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By the power of distinction method, in which the discriminability of letters of different degrees of contrast is determined at various illuminations, Edmund and Clemmesen examined the adaptation faculty (aptation) of the retina in a group of pregnant medical patients and concluded that the number of cases of dysaptation in this class of patients had decreased during the past year, probably because of the popular agitation concerning vitamins stirred up by the press and as a result of the vitaminization of margarin. A nine months investigation of a selected group of prisoners in the state prison in Nyborg was done by the same method to determine the adequacy or inadequacy of the prison diet with respect to vitamin A. It was concluded that a diet containing 1,374 international units of vitamin A daily is adequate to obliterate seasonal oscillations in the power of distinction. The ordinary prison diet (1,225 units
On Deficiency of A Vitamin and Visual Dysaptation. II. JAMA. 1938;111(1):90. doi:10.1001/jama.1938.02790270092039
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