316 Supposed Agency of Galvanism iri transferring Colors, 4'C. 



Art. X. — -Supposed Agency of Galvanism in transferring Colors 

 through animal substances ; in a letter from Dr. Alei^ander 

 Jones, of Athens, (Geo.) to Geo. W. Carpenter, of Philadelphia. 



(Communicated for this Journal by G. W. C.) 



Having seen it stated in a late number of the American Journal 

 of Medical Sciences, that, if a fluid colored blue, was inclosed with- 

 in a bladder, and then immersed in another fluid colored red, that on 

 standing for some hours, it was found that a portion of its coloring 

 matter had found its way through the coats of the bladder, and had 

 mixed with the red fluid, while a portion of the red fluid had passed 

 from without into the bladder and mixed with the blue fluid, thus 

 demonstrating that two currrents had been formed through the blad- 

 der. Reflecting on the cause of this double transposition of the col- 

 oring fluid, I was led to believe, if the experiment was true, that 

 it depended probably on galvanic agency : that one colored fluid was 

 positive, while the other was negative ; and that a change of position 

 took place, the process of which might be called electrical percola- 

 tion. The experiment appeared so interesting to me, that I deter- 

 mined to repeat it in various ways. For this purpose I formed a vol- 

 taic pile of about forty pairs : between the wires of the negative and 

 positive pole I placed three wine glasses. Two of the glasses in 

 which the positive and negative ends of the wires were made to ter- 

 minate, were nearly filled with clear water. The middle glass was 

 filled with an infusion of cochineal. I also inclosed a small quantity 

 of an infusion of litmus in a piece of beef's bladder, which was se- 

 curely tied and immersed in the middle glass, containing the infusion 

 of cochineal. I connected the glasses by means of small pieces of 

 brass wires. In a short time I found that a portion of the enclosed 

 infusion of litmus had found its way through die coats of the bladder, 

 and commingled with the infusion of cochineal on the sides of the 

 bladder next the negative pole. I removed the pieces of wires, and 

 connected the glasses with moistened strips of beef's bladder. In 

 two or three hours I found a portion of the litmus coloring matter 

 had passed through the connecting slip of bladder, and collected in 

 the negative wine glass of clear water, so far as to communicate to it 

 a sky blue tinge. The clear glass of water at the positive pole, re- 

 mained unchanged in color : on adding a small quantity of sulphuric 

 acid to the negative glass, it was changed to a pale red, proving the 

 presence of the litmus color. On opening the piece of bladder en- 

 closing the infusion of litmus, I found it had assumed a reddish or 



