Plant analysis : qualitative and quantitative / by G. Dragendorff ; translated from the German by Henry G. Greenish.

  • Dragendorff, G. (Georg), 1836-1898.
Date:
1884
Catalogue details

Licence: Public Domain Mark

Credit: Plant analysis : qualitative and quantitative / by G. Dragendorff ; translated from the German by Henry G. Greenish. Source: Wellcome Collection.

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    the methods of examination hitherto devised, either for the estimation of a single constituent or for the Separation of several substances contained in a jjlant, I hoped to succeed in inducing others to condiict investigations in a department of Chemistry at present so much neglected; and it was in that hope that I decided npon the Compilation of this work. In it I trust to he able to show that for the separate estimation of many substances we have methods at oiir disposal which, in point of accuracy, are nearly abreast of the processes employed for the determination of mineral constituents, and that we can often obtain results really serviceable in the investigation of the more important component substances contained in a plant. I especially hope to succeed in showing that analyses of plants possess in one respect an advantage over the analyses of minerals, inasmuch as it often happens, in examining mixtures or conglomerates of several Chemical individuals, that in the latter case a much less satisfactory insight into the Constitu- tion can be obtained than in the formen The elements, for instance, of which a granite is composed can easily be deter- mined by inorganic analysis, but it is exceedingly difhcult to ascertain with exactitude in what quantity each separate mineral occurring in the granite is present. But in the analysis of vegetable substances the endeavour is made from the outset to separate the different Chemical individuals from one another, and by the use of various solvents this is fre- quently possible. In this respect, therefore, the analysis of a plant can often be made more complete than that of a mineral. § 2. The object that I have sought to attain in this work was the Compilation of a method of analysis applicable to the qualitative and quantitative examination of vegetable substances of both known and unknown composition, and of an introduc- tion to the qualitative and quantitative determination of the various more important constituents of plants with which we are at present acquainted. I need scarcely observe that I have given the füllest possible consideration to the question as to which tissues of the plant contain the various constituents, and have therefore, for that purpose, made use of microchemical analysis. With reference to the arrangement of the matter in the work, I would remark that in the method of analysis contained in