CHAP. Vni. MUSCULAR AND NERVOUS TISSUES. 87 



not become free, but be exerted in some other 

 manner, as heat s. 



Before concluding, although I have alluded to the 

 subject in chap, i., it may be remarked, that we are 

 now brought to the consideration of the explanation 

 of Galvani's celebrated experiment, viz. the eon- 

 traction that ensues when the nerve is brought into 

 contact with the external surface of the muscle. 

 Galvani compared the muscles to a charged Leyden 

 jar, the two surfaces, the external and internal, being 

 in opposite electric states; and he considered that 

 when the circuit was completed, the contraction was 

 a necessary consequence of the passage of electricity 

 from one surface to the other by means of the nerve. 

 No one can deny that Galvani was so far correct; 

 he erred in considering the electricity as secreted in 

 the brain, and transmitted by the nerves to different 

 parts of the body, the muscles serving as mere 

 reservoirs of the electricity ; overlooking the fact, 

 pardonable at his time, that electricity might be 

 developed in other parts as well as in the brain. 

 VoLTA erred in denying the origin of the power in 

 the animal body, but was correct in pointing out 

 that similar effects could be obtained by other means 



8 Dr. Badclifie has published some vieTrs in regard to muscular 

 contraction, in which he considers the muscle as being the seat 

 of "polar action" and contraction as the result of molecular 

 attraction. I cannot do better than refer to the Paper for the 

 arguments upon which his conclusions are founded, which will 

 be found published in the Medical Times and Gazette, June, 

 1835. 



