242 Electricity and Galvanism. 



utmost extent with free negative electricity. I think this evaporation 

 may probably account for the traces of free electricity generally to be 

 detected in the body by merely insulating a person and placing him 

 in contact with a condensing electrometer. Pfaif and Ahrens generally 

 found the electricity of the body thus examined to be positive, espe- 

 cially when the circulation had been excited by partaking of alcoholic 

 stimulants. Hemmer, another observer, found that in 2422 experi- 

 ments on himself, his body was positively electric in 1252, negative 

 in 771, and neutral in 399. The causes of the variations in the cha- 

 racter of the electric condition of the body admit of ready explana- 

 tions in the varying composition of the perspired fluid. For if, con- 

 taining, as it generally does, some free acid, it by its evaporation 

 would leave the body positively electric ; whilst it merely contains 

 neutral salt, it would induce an opposite condition. The accuracy of 

 these statements can be easily verified by means of the galvanometer. 



It is impossible to quit this part of my subject without calling to 

 mind the fact, that, independently of combustion, chemical action, or 

 evaporation, the mere contact of heterogeneous organic matters is 

 competent to disturb electric equilibrium. Thus a pile of alternate 

 slices of muscular tissue and brain, with pieces of wet leather inter- 

 posed, has been found by Lagrave to evolve electricity ; and Dr. 

 Baconio, of Milan, has shown that a few alternations of slices of beet- 

 root and wood of the walnut-tree were capable of setting free suffi- 

 cient electricity to excite convulsions in a frog when conveyed to its 

 muscles by means of a conductor formed of a leaf of scurvy grass. 

 Matteucci has thrown out the suggestion, that the organization of a 

 muscle is possibly such as thus by heterogeneity of structure to 

 account for the development of electricity ; he considers the analogy 

 between the voltaic arrangements and the constitution of muscle to 

 be complete, if we conceive the zinc, or oxydising plate, to be repre- 

 sented by the true fibre, the platinum, or conducting plate, by the 

 sarcolemma, and the exciting fluid by the blood. 



In summing up the foregoing facts, we are, I think, justified in 

 concluding that a mass of evidence has been adduced demonstrative 

 of the actual existence of electricity in three states in the body : — 



1 st. In a state of equilibrium, common to all forms of ponderable 

 matter. 



