Uffelmann reagent

Uf·fel·mann re·a·gent

(ūf'ĕl-mahn),
a solution prepared by adding a 2% solution of phenol in water to aqueous ferric chloride until the solution becomes violet; this turns lemon yellow in the presence of lactic acid, assumes an opaline tint in butyric acid, and is decolorized by hydrochloric acid.
[J. A. C. Uffelmann]

Uffelmann,

Jules, German physician, 1837-1894.
Uffelmann reagent - a 2% solution of phenol in water and aqueous ferric chloride.
Uffelmann test - determines amount of lactic acid in gastric fluid.