HANDBOOK FOR BIO-CHEMICAL LABORATORY. 73 



2. Dissolve 173 grammes Rochelle salts in 350 c.c. water, 

 adding 600 c.c. of a caustic soda solution of a specific gravity 

 of 1.12, and dilute to 1000 c.c. with water. For use mix equal 

 parts of the above solutions and dilute with an equal volume 

 of water. 

 Fehl ing's Solution. 



10 c.c. 0.0500 gramme dextrose, laevulose, or invert sugar. 



10 c.c. 0.0475 gramme cane-sugar (after inversion). 



10 c.c. = 0.07143 gramme milk-sugar (lactose). 



10 c.c. = 0.0807 gramme malt-sugar (maltose). 



FLEISCHL'S Reaction (Bile Pigments). Treat the urine 

 with a concentrated solution of sodium nitrate and add con- 

 centrated sulphuric acid by means of a pipette. This latter 

 sinks to the bottom of the test-tube and produces the colora- 

 tion, as in Gmelin's test. 



FROHDE'S Reaction (Proteids). On heating a solid proteid 

 with sulphuric acid containing molybdic acid a beautiful dark 

 blue color is produced. 



FROHN'S Reagent. Treat 1.5 grammes freshly precipitated 

 bismuth subnitrate with 20 c.c water, heat to boiling, and 

 then add 7 grammes potassium iodide and 10 c.c. hydrochloric 

 acid. 



FURBRINGER'S Reagent (Albumin). Gelatin capsules con- 

 taining the double salt of mercuric chloride and sodium chlo- 

 ride with citric acid. 



FURFUROL Reaction (Proteids). On heating proteids with 

 sulphuric acid furfurol is produced, which may be detected 

 by various means (see MOLISCH, SCHULTZE.) 



GALLOIS'S Test (Inpsit). Evaporate the inosit solution to 

 incipient dryness and moisten the residue with a little mer- 

 curic nitrate solution, when a yellowish residue is obtained on 



