ELECTEIZATION BY REFLEX ACTION. 121 



direction of the nerve-branclies whicli proceed to muscles, and 

 never in tlie contrary direction. It follows that electrization of 

 the nerve-terminations of limbs will never call into contraction 

 muscles which receive their nerve-filaments from branches given 

 off above the point excited. 



This is, in fact, what occurs when we localize electric excitation 

 in the terminations of nerves, by holding both the rheophores of 

 a galvanic battery, or an induction apparatus, in one hand (with 

 the well understood precaution that the circuit shall not be com- 

 pleted by allowing them to come into contact). We then experience 

 some contraction of the muscles of the thenar and hypothenar 

 eminences, produced by direct excitation of the muscles, with 

 pricking and tingling in the fingers, under the influence of the 

 equally direct excitation of the collateral nerves, or of the digital 

 tissues ; the muscles of the forearm do not enter into contraction. 



But if, in place of holding both rheophores at the same level in 

 a single hand, one is separated from the other, either by placing 

 one in the hand and the other higher up on the limb, or by holding 

 one in each hand, we then see contraction of the muscles of the 

 fore-arm or arm, according to the degree of intensity of the 

 current. The. muscular contractions produced by this method of 

 electrization are irregular, and do not correspond with the degree 

 of pain that accompanies them. The pain, indeed, is not confined 

 to the muscles in contraction, but extends to the wrists or the 

 elbows, or even to the shoulders when the current is intense. The 

 sensation in that case is very painful, and leaves behind it an 

 aching of the joints. 



In these various experiments the excitation is always greatest 

 in the arm the hand of which grasps the positive pole, so that it 

 receives an ascending current. From these two experiments I 

 draw the following conclusions : — 1. Electrization localized in the 

 nerve-terminations of a limb produces only local phenomena in 

 accordance with the functions of the organs excited ; that is, 

 sensations limited to the part. 2. In order to produce con- 

 tractions of muscles situated above the nerve-terminations, it 

 is necessary to separate the rheophores in such a manner that 

 the currents may traverse the limbs, or rather their nerves, in 

 a longitudinal direction ; this is electrization hi/ reflex action. 

 3. Lastly, the electrization by reflex action operates specially 

 upon the sensibility, ascends to the posterior roots of the nerves, 

 affects the anterior roots, and thus produces, in the muscles 

 dependent uj)on the nerves the terminations of which have been 

 excited, irregular contractions that are but little in harmony with 

 the intensity of the sensations. 



