THE COMPLETE APPARATUS, The apparatus for the production of the X-rays, not including the source of elec tricity, is shown by Fig. 919. On the right hand side is the induction coil, and on the left the glass tube held in its wooden clip. The connecting wires are supported upon glass posts, so that the current shall not stray from its appointed path. These are the essential things for X-ray work, but the coil can be replaced by a static machine as already explained. In addition to these articles, a fluoresc2ut screen will be required for direct observa tion, and photographic plates or films for records of the effects produced. It is, perhaps, hardly necessary to caution anyone accustomed to deal with electrical apparatus that great care must be exer cised in using an induction coil, even of moderate capacity, for it can give a terrible shock. By using the posts made of glass, the connecting wires can be kept away from one another, and from other parts of the apparatus, otherwise they are likely to spark across and give trouble.
The discharge must take place through the vacuum tube, and not outside it. Another caution is necessary in dealing with X-ray apparatus. Continued exposure to the action of the rays leads to a destructive action on the skin and nails. Cases are known in which the nails have actually been lost through this action, and sore ness due to protracted exposure in surgical cases has more than once re sulted in a claim for damages in the law courts. An excessive exposure, adopted for experimental purposes, has even led to serious injury and death. It is a peculiarity of these evil effects that they do not become apparent till some time afterwat ds.