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

which must have been frequently observed in cases of disease or injury affecting the spinal marrow; namely, that the power of motion is commonly lost before sensation, or is destroyed to a comparatively greater degree. The explanation of this seems to be, that the morbid action affects the column of motion, sit- uated superficially, before it can reach those of sensation, which are placed more deeply in the cord. In regard to the proofs which may be drawn as to the exact columns of the spinal mar- row, which confer sensation from tracing the roots of the fifth cerebral nerve to their origins, some dissections described by Sir Charles Bell, in his later papers to the Royal Society, seem to be of peculiar interest. The fifth nerve, he says, re- sembles the spinal nerves in having two roots, one of which bestows motion, and the other sensation. It arises at the base of the brain, from the side of the pons varolii, apparently at a very remote distance from the spinal marrow. It is well known, however, to anatomists that the larger root, proved to be that which gives sensation, has its real origin from a point which may be considered the commencement of the spinal marrow. On following the thin, flat, ribbon-like band of medullary matter, which forms the proper root downwards through the medulla oblongata, Sir Charles Bell was satisfied that it did not pass in the direction of the posterior column, and has no connection there. He observed that it took a more lateral course, and dis- appeared in a tract which he regarded as the continuation of the posterior lateral column. From the same column lie also found posterior roots of the spinal nerves arising, and he conse- quently inferred that it is the posterior lateral column, and not the main posterior, which is the source of sensibility in the great spinal cord. The " cilio-spinal region'''' is that portion of the spinal column included between the seventh cervical and sixth dorsal vertebrae. This term originated with Professors Waller and Budge, who first observed that when this region of the spine is strongly excited by Faradaic current, the impression is transmitted through the cervical sympathetic nerve and ganglia, (the roots of which emerge from that part of the spinal cord,) it then 20