Identifikator: americanxrayjour1418unse (Treffer finden) Titel: American X-ray journal Jahr: 1899 (1890er Jahre) Autoren: Themen: Röntgenaufnahmen Herausgeber: St. Louis: American X-Ray Publishing Co.

Identifier: americanxrayjour1418unse (find matches)
Title: American X-ray journal
Year: 1899 (1890s)
Authors:
Subjects: X-Rays Radiography
Publisher: St. Louis : American X-Ray Publishing Co.
Contributing Library: The College of Physicians of Philadelphia Historical Medical Library
Digitizing Sponsor: Open Knowledge Commons and the National Endowment for the Humanities



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n of thefield by the localizing apparatus. The only remaining source oferror is the unconscious motionof the eye. This is a frequentsource of error, which I haveseen entirely destroy the image ~Pof an object whose presence asucceeding series of observa-tions absolutely demonstrated. Thebest method of overcoming this error is,as many writers have shown, the clos-ure of the e)es. Attempts to fix the eye upon a definite-point are generally failures, as the eyedoes not sustain the strain readily, andunconscious movements, as in winking,are certain to occur. With the eyelidsclosed, the eye remains quiet, and itsposition can afterward be readily deter- mined by observing the prominence ofthe cornea through the eyelid. The great advantage of this method isits simplicity and infallible mathematicalaccuracy. The method ol employing the appa-ratus is the following : The patient isseated in a chair, the yjke fastened tohis shoulders, and the upright frameplaced tightly against the temple, with 3
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FIG 1 the head held in position by the bandattached to the frame. The fixed pointis marked and the tube adjusted in aplane perpendicular to the photographicplate at the known point. The plate isthen placed in position. The tube uponthe adjustable arm is placed at an angleappropriate to the individual case, theangle noted, and an exposure made ; asecond plate is then substituted, the an-gle changed and noted and the exposure THE AMERICAN X-RAY JOURNAL. 467 made. These exposures are repeated atdifferent angles as often as may be nec-essary ; two, however, usually suffice togive absolute localizations. After theplates are developed the distance of theshallow of the foreign body from the•known point is carefully determined, andwith the angle and known side in eachobservation give the data upon whichthe calculations are based. The practical determination of the lo-cation of the foreign body is greatly sim-plified by substituting for the mathemat-ical calculations the following graphicmet