The modified Holtz or Toepler-Holtz electrical machine is now used to procure all of the nerve and muscular effects hitherto obtained by faradic electricity, and also therapeutical results of a very striking kind. It has long been known that chorea and other nervous affections may be readily cured by static electricity, but a remarkable extension has been given to the subject by late discoveries. Chorea is now treated by the "electric bath," sparks being drawn from the spine. If the Holtz machine is used, sparks can readily be drawn through the clothing by presenting the brass knob along the spine. The results, which have been so long obtained at Guy's Hospital by this mode of electrical applications, are now generally conceded. It seems to be the most successful method of treating this disease. Neuralgia is now promptly relieved in most instances by insulating the patient and drawing sparks from along the trajectory of the nerve affected. The pains of progressive locomotor ataxia are much benefited in the same way, and it is said the disease itself is arrested. Amenorrhoea, other conditions favorable, is quickly cured by sparks, or a shock sent through the pelvis. The general nutrition is greatly promoted by electrization by sparks.

The Toepler-Holtz machine may, by connecting the interior of one condenser with the exterior of the other, be utilized to procure the muscle and nerve reactions of the faradic current.

Trouvé's Polyscope, referred to above, will probably be largely employed in the future, for the purposes of illumination. Suitable throat and other mirrors, platinum knives, and loops, are furnished with the instrument for illumination of the cavities, and for the various caustic operations. It is very powerful, occupies but little space, and promises, when certain mechanical defects are overcome, to fulfill more perfectly than any other apparatus the requirements of a surgical gal-vano-caustic and a medical illuminating apparatus.

The Roentgen or X-Rays. It has long been known that ordinary white light is a combination of light, heat, and chemical rays, the red end of the solar spectrum being the least, and the violet the most refrangible. In the violet end of the spectrum, and beyond, are contained the chemical rays. The ethereal vibrations, or impulses, occurring in this position, are not the regular, successive movements that produce light, but a less orderly disturbance of the ether. These so-called X-rays have the power to penetrate many bodies opaque to ordinary light—as flesh, wood, paper, and other fibrous materials. It has been found that substances and structures of considerable thickness and high atomic weight are less permeable to these rays. For example, when the rays are passed through the extended hand, the muscles, connective tissue, and fat are transparent to them, while the bones are opaque, and hence appear in distinct outlines on the photographic plate.