12 Mr. H. F. Baxter on Nei-ve Force. 



First. The nervous tissue, like the muscular tissue, possesses 

 an electric state. 



Secondly. This electric state is developed during, and main- 

 tained by, nutrition. 



Thirdly. The electric force of the nervous tissue is not con- 

 verted into current force during nerve action. 



Fourthly. Whether the electric force of the tissue is converted 

 into ner re force during nerve action was left an open question. 

 It is this question I propose considering on the present occasion. 



§ I. On the conversion of the electric force of the nervous 

 tissue into nerve force during nerve action. 



Assuming my readers to be acquainted with the conditions 

 under which the so-called nerve current is obtained in the living 

 or recently-killed animal, viz. by placing the electrodes of a 

 galvanometer, one in contact with the transverse section, the 

 other in contact with the longitudinal surface of a nerve, the 

 point for consideration is this : — Can we obtain any evidence of 

 a sudden decrease in the nerve current during nerve action 

 indicative of a loss in the electric state of the nerve, and which 

 loss may give rise to the development of nerve force, — in other 

 words, a conversion of the electric force into nerve force in accord- 

 ance with the principle of Conservation of Force * ? 



To avoid unnecessary repetition I will sum up the general 

 results of my experiments, as my object will be, not to study the 

 development of the nerve current, but merely the effect upon it 

 during the excitement of the nerve. 



The animal (guinea-pigs, rabbits, and frogs) having been 

 pithed, to avoid too great motion of the limb, the leg was fastened 

 down ; the sciatic nerve was then exposed throughout its whole 

 course, and a piece of thin glass placed beneath it. One of the 

 electrodes of the galvanometer being pointed and coated with 

 shell-lac, excepting the extreme end, was inserted into the 

 nerve ; the flat end of the other electrode was placed on the 

 surface of the nerve, sometimes on the distal side, at other times 

 on the spinal side of the other. The distance between the 

 electrodes varied. As soon as the circuit was completed and 

 the nerve current obtained and noted, the spinal extremity of the 

 nerve was excited by a small galvanic circle, or by a single cell 

 of Grove's battery, so as to produce violent contractions in the 

 muscles of the lower limb. The effect upon the galvanometer 

 needle was that of a slight oscillation ; there was no sudden or 



* Faraday " On the Conservation of Force," Philosophical Magazine, 

 April 1857. Professor Helmholtz " On the Application of the Law of Con- 

 servation of Force to Organic Nature," Medical Times and Gazette, 

 April 20, 1861. 



