80 LOCALIZED ELECTRIZATION. 



phenomena, ignorance of which might lead to many errors, and 

 sometimes even to serious accidents. 



A. — Excitahility of (he motricity of nerves, and the contractility 



of muscles. 



The motricity ^ of the external branch of the spinal nerve {re- 

 spiratory nerve of Bell) is the most excitable. Hence the muscles 

 or parts of muscles that it supplies will be thrown into action 

 by a very feeble electric current. For example, the lower half of 

 the sterno-cleido-mastoid, and the middle and inferior portions 

 of the trapezius, are but little excitable. But, if we direct upon 

 the superior half of the sterno-mastoid, or upon the external border 

 of the upper half (the clavicular portion) of the trapezius, a current 

 that is too weak to produce even the commencement of contraction 

 in the other parts of the same muscles, we see the head bent, or 

 the shoulder elevated, or the side excited, by a brusque and violent 

 movement. If the rheophore is placed over the apex of the supra- 

 clavicular triangle, the same movements are energetically produced 

 by the simultaneous contraction of the superior parts of the 

 trapezius and of the sterno-mastoid.* It seems to me to follow, 

 from this experiment, that the extreme excitability, which exists 

 only in limited portions of these muscles, is due to the presence of 

 the external branch of the spinal nerve. 



I proceed to show the dangers to which the patient is exposed 

 during faradization, if the operator is not acquainted with the 

 important fact just stated. At the beginning of my researches I 

 could not find in writers any warnings to put me on my guard 

 against the too numerous accidents that I have had to regret. 

 The following, among others, occurred during faradization of the 

 trapezius in a case of paralysis of the upper extremity. I had 

 directed a tolerably strong current upon the upper half of the 

 trapezius ; and then, jDassing suddenly to the external border of 

 that muscle, I placed a rheophore upon the apex of the supra- 

 clavicular triangle in such a manner as to touch, at the same time, 

 a portion of the upper half of the sterno-mastoid. The head 

 executed a movement of rotation ajud inclination so forcible that 

 the patient felt something crack, and had acute pain in the neck. 

 He also experienced stunning, and tingling in the extremities; 

 and required to be bled immediately. K the apparatus had been 

 graduated to its maximum, would there not have been an accident 



* The power that a nerve possesses, nerve is distributed to the upper half 



when artificially stimulated, to excite of the sterno-cleido-mastoid, and to the 



muscular contraction. | upper half of the trajiezius, especially at 



' The external branch of the spinal ; its external m irgin. 



