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

having different functions, in virtue of a difference in the apparatus on which they are distributed, and in the centres on or from which they act and react, you will, I think, arrive at re- sults as comprehensive as the fivefold division affords, but much more comprehensible, and much more applicable to every-day practice. The physiology of the nervous system must be care- fully studied if you would practise medicine and surgery suc- cessfully. Sciatica. Let us here examine the affections of the great ischiatic nerve, because they may be regarded as a type of local nervous diseases in general. Sciatica, in the first place, must be con- tradistinguished from simple nervousness, (in itself considered,) as exalted nervous function, or nervous derangement, or neu- ralgia, or perverted conditions, sensations, and motions. This malady takes its name from the great sciatic (ischiatic) nerve, which is the seat of the affection. The sciatic, which is the largest nerve of the human body outside of the brain and spinal cord, having extensive distribution of its branches, en- ables us to observe and study the phenomena of nerve inflam- mation and the neuralgic condition more definitely here than when similar affections are seated in smaller nerves. This great nerve trunk is formed, we must first observe, by the union of the terminal branches, or roots, of the lower portion of the spinal cord, (cauda equina^) which pass from the lumbar and sacral ganglia out of the pelvis, by the ischiatic notch, as a very large nerve cord. It then takes its course down the outer and back part of the leg to the foot. When the pain is seated in the bottom or outer edge of the foot, we know it is in the ulti- mate twigs of the great sciatic nerve. If the pain is chiefly in the inner and anterior side of the leg, or about the inner ankle, then we know it is rather in the ultimate ramifications of the crural (femoral) nerve. (See p. 477, and Notes in Appendix.) Sciatica, (not sciatic neuralgia,) in its true and less frequent forms, is a real inflammatory disease, (neuritis,') generally seated in the nerve, or, rather, in and about the sheath of that portion