Repository: UIHistories Project: Board of Trustees Minutes - 1880 [PAGE 119]

EXTRACTED TEXT FROM PAGE:

117 The gram of dried cane reserved for water and ash was heated in an oven at 110° C. until its weight was constant. It was then ignited and the ash weighed. The ten grams for the estimation of sugar, etc., were macerated with water in a mortar, the water decanted, and this process continued several times, the decanted liquids being filtered by Bunsens' method, and finally the residue was thrown on the filter and washed until the filterate measured one litre. 100 c.c. of this solution were evaporated nearly to dryness on a water-bath, then the desiccation completed by passing a current of dry air upon the residue by means of an aspirator, the temperature of the substance in the meantime ranging between 90° and 100° C. The residue was then weighed, incinerated, and weight of ash noted. Albuminoids.—400 c.c. of the aqueous extract were evaporated to a sirup on the water-bath, calcined gypsum added, the whole then dried and the residue ignited with soda-lime. 500 c.c. of the aqueous extract were rapidly evaporated nearly to dryness, and the residue exhausted with alcohol of 87 per cent, by repeated boilings with fresh portions of the solvent as long as it was colored. The liquids were filtered, the residue thrown upon the filter and washed with hot alcohol, and the washing added to the filtrate. Water was added to the filtrate, the alcohol expelled by heat, and then the solution diluted to 200 c.c. Grape Sugar.—100 c.c. of this solution were reserved for the estimation of grape sugar. The remainder was acidulated with dilute sulphuric acid, and boiled to convert the cane into grape sugar. Cane Sugar.—The cane sugar was then estimated with Tehling's solution, as usual. The residue insoluble in alcohol was dried at 100° C, weighed, and then incinerated. This ash and the soluble albuminoids were subtracted from the total amount of residue, and the remainder estimated as gum and vegetable acids. The residue left after extracting the ten grams of cane with water was washed with alcohol acidulated with sulphuric acid to dissolve the albuminoids, transferred to a beaker, and diluted to 200 c.c. 5 c.c. of normal sulphuric acid were added, and the whole boiled for an hour on the water-bath, then filtered through Bunsen's filter. The filter was also cut into shreds and boiled with water containing one per cent, of sulphuric acid, to dissolve any starch remaining on it. After filtering, the two filtrates were added, and the starch estimated from an alliquot portion by conversion into glucose.