On the guaiacum process for the detection of blood in medico-legal cases : the antozone test / by Alfred S. Taylor.

  • Alfred Swaine Taylor
Date:
1868
Catalogue details

Licence: Public Domain Mark

Credit: On the guaiacum process for the detection of blood in medico-legal cases : the antozone test / by Alfred S. Taylor. Source: Wellcome Collection.

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

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    mixture which becomes rapidly blue by oxidation. All the salts of the peroxide of iron, including the sulphocyanate, operate in a similar manner, and at once render the guaiacurn blue. A very minute quantity of perchloride of iron will also cause this change in guaiacurn. The addition of any form of antozone is not necessary to produce this change of colour with the salts of iron, and it does not in any way increase it. Herein, then, lies the distinction. If the stain is on black cloth the guaiacurn solution should be added, with a little water to dissolve the ink, and the wetted stuff firmly pressed on white blotting-paper. If ink is present there will be a blue spot pro- duced, showing that the stain is probably owing to a salt of iron. The cloth, cut into fragments and macerated in distilled water, will yield a dark purple or bluish-black liquid, having the usual appearance of diluted ink, and wholly unlike blood. The guaiacurn solution added to this aqueous liquid, is pre- cipitated, and the precipitated resin rapidly acquires a blue colour, without the addition of peroxide of hydrogen. But iron may, in some instances, be present without being indicated by a stain or discoloration in the substance. Thus white or tawed leather produces a blue colour with guaiacurn and peroxide of hydrogen, very like that caused by blood : it also produces a blue colour, but more slowly, with guaiacurn alone. Alum and salt are used in the manufacture of this leather, and as when sold for manufacturing purposes these substances frequently contain a notable quantity of iron, the blueing effect on the guaiacurn may be owing to the presence of this metal thus transferred to the skin. Some kinds of white kid leather are open to the same observation: hence blood stains on white kid gloves should, if possible, be removed by water, and the red aqueous liquid separately tested. Some kinds of writing paper sized with sulphate of alumina containing iron, produce spots of a blue colour with the guaiacurn. When flour paste has been used in the dressing of the paper, the guaiacurn may be rendered blue by the gluten, which is incor- porated with the pulp. Filtering paper and calico are occasionally charged with flour-paste and in this case the guaiacurn might be coloured by coming in contact with gluten. Stains on weapons.—None but those who have frequently had occasion to examine weapons can be aware of the difficulties 3