The American journal of the medical sciences (1827)
[Thorofare, N.J., etc.] Charles B. Slack [etc.] · leaf 119
1874 ] Loring, New Modification of the Ophthalmoscope. 115 The intervals between the focal lengths of these glasses are small enough to fulfil every requirement in ophthalmoscopy, without the perplexing resort of adding and subtracting vulgar fractions with comparatively high … denominators. If required, however, it is very easy to vary the focal inter- val in all the stronger, and in many of the moderately strong glasses, that is, from J- to J^. This is done by the observer simply withdrawing his head half an inch from the ordinary place of examination. If, for example,…
Medicine
Internet Archive · Smithsonian Libraries · Public domain (published before 1931). Free to use for anything.
