Volume 1

The tannins : a monograph on the history, preparation, properties, methods of estimation, and uses of the vegetable astringents with an index to the literature of the subject / by Henry Trimble.

  • Trimble, Henry, 1853-1898.
Date:
1892-1894
Catalogue details

Licence: Public Domain Mark

Credit: The tannins : a monograph on the history, preparation, properties, methods of estimation, and uses of the vegetable astringents with an index to the literature of the subject / by Henry Trimble. Source: Wellcome Collection.

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    long and from one to two inches thick. Some are long and slender, others are nearly as broad as long. In weight they vary from a few ounces to over a pound. The exterior of the root is from a reddish-brown to a nearly black color, depending upon its age, and upon the amount of iron in the soil. Late in the summer a number of buds appear on the crown end of the tubers, ready for growth after the winter rains. The indi- vidual tubers appear to reach their full size at the close of the first season, but they continue to live, producing new roots and new plants each season, for several years. The roots of a year's growth are a little more firm in texture than a potato; but when they finally die they become dry, hard, and nearly black throughout. In this condition they are as hard to cut as a piece of wood; and there is a large increase in the amount of coloring matter. By boiling, the root becomes softer, but does not break open and fall to pieces as the potato. The young roots are nearly white in the interior. As they grow older they become dark yellowish red, from the development of coloring matter within the cells. The following description of the structural character- istics of the root is taken from the Bulletin of the Arizona Experiment Station referred to above: The tissue of the root is mostly of large celled parenchyma, with a few wood cells and ducts scattered about here and there, but mostly toward the centre of the root. This tissue develops from a thick layer of cambium located in the nearly mature root at about a quarter of the distance from the epidermis to the centre. A rapid development of permanent parenchyma tissue takes place at either side of the cambium zone; how-