The chief use of the method up to the present time, besides determining the diseases, injuries, and abnormities of bone, has been in determining with absolute accuracy the presence of foreign bodies, especially of needles, bullets, or shot and glass. It is often extremely difficult to decide whether a needle is actually present or not. There may be a little prick of the skin, and no further positive evidence, as the needle is often imperceptible to touch. The patient, when cross-questioned, is frequently doubtful whether the needle has not dropped on the floor; and it might be, in some cases, a serious question whether an exploratory operation to find a possible needle might not do more harm than the needle. Moreover, though certainly present, to locate it exactly is often very difficult; and even after an incision has been made, though it may be embedded in a hand or foot, it is no easy task to find it.
[Illustration: FIGURE 9.--SKIAGRAPH OF A HUMAN FOOT, SHOWING THE DEFORMITY IN THE LAST TWO TOES CAUSED BY TIGHT BOOTS.
(Skiagraphed by Mr. Sydney Rowland, and published in the "British Medical Journal.")]
The new method is a great step in advance in the line of precision of diagnosis, and, therefore, of correct treatment. About half a dozen cases have already been reported in the medical journals in which a needle was suspected to be in the hand or the foot, and, in some instances, had been sought for fruitlessly by a surgeon, in which the use of the X rays demonstrated absolutely, not only its presence, but its exact location, and it has then been an easy matter to extract it. So, too, in an equal number of cases, bullets and shot have been located, even after a prior fruitless search, and have been successfully extracted. Figure 6 is the skiagraph of the hand of a cadaver which shows a needle deeply embedded in the thumb, and also two buck-shot, which were inserted into the palm of the hand through two incisions. It will be noticed that their denser shadow is seen even _through the bones_ of the hand themselves, for the hand was skiagraphed palm downward.
Professor von Bergmann of Berlin has uttered, however, a timely warning upon this very point. In many cases, after bullets or shot have been embedded in the tissues for any length of time, they become quite harmless. They are surrounded with a firm capsule of gristly substance which renders them inert. In 1863, soon after I graduated in medicine, I remember very well assisting the late Professor S.D. Gross in extracting a ball from the leg of a soldier who had been wounded at the Borodino, during Napoleon's campaign in Russia. It lay in the leg entirely harmless for almost fifty years, and then became a source of irritation, and was easily found and removed. There are many veterans of the Civil War now living with bullets embedded in their bodies which are doing no harm; and there is not a little danger that in the desire to find and remove them greater harm may be done by an operation than by letting them alone.