Physiology of digestion and the digestive organs / by Arthur Gamgee.

  • Gamgee, Arthur, 1841-1909.
Date:
[1884?]
Catalogue details

Licence: Public Domain Mark

Credit: Physiology of digestion and the digestive organs / by Arthur Gamgee. Source: Wellcome Collection.

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    are similar, &c. According to Musculus and v. Mehring in both cases there are formed achroodextrins, maltose, and a little grape-sugar. Roberts has found that the action of pancreatic diastase on starch mucilage increases in speed from zero to 30° C. From this to 45° C. the rate of action continues steady. Above 45° the action becomes slower and slower and ceases between 60° and 70°. We have seen that within a certain range of temperature, the rapidity of the action upon starch increases. Tempera- ture and all other conditions being exactly similar, the rapidity of the action will depend upon the quantity of enzyme present. This is well brought out in the following remarks (Roberts). The speed at which a given quantity of starch is trans- formed by diastase depends essentially on the proportion of ferment brought to act upon it. In the above experiments (experiments in which a minimal quantity of diastatic solu- tion acted upon starch) the proportion of diastase was very minute in comparison with the amount of starch, and the action went on slowly for forty-eight hours. But if we re- verse these proportions and mix a small amount of starch with a large amount of diastase the transformation is in- stantaneously accomplished. If a test-tube be half filled with an active extract of pancreas and a few drops of starch mucilage be quickly shaken therewith, you cannot detect the reaction of starch or dextrine in the mixture, however prompt you may be with the testing—the transformation has followed on the admixture as instantaneously as the explo- sion of the charge follows the fall of the trigger. Between these extremes there are all gradations. Roberts has estimated that pancreatic diastase is able to transform into sugar and dextrin no less than 40,000 times its own weight of starch. Had I sufficient time at my disposal I should enter at length into the question as to whether the diastatic ferment of the pancreas exists preformed in the cells of the gland, or whether these contain an antecedent or so-called zymogen