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.

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    sugar (a misture of equal parts of dextrose or grape-sugar and Igevulose or fruit-sugar) before it can be made available for nutrition. The yeast plant is no exception to this rule; and when placed in a solution of cane-sugar it is under the necessity of transforming that compound into invert-sugar before it can use it for its profit in fermentation. This transformation is efiected by a soluble ferment attached to the yeast cell, which can be dissolved from it by water. We shall see later on that a similar ferment exists for a similar purpose in the small intestine of animals—having the same pro- perty of changing cane-sugar into invert-sugar. Even among the higher plants exterior digestion is not quite unknown. The function may be said to be foreshadowed in the excretion of an acid fluid by the rootlets of some plants which serves to dis- solve and render absorbable the mineral matters in their vicinity. But genuine and most remarkable examples of this type of digestion occur among the so-called insectivorous plants, of which Mr. Darwin has given so interesting an account. In the sundews, the plant, by a peculiar mechanism provided on its foliage, seizes the insects which fortuitously alight on its leaves. A stomach is extemporised around the prey, into which is poured out a digestive fluid. The prey is digested, and the products absorbed, in essentially the same manner as in the gastric digestion of animals.