On the digestive ferments and the preparation and use of artificially digested food : being the Lumleian lectures for the year 1880, delivered before the Royal College of Physicians / by Wm. Roberts.

  • Roberts, Sir William, 1830-1899.
Date:
1880
Catalogue details

Licence: Public Domain Mark

Credit: On the digestive ferments and the preparation and use of artificially digested food : being the Lumleian lectures for the year 1880, delivered before the Royal College of Physicians / by Wm. Roberts. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    22/114 (page 22)
    Diastase lias only a feeble action on tlie unbroken starch granule, even at the temperature of thebody. In the lower animals, and in germinating seeds, the starch granule is probably attacked in the first instance by some other solvent, which penetrates its outer mem- branes, and thus enables the diastase to reach and act on the starchy matter contained within. By the aid of heat and moisture in the process of cooking, the starch granule is much more effectively broken up. Its contents swell out enormously by imbibition of water, and the whole is converted, more or less completely, into a paste or jelly or mucilaginous gruel. It is in this gelatinous form exclusively, or almost exclusively, that starch is presented for digestion to man. The digestion of starch is accomplished by the saliva and pancreatic juice, both of which are rich in diastase. Diastase also exists abundantly in the liver, and in smaller quantities in the intestinal juice, in the blood, the urine, and apparently in all the interstitial juices. Diastase from all these di- verse sources appears to act substantially in the same manner on starch, changing it by a progres- sive hydrolysis into sugar and dextrine. If the action of a fluid containing diastase— say saliva or extract of pancreas—on starch paste be watched, the first effect observed is the Hque- faction of the paste and the production of a diffluent solution. This change is eff'ected with great celerity—in two or three minutes the stifi paste