Current, 110 volts direct. Crookes tube was placed directly over the dorsal vertebrae, the anode forming an angle of about 20 degrees with the plate. The tube was distant from the plate about 22 inches; the amount of voltage to the primary coil during exposure could not be registered exactly (25-40 volts) due to the sudden switching on and off of the indicator; amperage about 20-25. The exposure was made while the patient had lungs deeply inflated by air during inspiration. The time of exposure varied between 12 to 22 seconds. Developed in Metol Hydroch. developer, came up slowly, continued this process about 25 to 30 minutes, negative has not been intensified in bichloride solution.

The Skiagram. No. 1. The skiagram exhibits, considering that the time of exposure was very short, a great deal of contrast, bones not showing well, on account of being underexposed. The lung, due to the contained air, appears to be emphysematous.

The blurred effect of the ribs is due to a sudden jumping of the patient during the switching off and on of the current. The difference in the shadows may be observed where the intensifying screen was used.

This position is best for skiagraphing the heart, the organ being thereby brought near to the plate, a matter highly essential. The size of the heart as seen on this skiagram is 16 cm. as measured from apex to base. The position is apparently normal. The borders of the heart are not sharp being blurred more or less, a condition undoubtedly produced by the intensifying screen.

The longitudinal shadows, three-quarters of an inch in the short axis and six inches in the long axis on both sides of the upper thorax, are produced by the respective scapulae. It may be observed that these shadows do not interfere with those of the ribs and lung.

The normal position of the diaphragm on the right side is slightly higher than on the left, and there was no movement of it as is normal during respiration. The upper margins. therefore, are clear cut and sharply defined.

The following table indicates the different experiments performed on the same individual, employing different positions. different interrupters and the use of the intensifying screen. The changing of the position has no apparent effect upon the skiagram, so far as time of exposure is concerned.

Patient, man 22 years old, 5 ft. 5 in., weight 140 lbs. Apparatus, 15-in. spark producing Ruhmkorff coil, current 110 volts direct, 10-cell storage battery.

I am of the opinion that soon I will be able to register all the movements of the heart (cycle of diastole and systole), the lungs, the ribs, the excursion of the diaphragm, on a series of consecutive plates to be shown in rapid succession as in kinetoscopic pictures.

1831 Chestnut St., Professional Building, Philadelphia.

A SIMPLE DEVICE TO AID X-RAY TECHNIQUE. By O. Shephard Barnum, M. D.

Of Los Angeles, California.

The following suggestions are offered with the idea that it may be of interest to readers of this journal to know of a simple, home-made device which will materially assist in making the work of the operating room uniform.

The use of the hand or arm of the operator with a fluoroscope as a guide in estimating the penetrating power of the ray is greatly to be condemned, both as unscientific and dangerous. To do away with this habit I have for a long time used the following described simple gradient, which I have found highly satisfactory and efficient. The idea is not original but commends itself on account of its simplicity.

Ask any glazier to supply eight pieces of medium weight window glass cut 11⁄2 in. wide, the shortest piece 2 in. long and the longest 9 in., the intervening ones varying I in. in length. Cut from a piece of sheet brass some small figures about 1⁄2 in. in height, from 1 to 8. Lay the pieces of glass in

No. 1.

Place on the

regular order like accompanying cut (No. 1.) exposed part of the longest piece of glass the metal number 1, and so on up, the number representing the number of thicknesses of glass through which the ray penetrates. Bind them longitudinally by a strip of 11⁄2 in. adhesive plaster; take a piece of I in. plaster and bind around each step, being careful not to lap. Over all paste a tough paper carefully and neatly, and the device is complete.

This gradient will tell instantly by the fluoroscope just what degree of penetration a tube has at any particular moment, and the variation in tubes can be measured by the distance of the gradient from the tube. In short, the metal number distinctly discerned at a certain number of feet from the tube will represent the penetrability of the ray from that particular tube.

With this device at hand, and a preliminary knowledge of

the office equipment, viz., a familiarity with the characteristics of the various tubes, it is a simple matter indeed to duplicate any desired ray. It is wise to use one tube as a standard for comparison with all the others, and a few radiographs made with this gradient will determine their relation correctly enough to prevent serious errors in case of accidental loss of a tube, or other emergency. In using the rays for therapeutic purposes the more accurate we may be in their application, both as to abundance and penetrating power, the better our results will be. A change from one tube to another is in my estimation a much-to-be-regretted necessity unless the relation of those tubes may be determined, approximately at least.

No. 2.

The left picture was taken with a tube of higher vacuum than the right picture. Note that this is shown not only by the shadows of the bones, but quantitatively by the penetration of the glass slips.

The accompanying cuts will give further insight into the value of this little device in everyday work. Cut No. 2 shows the difference between two tubes for radiographic work under exactly the same conditions, and on one plate, thus insuring equal development. These two halves of the one plate were made with different tubes under like conditions of distance, time and exciting power.

Cut No. 3 represents the gradient skiagraphed by the same tube under exactly similar conditions with the exception of a difference in speed of interruptions by the mercury jet. The side marked I which is much more distinct for the higher numbers of the gradient, was made with the slower interruptions; side II being exceedingly rapid. This cut is presented only to show in an interesting way the fact which several operators have learned from experience-that the slower the interruptions in coil work, the better will be the results in radiographs. I have simply introduced a rheostat in the main circuit with motor on the interrupter, and am enabled in this way easily to control the number of interruptions for any particular work I wish.

picture with a higher speed.