On certain proteid and albuminoid reactions and their significance / by J.W. Pickering.

  • Pickering, John William.
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: On certain proteid and albuminoid reactions and their significance / by J.W. Pickering. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    the ammoniacal solution would produce a white flaky precipitate of calcium phosphate which looks extremely like a proteid coagulum‘. It therefore devolves upon Grimaux to shew that he has removed all phosphates from his solutions which in the short account of his experiments published in the Gomptes Rendus he has neglected to do. Until he has done this, his observations are open to doubt. A detailed account of the experiments would therefore be valuable. I can however confirm Grirnaux’s statement that the “ Colloide amidobenzoique ’ gives a blue-violet solution with copper sulphate and potash. With Gnezda’s reaction it gives a pale yellow, and with cobalt sulphate and potash a purple-brown, changing rapidly to a red- brown. XIV. Summary of Chief Results. 1. The preceding observations tend to shew, that excepting Frohde’s and Axenfeld’s reactions, each of the characteristic proteid tests examined corresponds to changes set up in definite molecular groups in the proteid molecule. 2. That cobalt salts and potash give delicate and distinctive colour reactions with proteids, proteoses, and peptones (proteid = heliotrope purple ; proteoses, and peptone = red brown). 3. That characteristic colour reactions are given with cobalt sul- phate, caustic potash and the following albuminoids, gelatin, keratin, elastin, colloid substance of the thyroid gland, and mucin. 4. That the same reagents give colour reactions with nitrogen katabolic compounds and certain bodies of allied chemical constitution, e.g.—biuret, alloxan, uric acid, xanthine, hypoxanthine and murexide. 5. That the colour plays obtained with gelatin are in the same spectral order as the colour plays obtained with alloxan, biuret, and allantoin. 6. That it is not improbable that the colour reactions of proteids, albuminoids, proteoses, and peptones, with the salts of cobalt, nickel and copper together with potash are due to the chemical group (CONH) common to the former bodies. 7. That it is not improbable that the difference between a proteid * The resemblance in physical property to albumen is so great that it has been substituted for that body in certain technical processes.