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

is applicable to all the nerves of the human organism. Even with the motory nerves it appears to he a rule that here, also, the excitability decreases in proportion as it is made farther from the brain: thus tonic contractions can be produced on the human hand with so much the more facility the nearer the elec- trodes are placed to the brain over the trunk of the nerve medi- anvs on the upper arm. Labile stream workings are those that are produced by means of small metallic electrodes covered with wet wash-leather, flan- nel, or linen, and which are either hitched along over the surface, say every five seconds or so, on and in the course of the nerve, or held more-and-lcss firmly against the skin, so as to cause in either case frequent or constant changes in the density of the current. Stabile stream workings are those used for down-toning — i. e., for purposes exactly opposite to excitability. For this pur- pose we must always choose large, soft, and moist electrodes, which must be gently and very gradually applied, and then held with an even pressure and moderate current, and then removed again, after the time, say from one to five minutes, with the same degree of precaution. There is a nice difference, also, to be observed between the en- trance and leaving muscle contractions and the closing and open- ing contractions. These first, as we have seen, occur at the in- stant the current of the battery begins to course through the nerve and flesh ; while the others occur at the instant the cur- rent is interrupted, opened, or broken, (as these latter terms are synonymously employed.) But the term " entrance contrac- tion " refers to the putting on the electrode, while the current is still running, and the term " leaving contraction " refers to the removal of the electrode while the current is still running. On the other hand, the term " closing contraction " refers to the closing or making the circuit, as by the metallic switch contact of the key-board ; and the " opening contraction" refers to the opening or breaking of the circuit by opening the same metallic key of the key-board. The latter division is stronger in effect than the former, probably because the electro-tonic state is more