Applied medical chemistry : a manual for students and practitioners of medicine / by Lawrence Wolff.

  • Wolff Lawrence.
Date:
1885
Catalogue details

Licence: Public Domain Mark

Credit: Applied medical chemistry : a manual for students and practitioners of medicine / by Lawrence Wolff. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    part in chemical relations, and is used variously to bring about reduction and decomposition, but as its scope embraces the consideration of other physical principles, the student is referred to the text-books on Physics for the details of the manipulations depending on it. Light and optical phenomena are utilized for chemical pro- cesses in a way that makes their influence of great import- ance. Spectroscopy.—Light in passing through a prism is dis- solved into various colors termed a spectrum. Spectra of dif- ferent substances produce variations in the positions of certain bands according to their locality. This phenomenon proves of importance to the medical chemist in the determination of blood, as oxyhaemoglobin, reduced haemoglobin, alkaline hae- matin, etc. Polarimetry.—A ray of light in passing through certain media is divided into two, and thus doubly refracted it is termed polarized. The determination of the influence of a body on polarized light, with a suitable instrument for this purpose, is of great importance, as many bodies have distinct analytical char- acters in this respect. This instrument consists of a polarizer, an analyzer, and a container. In the measure that optically active substances necessitate the rotation of the analyzer to the right or left, for extinction of different tints they are termed dextro-gyrous (+) or Icevo-gyrous (—). The specific rotary poiver of a body expressed in degrees and tenths thereof is ascertained by dissolving a certain quantity in a definite quantity of solvent( and noting the degree of rotation for a certain column. If [«] is the specific rotary power looked for, w the weight of the sub- stance contained in I c.c. solvent, and / the length of column, the product of the latter two by division into the degree of rota- tion, a, observed would give specific rotary power, [«] = With monochromatic light the specific rotary power is ex- pressed by [<?]D. Knowing the specific rotary power of a body, the amount of substance contained in a certain column of solution can be demonstrated by the following formula, IV = ^ / This is of special value in determining the amount of sugar in