Report on the progress of physiological botany during the year 1841 / by H.F. Link. Translated by E. Lankester.

  • Heinrich Friedrich Link
Date:
[1845]
Catalogue details

Licence: Public Domain Mark

Credit: Report on the progress of physiological botany during the year 1841 / by H.F. Link. Translated by E. Lankester. Source: Wellcome Collection.

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    act at all, or at all events only in a trifling degree, upon the former, tannic acid contracting it a little ; the latter, how¬ ever, is not only contracted by it, but combines with it. This excellent work presents decided answers on many dis¬ puted points. I may here be permitted to add something respecting the starch in plants. I have illustrated the changes of the gra¬ nules of starch in the 16th Table of the leones Anatomicae Botanicce. The granules of potatoes T^re burst by warm water, and yielded a thick fluid mass, which assumed a blue colour on the application of iodine, the same as the enclosing integument. It follows from this, that each granule of starch contains a thick fluid kernel, as Raspail asserted, although the integuments consist of many layers, as may indeed be distinctly seen in many granules of starch, just as Fritzsche first observed. As this thick fluid kernel assumes a blue colour on the application of iodine, like the integument, there is no reason to doubt that it consists of any thing else than a mass of amylum. It is an ordinary occurrence, that this mass is changed into gum or dextrine, by being strongly heated, or by a lengthened rubbing with water, as Raspail applied it, and a similar transformation takes place on the more usual application of nitric acid. The experiment should be per¬ formed as soon as the bursting has taken place, in order to avoid any change occurring in the starch. The integument of the granules is frequently found torn after germination ; see fig. 9 and 10 of the same table, compared with fig. 8. Unformed thick fluid starch I first found in the bulbous-formed roots of Balep, subsequently also in the bulbous-formed roots of the common Orchis latifolia^ before and after blossoming, as is seen in fig. ] 3 of the same table. Later, I also found amylum in the roots of Orchis pyramidalis, and in the roots of Orchis latifolia, long after blossoming. As usual in granules. Roots of Salep are also met with, that contain granules of starch. It seems, therefore, that the unformed matter is capable of transforming itself into granules. A thick fluid mass, which cannot be coloured by iodine, mixed with large granules of starch, is also found in the seed of Phaseolus 408
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