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possibly have been affected by the galvanism acting through the 

 superjacent spinal column. In order to eliminate the vagi com- 

 pletely, I divided in another rabbit all the soft parts in front of the 

 spine, except the trachea and oesophagus, at the level of the cricoid 

 cartilage, having previously cut each carotid artery between two liga- 

 tures. The incisions were carried fairly down to the bodies of the 

 vertebrae, and outwards beyond the tips of the transverse processes, 

 so as to ensure the section not only of the vagi and their branches, 

 but also of the sympathetic cords, with any filaments of those nerves 

 which they might contain. Also the poles of the battery were 

 fixed to the spinous processes of the seventh dorsal and first lumbar 

 vertebrae, so as to avoid all possibility of direct action of the gal- 

 vanism upon either the vagi or other cardiac nerves. Feeble cur- 

 rents being then transmitted, diminution of the number of beats to 

 the extent of two to four in ten seconds occurred in several succes- 

 sive trials, the results being so constant as to leave no doubt that 

 they were produced by the galvanism. 



It may appear almost incredible that such extremely mild galvanic 

 currents, applied through the spinous processes of the posterior dorsal 

 region, should be capable of thus affecting the heart ; but that their 

 effects were really very considerable, was clear from the further pro- 

 gress of this experiment and from others somewhat similar, which 

 showed that this apparently trivial stimulation gradually exhausted 

 the part of the nervous system through which the heart is acted on 

 by the cord. Thus, in one case, currents only just perceptible to the 

 tongue, transmitted for about thirty seconds at a time through the 

 lower cervical and upper dorsal regions of the spine, at intervals of 

 nine minutes on the average during two hours and twenty minutes, 

 produced at first decided increase of the heart's action, but during 

 the last hour failed to affect it at all. The strongest possible action 

 of the battery which, as proved by other experiments, would, at the 

 outset, have entirely arrested the cardiac movements, was then set on, 

 but with no effect whatever on the organ. 



When partial exhaustion has occurred, a much stronger galvanic 

 stimulus is required, to produce the same effect upon the heart, than 

 at the commencement of an experiment ; and thus an action of the 

 battery which, when first applied, causes marked diminution in the 

 number of beats, may after a while come to have the opposite effect, 



