CHAP. X. §. I. DUEING MUSOULAE CONTBAOTION. 119 



secretions upon the fluids. Although we cannot 

 remove these sources of error, we have it nevertheless 

 in our power to counteract their effects, by shewing 

 that the current consequent upon muscular con- 

 traction can be made to overcome that arising from 

 either of the two former actions. 



I have not yet alluded to the difference which 

 appears to exist between the results obtained by 

 Du Bois Eeymond and myself, viz. the direction of 

 the current. Dn Bois Eeymond's experiments indi- 

 cate that the current is inverse, i. e. from the hand to 

 the shoulder during muscular contraction; my re- 

 sults, on the other hand, point out that the current 

 is direct, i.e. from, the shoulder to the hand. I do 

 not think that my results differ much from those of 

 Du Bois Eetmond; bit as the discussion of this 

 question wiU involve certain theoretical views, what- 

 ever observations I may have to make will be deferred 

 to the concluding remarks °. 



» My original Paper was read before the Eoyal Society, since 

 then I have had the opportunity of attending the interesting 

 lectures of Du Bois Eeyhond at the Boyal Institution. Du Bois 

 Beiiiiconi) considers, as far as I could understand, that when the 

 whole of the hands are immersed in the solution, and the 

 muscles of the arm are made to contract, then the current is 

 4ue to the swollen state of the sMn, and perhaps to other cir- 

 cumstances ; but should we be justified, I would ask, in con- 

 cluding, that when the fingers alone are in the vessel, that then 

 the effect is due to their swollen state 1 If Du Bois Eetmond 

 maintauis that the current due to muscular contraction is 

 inverse, i. e. from the hand to the shoulder, I can only add that 

 I have never been able to obtain that constant effect. It cannot 



