ELECTRO-MEDICAL APPARATUS. 



M. Despretz has recently submitted to the Paris Academy a new Electro- 

 Medical apparatus, invented or combined by Ruhmkorff, and reduced to its 

 simplest condition. A small box, in size about four cubic inches, contains : 

 1. An induction coil; 2. A small Bunsen's pile of zinc and charcoal, in 

 which nitric acid is replaced by Marie-Davy's sulphate of mercury; 3. Some 

 handles, a brush, and some needles for distribution of the direct currents, 

 or of the extra current to the surface of the patient. The manipulation of 

 the apparatus is as simple as its construction. Xo vapors are disengaged. 

 This apparatus will maintain its activity during a day. Its price is said to 

 be moderate. 



APPLICATION OF THERMO-ELECTRICITY TO SURGERY. 



Thermo-electric currents are now extensively employed by Middledorp, of 

 Breslau, in surgery. With wires and blades of platina of various dinien- 



