Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.

ing at its opening or discontinuance, and not at its closure, if the current is the inverse or up-running, i. e., towards the spinal marrow and brain. M. Nobili distinguishes from such trials, as he thinks, some five stages or degrees of irritability that may be found in the same set of nerves in the same animal. The first stage is where the contraction appears in four conditions, as both with the vp- running and dotea-running currents, and at the closing and opening of the circuit. The second stage is where one of these is wanting; i. c., where there is no contraction from the closure of the up-running current. The third is where two of these are wanting ; i. e., where also the contraction is wanting at the open- ing of the down-running stream. The fourth is where but one contraction remains, and that is at the closure of the direct or down-running current. The fifth is where there is no sort of contraction in any case, either at closure or opening of the cir- cuit, nor at the up or down traversing current. We can state it, in short, thus : — 1. Contraction at closure and opening of both up and down currents. 2. Contraction lost at closure of the inverse current. 3. Contraction lost at opening of the direct current. 4. Contraction lost at all but at closure of the direct. 5. Contraction lost at all and under all circumstances. By means of a proper current of galvanism, and under this rule, he thinks that we may be enabled to judge of the state of irritability of any nerve trunk ; indeed, that this becomes a kind of by-law for the operator, not only for judging of new cases, but also in determining the advance or retrograde effects of the electro-medical treatments. But we must bear in mind the actual difference there is between irritability and capability: the former admonishes us to be careful, the latter is the cure. TVe do not usually observe any sensible contraction of mus- cles when under the steady running of a feeble current of gal- vanism. But this, as say Remak, De la Rive, and others, does not prove that there is not a certain effect being produced on the nerves by the steady and gentle inworking of this current.