Injurious Effects of the Roentgen Rays Page 7

the x-rays themselves. He endeavored to show that these particles had so accumulated in a given case as to produce an ostitis and periostitis, acting like foreign bodies in the tissues. He produced in evidence of this a skiagraph of the part taken after the injury was developed, which he said showed a marked increase in the density of the bones. He laid no emphasis on a chemical analysis of the exfoliated skin, which, however, gave a negative result.

Campbell Swinton, Esq., of London, writes : "Cathode rays are generally believed in this country to consist of atoms or molecules of residual gas, which, being similarly electrified to the cathode, are repulsed by the latter, and travel at an average velocity not much less than one-twentieth that of light, the velocity depending upon the exact potential of the cathode and the molecule at the moment the latter leaves the former, and also upon the degree of the exhaustion of the tube, upon which depends the free path of the molecules, that is, the distance a molecule can travel without coming in contact with another molecule."

It seems strange that Dr. Gilchrist should have so confused the material particles of the cathode rays, which, as we have seen, can be nothing but residual gas, with the unique theory of Tesla, who spoke of metallic particles of the electrodes - aluminum or platinum, as the case might be - which he believed were projected through the walls of the tube and into the densest tissues. Tesla has also informed us (12) that if the part of the body exposed to the x-rays be placed between a metal plate and the tube, the injury would be on the side of the part on which was the metal plate. But that if a thin plate of aluminum, which is practically transparent to the x-rays, or a sheet of wire gauze, be placed between the tube and the exposed part, and at the same time the metal screen be electrically connected with the ground, the disturbance to the tissues will be avoided. His latest suggestion (13) is that it is possible for the "electro static influence" which generates the ozone to "decompose the sodium chloride in the tissues, thus giving rise to irritants." It would appear that his statements of the violet halo or brush-discharge around the tube connected with the practical value of metal screen in dispersing the injurious agents when electrically grounded, and its concentrative power, if placed on the far side of the part and not grounded, point directly to the action of electric currents and nothing else. Dr. Charles a Lenard (14) states directly that the "burn" is the result of induced electric currents in the tissues, which will be induced capable of destroying their vitality, if the patient is approached sufficiently near to the x-ray tube.

Dr. Monell speaks of the electrical energy transformed into heat by resistance of dry skin, etc., as causing dermatitis and inflammation. Professor E. Dorn (15) has demonstrated that x-rays do exert very slight heat effects, and he has measured their quantity, but this element is of so small amount as not to be appreciable.

A remarkable fact in nearly all cases of the "burn" is that no sensations of heat are felt at the time of exposure, and only in some cases is there noted any immediate symptoms whatever, as of "a sense of prickling heat, or a tingling followed by itching;" but there is uniformly no sensitiveness or pain. Another characteristic is the time which elapses from the exposure to the appearance of the first symptoms - usually a week to nine or ten days, or even a month or more in some cases. These facts have called forth the statement from several authorities (16) that the lesion is "not a burn," inasmuch as the accepted definition (17)