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77, 127, 171, 363, 631
Industrial Accident Cases. E. 1. Carr. 0.
Multiple Fistula (of Anal Origin). E. G. Martin. 0.
Ear Disease in the Light of Medical History, Some Present
Eye, Ear, Nore and Throat Work, Some Practical Points
Fractures and the Application of Army Splints, Abstract of
Diagnostic Problems in. Bertrand L. Jones. 0. 427
Public Health Section of Annual Meeting
Serologie Examinations in Eye and Ear Cases. Don M.
Surgery of the Stomach. G, M. Todd. 0.
by the orthodiagraph whereby the pencil and the X-ray tube move together so that the out
line of the heart is traced by parallel rays. X-RAY METHODS OF DETERMINING
The finally corrected area is then to be comTHE SIZE OF THE HEART.
pared with the normal. It is here that the A. W. CRANE, M.D.
value and difficulty of Bardeen's researches beKALAMAZOO, MICHIGAN.
comes apparent. It was only after an immense
amount of work on the cadaver and on the livThe recent work of Professor Bardeen has ing, as well as an exhaustive examination of the emphasized anew the clinical importance of work of other investigators, that two tables heart-volume and the accuracy of its determina- were produced giving the normal relation of the tion by X-ray methods. Bardeen's first article heart silhouette area to the transverse diameter entitled "Tables for Aid in Determining the of the heart, to body weight, to heart weight, Size of the Heart by Means of the Roentgen to heart volume in diastole and to the height, Ray," appeared in the American Journal of for either sex, from childhood to old age. We Roentgenology for December, 1917. His sec- are thus enabled to estimate either heart-weight ond publication with full details of researches or heart-volume and compare either with the may be found in the American Journal of normal for a given height of the patient or for Anatomy, March, 1918. By this work a pro- a given weight, at any age. fessor of anatomy has made a notable advance After this brief general description we may in clinical diagnosis and has increased the pres- take up a few of the more important points tige of American roentgenology.
in greater detail. Bardeen's method is essentially the measure- The use of the planimeter is another examment of the parallel ray silhouette of the heart ple of the clever adaptation in diagnostics of an upon the X-ray plate and the comparison of instrument developed in a widely separated
measurement with normal values. To ob- science. By means of this instrument engitain the heart silhouette the sitting patient neers have long been accustomed to estimate the leans forward against an X-ray plate which is square area of any surface however irregular placed at an angle of 20 degrees. The anode
. The anode by simply tracing the outline 'by the pointer of the X-ray tube is placed 2 meters from the attached to an arm and then reading the square plate. An exposure covering not less than 11/2 inches or centimeters from a graduated disc seconds is then made, with breath held in mod- or wheel. It would be a practical impossibility erate inspiration. This insures the diastolic to compute the square area of the heart silhououtline of the heart in the antero-posterior posi- ette by any other method. The planimeter has tion. The silhouette thus obtained must be thus become a necessary part of a clinical completed by a line joining the apex of the equipment. heart with the right auricle and also above by The reduction factor of 6 per cent., whereby joining the right auricle with the line of the
the true parallel silhouette area is determined, left auricle. The area thus enclosed is readily is a value obtained by estimating the median estimated in square centimeters by means of plane of the heart from the front of the chest a planimeter.
as one-third the distance from front to back This area is larger than the true size of the of the thorax. Bardeen arrived at this averheart because the X-rays diverge from a focal age by a large number of measurements in the point. A reduction of 6 per cent. is therefore dissecting room and by a process of mathemade to give the true parallel ray silhouette. matics from stereoscopic plates of living subThe result is then comparable to that obtained jects. He was able to verify the work of Albera.