268 APPENDIX, [No. XVII. 



fectly analogical. Both possess a power only limited by the strength of 

 the materials. In both cases, the power acts over the short end of the 

 lever, and therefore at a mechanical disadvantage. In both cases it is a 

 great power moving over a small space. I, however, can move my natural 

 muscles much quicker than I can my artificial muscle ; but you must 

 please to remember that my organs are not competent to construct a 

 machine having such fine tubes as we find in the ultimate muscular 

 fibrils ; and for want of this delicacy of construction we sacrifice the 

 speed and rapidity of action observable in the perfection of Nature's 

 operations. 



Anxious to lay before you the leading experiments and deductions of 

 this truly delightful subject, I have delivered this lecture with the utmost 

 possible rapidity, and yet I see around me multitudes of experiments which 

 I fear that I shall have no time to explain, as the hour has already passed. 

 By your applause, I understand that you wish me to proceed ; but as some 

 of my audience live at considerable distances, I will only detain you by 

 calling your attention very briefly to a few other points. In the first 

 place, we find that man consists of a double voltaic circuit, and therefore 

 we ought to consider the nature of the changes taking place in that voltaic 

 circuit. Now, there are strong reasons to suppose that hydrogen and 

 carbon act as the positive pole, and become changed in that capacity into 

 water and carbonic acid. It would only require one thirty- second the 

 quantity of these materials to produce any result that it would of zinc ; 

 and I can assure you, that many a time have I sought diligently and care- 

 fully for a voltaic circuit which should be efficiently excited by carbon or 

 coke as a positive element ; and I can promise to the fortunate discoverer 

 of such a combination the delight of being able to supersede the steam- 

 engine, and the pleasure of successfully generating the voltaic light. 

 Then, and not till then, will voltaic batteries be employed to the exclusion 

 of every other means of generating force. Although up to the present 

 time I have not been able to use coke or carbon for a positive pole, I have 

 succeeded in making a variety of circuits, in which substances composed 

 of carbon and hydrogen form powerful voltaic circuits ; for instance, 

 sugar and nitric acid, oxalic acid and chloride of gold, ferrocyanate of 

 potash and nitric acid, constitute examples of this class of batteries. 



The voltaic circuit in animals is exactly balanced, and does not act 

 without some impression to set in motion the electric current. The 

 arterial or oxygenized corpuscles are admirably adapted for this purpose, 

 and I have here an experiment which will illustrate their functions in a 

 very beautiful manner. The glass vessel which I hold in my hand contains 

 a solution of common salt, and two iron poles are inserted into it. Now 

 in this state everything is balanced, and no voltaic force is exhibited. If I 

 take an artificial corpuscle made of animal membrane, containing a little 

 pernitrate of iron, and bring it in contact with one of the iron poles, 

 a very powerful deflection of the galvanometer ensues, indicating the 

 presence of a current. When, however, one corpuscle is placed against 

 each plate of iron, the effect is again balanced, and no voltaic circuit arises. 

 These experiments well indicate the functions of the blood-corpuscle in the 

 living body ; for when one is in contact with each end of the nerve-fibre, 

 no current can take place, but the moment one is removed, or acted upon 

 by heat, light, or other forces, a strong voltaic battery is formed. 



