The clinical application of the Röntgen rays.

Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: The clinical application of the Röntgen rays. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    efficient, and was used in most of ray work. It is probable that when the vacuum-tubes are improved the Rontgen action may be obtained by the use of much less expensive apparatus than that here employed. It is hardly necessary to statethat any voltaic cells or storage-batteries may be used as the source of current, and that care must be taken that no higher electro-motive force is present in the circuit containing the primary coil than that which the coil is designed to bear. This is gen- erally not greater than 12 to 15 volts, and with smaller coils may be less. It is thus manifestly impossible to use the current from a city supply directly with the coil. If it is used at all, a shunt must be introduced. The best form of shunt is the proper number of cells of a storage-battery, which can be receiving their charge at the same time that they are set- ting the coil in action. The vacuum-tubes used in my first trials were in the collection at Princeton ; after they broke down others obtained from Queen & Co., Philadelphia, were found equally serviceable. My experience agrees with that of others, that the ordinary Crookes' tubes differ very much in their efficiency. Of those in the Princeton cabinet, only three or four, when tested by the skiascope, showed that they were furnishing an abundant supply of the Rontgen rays; and most of those on sale in the shops are worthless. The cause for the superior excellence of some tubes over others seems to lie largely in the different thickness of the glass wall. This has been stated by Mr. Edison, and an observation which I made suggested the same explanation to me. One of the Crookes' tubes with which I worked had the form of a nearly spherical bulb with two conical projections. Four aluminum electrodes were inserted into this bulb, two at the ends of the conical projections, the other two, one a straight wire, the other a flat disk, through the wall of the bulb. Those who are familiar with the ordi- nary form of the Crookes' tubes will recognize this at once as the one furnished as*a companion to another of similar form, but less highly exhausted, to show the difference between the Crookes' cathode-action and the ordinary stratified discharge. If the flat disk-electrode of this tube was made the cathode, a patch of green phosphorescence appeared on the opposite wall of the tube. This spot I made the source of the Rontgen rays in my first attempt to get a photograph ; though suffi- cient was obtained to show the Rontgen effect, yet the action was very feeble; and when the tube in this condition is examined by the skia- scope it is evident that the tube is not doing efficient work. Other tubes in which the cathode-rays travel long distances from flat electrodes before they fall on the glass show similar feeble action. When any one of the three wire electrodes was made the cathode the characteristic green phosphorescence appeared around it; in the case of the electrodes in the projections the phosphorescence was very brilliant and confined