of a permanent record for future use. It was thought that the fluoroscope would supplant that skiagraph, but in most cases the plate will catch the details of a picture in less time that it takes to do so with the fluoroscope. A method of photographing the fluoroscopic shadow has been introduced, with the idea of lessening the length of exposure. This has not given pictures with as good definition as the direct method, and it has been but little used. For the detection of foreign bodies in certain localities the fluoroscope is sufficient, but as their removal is often difficult the surgeon usually prefers a picture to which frequent reference can be made; for the observation of moving objects, such as the heart and diaphragm, the fluoroscope alone is serviceable.

The importance of skiagraphy in anatomical study cannot be overestimated. The gross anatomy of the body is fairly well understood; still the accurate delineation of the bones, and especially of joints, is necessarily schematic, as drawings can only be made after a partial or even complete dissection, which must alter to come extent their normal relations. Skiagraphs show with great accuracy the normal positions of bones in the formation of joints; as they are true representations of undisturbed relations, they should be extensively adopted in illustrating anatomical works in place of the schematic pictures now employed. Although the additional information to be obtained in this way cannot be great, that which is gained is of the utmost importance; particularly is it of value in the examination of bones and joints during growth. The ossification of bones has a fairly uniform rate, and text-books give the time when the centers of ossification first appear and approximately the time when it is completed. This process is subject to wide variation in individual cases. The x-ray furnishes us with definite information regarding the ossification of bone, and we are able by this means to note any departure from the normal. We are thus placed in possession of an important diagnostic aid, and one which gives us information not heretofore obtainable. It is possible that we may be able to recognize with greater certainty that protean disorder, rickets, having as its most characteristic feature delay in the ossification of the

bone. The opposite condition, of too early union of central and distal ossification, resulting in the early stoppage of growth, will be revealed by the skiagraph. In short, we may confidently look for a flood of light to be thrown on all anomalies of bone nutrition.

One of the earliest applications of the x-ray was to the detection of foreign bodies. It is in these cases that some of the most brilliant achievements have been reached. The power of the ray in depicting a foreign body imbedded in the tissues depends upon the greater density of the former. The general rule is that the greater the specific gravity of an object the more marked the shadow-or stated in other words, the higher the specific gravity, the greater the absorption. This rule has some exceptions. The heavy metals and their salts give dense shadows. Iron, glass and stones are the substances most commonly introduced into the body which are detectable by the x-ray. In a large proportion of cases the foreign bodies become encapsulated, and cease to be a source of danger. In all recent cases, however, where a foreign body can be accurately located in an accessible portion of the body, it should be removed. If the foreign substance causes pain, interferes with locomotion, or leads to suppuration, it should be removed, even though an extensive operation is required.

Fractures and dislocations offer a wide and brilliant field for investigation. By this means we may study a fracture before it is reduced, and afterward we can see how perfectly it has been done. The latter will often surprise the surgeon. In many cases where there is every appearance of perfect reduction the fluoroscope or skiagraph will reveal marked discrepancies in the apposition. It is needless to comment on the importance of early and correct knowledge of the position of fragments after fracture. In addition, there are fractures in the long diameter of bones and near joints, in which the most experienced surgeons may err, and which are at once revealed by the skiagraph. In many dislocations the value of this method is very great. Especially is this true in dislocations of the knee. These are often attended by so much inflammation and swelling that it is practically impossible to say when perfect reduction has been secured. In

these cases a skiagraph can be made which will give accurate information without pain or special inconvenience to the patient.

Skiagraphy will undoubtedly develop important forensic relations. The value of the skiagraph in evidence has not yet been determined, but as the method is based on rigid principles of physics, there can be no question of its ultimate recognition in our courts. Especially will this prove to be the case in the treatment of fractures and dislocations which furnish the basis of the larger number of malpractice suits. We feel safe in predicting that it is only a matter of time until the treatment of most fractures of the extremities will be guided and controlled by the skiagraph.

An important field for the x-ray is in the diagnosis of diseases of bone. Tuberculosis and other diseases alter the normal lines and the density of these structures so that we can often determine the extent and character of the disease. A bone tumor, being of less density than the surrounding tissues, would present less resistance to the passage of the rays, and in consequence could be recognized. Chronic inflammation with its consequent structural alteration can easily be recognized. Osseous deformities, both congenital and acquired, will furnish an important field of investigation.

Thus far we have considered mostly surgical affections, but it is reasonable to suppose that valuable data may be obtained by the x-ray in internal medicine. As tissues differ in structure and chemical composition, a certain limited differentiation is obtained in the skiagraph. The lungs, for example, because of their contained air allow the rays to pass readily, consequently they are shown as light shadows, and can be differentiated from the heart, dia

phragm, and liver. The heart with its dense muscular structure, rich in salts, throws a dark shadow by which its border is easily recognized. Aneurisms and tumors containing blood are easily identified when situated in less absorbent tissues like the lungs. Skiagraphs often show the skin and fatty tissues, and occasionally muscles may be outlined. These details are usually more apparent in the negative than in the print. These facts lead us to hope for great advances, that will come in the future with a better understanding of the process, and improved technique. At present the practical range of application seems to be limited to a differentiation of bony structure, calculous deposit, solid tumors, and foreign bodies.

With perfection of technique a skiagraph ought to reveal everything visible with the flouroscope, except in the case of movable shadows, as of the heart and diaphragm. Fluroscopy requires much less time, but an exceedingly practiced eye. Therefore some observers prefer and have been much more successful with the screen than others.

The left border of the heart, the diaphragm and the liver can be readily seen, also moderately extensive consolidations in the lungs, pleuritic exudations and aneurisms; but as to the diagnosis of atheromatous cardiac arteries, mere pleuritic adhesions, the accurate size of the kidneys, and many similar complicated conditions, proof must be brought before these statements can be accepted as of positive diagnostic value.

The great drawback to the screen is its phosphorescence; this blurs outlines and produces false shadows. Mr. Edison is recently quoted as having removed this fault in part.

Skiagraphy is much more difficult and subtile in its medical than in its surgical application. The latter has been fairly well exploited in the short time since the discovery of the Roentgen ray, while at present more attention is being paid to the medical possibilities.Medicine.