This is prepared from purified aldehyde-ammonia, CH3CH(OH)NH1. The recrystallised substance is ground in a mortar with dehydrated ether several times, the ether being decanted off after each grinding; the residue is then dried for about twenty-four hours in a desiccator over concentrated sulphuric acid.1 1.386 Grams, corresponding with 1 gram of aldehyde, are weighed out into a 100 c.c. flask, and dissolved in 50 c.c. of strong alcohol (96 per cent.). To the solution are added 227 c.c. of N /1 alcoholic sulphuric acid: this precipitates the ammonia as sulphate. The flask is now filled up to the 100 c.c. mark with more of the strong alcohol, and a further 08 c.c. of the alcohol is added to compensate for the volume of the precipitated ammonium sulphate. After being shaken and allowed to settle for twenty-four hours, the solution is filtered. It contains 1 gram of aldehyde per 100 c.c., and from it standard solutions containing 01 and 001 gram are prepared by dilution with 50 per cent. alcohol. The 01 per cent. solution can be used in the estimations instead of the 0 01 per cent. solution, but as the quantities required will now usually be tenths of a cubic centimetre there is less accuracy in the measurements.

Gayon And Schiff's Reagent

To prepare this, a 01 per cent. aqueous solution of fuchsin is made, and 150 c.c. of it are added to 100 c.c. of a saturated solution of sodium bisulphite. Fifteen c.c. of 66 per cent. sulphuric acid are added, and the whole made up to 1 litre.