The American journal of roentgenology, radium therapy and nuclear medicine (1906) (14570840440)

Identifier: americanjournroen08ameruoft (find matches)

Title: The American journal of roentgenology, radium therapy and nuclear medicine

Year: 1906 (1900s)

Authors: American Radium Society American Roentgen Ray Society

Subjects: Radiotherapy X-rays

Publisher: Springfield, Ill. C.C. Thomas

Contributing Library: Gerstein - University of Toronto

Digitizing Sponsor: University of Toronto

Text Appearing Before Image:

are readv to see the fluorescent screen to advan-tage. The more visitors who come at onetime the better, as then there is competitionbetween them as to who will first developsufficient sensitiveness of his retina to be thefirst to use the instrument. The retinometer consists of three lumin-ous discs, the largest is a triangle, the me-dium sized one is oval and the smallest oneis a circle with a diameter of about i mm.These three discs are kept in the dark by acovering flap which is kept in apposition •Read at the Twenty-first Annual Meeting of The American Roentgen Ray Society, Minneapolis, Minn., Sept. 14-17, 1920. 76 A Retinometer with the discs by means of a spring. A stringa yard long is attached to the flap. By puUingthis string the discs are exposed. The freeend of the string has a luminous tassel forthe convenience of finding it in the dark. Touse the instrument the observer picks up thetassel and pulls on the string; holding thetassel in his hand, keeping the string taut he

Text Appearing After Image:

Fig. I. Retinometer Closed. places the tassel againsthis temple, his eyes arethen at a distance ofone yard from the in-strument and the lumi-nous discs are exposedto his view. He is nowin a position to gaugethe sensitiveness of hisretinae. Most observersare able to see the lumi-nous tassel at once. One who has come into the dark room from outof doors will be unable to see the large lumi-nous triangle. But by going close up to it hewill see it and he can then recede from itgradually, keeping it in view as his retinagrows more sensitive. When he can just seethe large triangle alone at the distance of thelength of the string (one yard) he will be un-able to see the next brightest spot—the oval,but by now going close up to it he will be ableto see the oval and by the time he can see theoval at the distance of the length of thestring, he is ready to begin to use the fluor-escent screen. Until he can see the triangleand the oval in the dark his eyes are not in afit state to look at the sc

the american journal of roentgenology radium therapy and nuclear medicine 1906 book illustrations x ray roentgen rays medical devices medicine medical therapy images from internet archive minneapolis minnesota

1906

University of Toronto

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