ELECTRIZATION BY REFLEX ACTIQN. 127 



§ II. — Excitation by eeflex action in passing induced 



CUREENTS FROM THE MOUTH TO THE ANUS. 



I. Physiological action. 



The already described methods of faradization by reflex action 

 do not strongly excite the spinal cord, excepting at the points of 

 origin of the brachial and lumbo-sacral plexuses. There is yet 

 another procedure which produces a more general reflex excita- 

 tion of the cord. I refer to the method by placing one rheophore 

 of an induction apparatus in the mouth, and the other in the 

 anus ; the already mentioned mode of application of Leroy 

 (d'EtioUes). The following is a brief account of the experiments 

 by which I have studied the physiological action that it thus 

 produces: — 



Experiment 1. — I have already stated that in 1853, I repeated, upon a 

 horse, the experiment of Leroy "ndth an induced current. The ciirrent was 

 feeble ; but strong enough for its reflex action to produce general tetanoid 

 contractions in the limbs and trunk, dming which the respiratory move- 

 ments and the action of the heart were not siispended. 2. I repeated 

 analogous experiments upon rabbits ; and many w^ere made, in my presence, 

 in the laboratory of my friend M. Liegois. With an excessively feeble cur- 

 rent there was no appreciable result beyond a slight contraction of the 

 tongue and of the muscles of the face. The force of the extra current of 

 my instrument, which had been originally at its minimum, and not only 

 so, but had been passed through a stratum of water in the moderator to 

 be hereafter described, was then progressively increased until it produced 

 tetanoid contractions of the muscles of the trunk and limbs. Neither the 

 respiration nor the heart's pulsation were arrested, but they were suspended 

 diu'ing one or two seconds. The experiment, repeated twice ui^on the same 

 rabbit, and for from twenty to thirty seconds each time, gave always the 

 same results. But, when the strength of the current was so much increased 

 as to tetanize and render immovable the waUs of the thorax, a needle thrust 

 into the heart also ceased to oscillate. 



We see, therefore, that when the rheophores are placed as 

 described, a feeble induced current of rapid intermission can 

 produce tetanic convulsions of the limbs and trunk, evidently by 

 reflex action of the whole cord, without arresting either the cir- 

 culation or the breathing. 



Another fact not less important follows from these experiments, 

 namely, that this mode of faradization produces a comparatively 

 feeble reflex excitation of the medulla oblongata. Notwith- 

 standing the general tetanic convulsions that are produced, the 

 respiration and the heart's action, although suspended for one or 

 two seconds, have continued during the twenty or thirty seconds 

 during which the experiment lasted ; and it was only to be noticed 

 that these movements were increased in rapidity. 



Every experimenter knows how feeble a current, applied to the 

 exposed pneumogastric, will arrest the heart and the respiration ; 



