1869.] Dr. C. B. RadclifiVs Researches in Animal Electricity. 377 



III. "Researches in Animal Electricity." By Charles Bland 

 Radclifee, M.D. Communicated by C. Brooke, F.R.S. 

 Received, Part L, Feb. 18 ; Part II.-V., March 11, 1869. 



(Abstract.) 



After a description of certain instruments, now employed for the first 

 time in researches of this kind, the topics inquired into successively are : — 

 the electrical phenomena which belong to nerve and muscle in a state of 

 rest ; the electrical phenomena which mark the passing of nerve and 

 muscle from the state of rest into that of action ; the motor phenomena 

 ascribed to the action of the " inverse " and " direct " voltaic currents ; 

 and electrotonus. 



I. On certain Instruments now employed for the first time in Researches 

 in Animal Electricity. 



The instruments here referred to and described are Sir Wm. Thomson's 

 Reflecting Galvanometer, Mr. Latimer Clarke's Potentiometer, and some 

 new electrodes devised by the author. 



Sir Wm. Thomson's Reflecting Galvanometer, which is the principal 

 galvanometer made use of, is stated to be more manageable than the old 

 galvanometer of Prof. Du Bois Reymond, and not less sensitive. 



Mr. Latimer Clarke's " Potentiometer," which is really a very ingenious 

 adaptation of the idea upon which the Wheatstone's Bridge is based, is the 

 instrument employed for the measurement of tension. It is so delicate as 

 to measure with certainty the part of the tension of a Daniell's cell. 



The new electrodes are simply pieces of platinum wire, flattened and 

 pointed at the free ends, and having these free ends freshly tipped with 

 sculptor's clay at the time of an experiment. The necessary homo- 

 geneity of the two is secured by pushing the clay a little further on 

 one of the wires, or by pulling it a little further off ; for by a simple 

 manipulation of this kind it is found that the clay tips of the two elec- 

 trodes may be so adjusted as to allow them to be brought together 

 without the development of the slightest current. After a very little 

 practice it is found, indeed, that in a very few moments the two electrodes 

 may be made perfectly homogeneous by thus covering or uucovering one 

 of them. And, further, it is found that the secondary polarization arising 

 from the passage of a current may be got rid of at once by simply bringing 

 the clay tips of the two electrodes together so as exclude the polarizing 

 current from the circuit of the galvanometer, and by leaving them in this 

 position for a moment or two — by short-circuiting the galvanometer, that 

 is to say, for a very brief period. It is found, in short, that these electrodes 

 are infinitely more manageable, and not less effectual, than the electrodes 

 commonly in use, in which enter zinc troughs filled with saturated solution 

 of zinc, and pads of blotting-paper, the pads being kept sodden with this 



