Journal . astase soon loses its fermenting power, and becomesalmost useless within a month after it has been pre-pared. The author has adopted a modification of Maerekers1. in which the conversion of the starch is carriedout under pressure, and the cellulose is almost com-pletely separated. The apparatus employed is thatdevised by Soxhlet for the estimation of starch, andcousists of a copper vessel F. 25cm. in diameter and28cm. deep, tinned on the inside, and supported on ironfeet. The disc b is supported by three feet, which restupon a sieve e placed upon the bottom of the digester ;iu b ther
Journal . astase soon loses its fermenting power, and becomesalmost useless within a month after it has been pre-pared. The author has adopted a modification of Maerekers1. in which the conversion of the starch is carriedout under pressure, and the cellulose is almost com-pletely separated. The apparatus employed is thatdevised by Soxhlet for the estimation of starch, andcousists of a copper vessel F. 25cm. in diameter and28cm. deep, tinned on the inside, and supported on ironfeet. The disc b is supported by three feet, which restupon a sieve e placed upon the bottom of the digester ;iu b there are seven openings 5 which serve as support 8lor stioii. glass Basks of about 150cc. capacity. Wateris poured into the vessel until it stands about 1cm. above the false bottom e, and then b (which is also Idled withwater up to the level of the holes b) is finely-powdered substance is placed iu the Flasks,shaken up with a few cc of distilled water, and lOOcc. Of hot distilled water added of. meal or Hourshould lie taken, and 2—5gnns. of seeds, such n> pepperor cacao. After thorough shaking the flasks are un-corked and placed in the holes ,:, the cover is screwedtightly on, and the temperature raised to 140—150 C ,which corresponds to a pressure of four atmospheres, asindicated by the barometer. By proper regulationthe temperature can be kept fairly constant for threeand-a half hours ; the steam is then allowed to escapeby the Bafetj valve, and the cover is removed. Thecontents of the flasks are filtered while hot with afilter-pump, and the residue on the lilter washed withhot water until the filtrate gives no reaction withiodine. The filtrate (measuring .{00—350CC.) is heatedwith 20cc. concentrated HC1 in a flask with invertedcondenser on a water bath for three hours, filtered,neutralised with caustic soda, and made up to oOOcc. ;the dextrose formed is estimated by titration withFehlings solution. The percentage of starch is calcu-lated by the formulae
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
