190 Mr. H. F. Baxter on the Force evolved 



The results obtained by Despretz*, Becquerelf and Mat- 

 teucci X, have thrown strong doubts upon the conclusions deduced 

 by Du Bois-Keymond. Several experiments undertaken by the 

 author of the present paper, both prior and subsequent to the 

 knowledge of Du Bois-Reymond's researches, tended to confirm 

 in his opinion the doubts expressed by these inquirers. But the 

 positive evidence adduced by Du Bois-Reymond by means of 

 his galvanometer, combined with that of Matteucci obtained by 

 means of the frog, only made it incumbent upon the opponents 

 of Du Bois-Reymond to disprove his conclusions, if capable of 

 disproof, more by stronger experimental evidence than by theo- 

 retical arguments ; hence the renewal of the present inquiry. 



In relating the experiments, to avoid unnecessary prolixity, 

 we shall endeavour to be as concise as possible, incurring, how- 

 ever, some risk of being considered as not having sufficiently 

 eliminated the sources of error. Our great point will be to 

 establish facts ; and whatever observations we might think ne- 

 cessary to make in reference to the origin of the effect produced, 

 these will form the subject of the concluding remarks, and may 

 be considered as distinct from the main object of the paper. 

 We shall relate in a general manner some results that were 

 obtained by means of a galvanometer consisting of but few coils. 

 To two brass handles of an ordinary medical electro-magnetic 

 machine, were attached thick copper wires, each about 8 inches 

 in length, and bent. Similar copper wires were connected with 

 the galvanometer, their free ends communicating with mercurial 

 cups, these cups forming the means of connexion with the brass 

 handles. Holding the metallic handles firmly, grasping one of 

 them and contracting the muscles of the arm powerfully, and 

 doing this alternately with each arm, we at first failed to obtain 

 any, or if any, but indecisive results. Upon repeating the expe- 

 riments on another occasion, we ultimately obtained some defi- 

 nite result and a clue to our former failures. It was found that 

 when the muscles of the arms were contracted alternately at 

 definite periods, and continuing this act for some time, that as 

 the hands became moist a decided effect upon the needle occurred, 

 indicating the conti'acting arm to he positive^ to the other. We 

 considered that these results were due partly to the reaction of 

 the acid secretions of the hand upon the metallic electrodes, 

 partly to the skin becoming a better conductor than the dry 

 cuticle, and partly perhaps to thermo-electric action. 



* Comptes Rendtts, vol. xxviii. p. 653. 



t Ibid. p. 663. X Ibid. p. 782. 



§ If we take an elementary circle, such as zinc, platinum, and dilute acid, 

 the current goes from the zinc, through the fluid, to the platinum, the pla- 

 tinum being the positive electrode. 



