The proteids of serum / by W.D. Halliburton.

  • William Dobinson Halliburton
Date:
[1884?]
Catalogue details

Licence: Public Domain Mark

Credit: The proteids of serum / by W.D. Halliburton. 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.

    36/48 (page 184)
    Sheep’s serum was sliaken with magnesium sulphate, and the precipitate of serum globulin so produced was filtered off; the filtrate was shaken for eighteen hours with excess of sodium nitrate ; the precipitate produced was collected at intervals in three lots; the final filtrate contained no proteid. The precipitates were washed with water saturated with both salts and dissolved by adding water. The first precipitate collected after three hours’ shaking was washed and dissolved; by fractional heat-coagulation coagula were found to occur at 73o_4° and 83“ C. The second precipitate, collected after five hours’ more shaking, was similarly found to coagulate at 77“ C. The third, collected after ten hours’ more shaking, was very small in quantity and coagulated at 77“ C. We here see, as in the case of double saturation with magnesium sulphate and sodium sulphate, that both the varieties of serum albumin in sheep’s serum are precipitated equally by this method, only the pre- cipitation of that coagulating at 83“ C. is accomplished sooner because there is not present so much of it as of that which coagulates at 77“ C. It will be seen in the above experiment that the first precipitate con- tained a proteid which coagulated at 73“—4“, not at 77“'C. as one would expect: this lowering of the temperature of coagulation is due to the admixture of a certain amount of sodium nitrate with the liquid. That sodium nitrate has a very marked effect in lowering the temperature of coagulation of proteids, especially when present in large quantities, is shown by the following experiment: Sheep’s serum was first saturated with magnesium sul})hate and filtered ; the filtrate was saturated with sodium nitrate and shaken for three hours; by this means a large amount of the serum albumin was j3recipitated, but still a large amount remained in solution; the preci[)itate was filtered off, and the filtrate was found to be faintly alkaline. This was heated (no acid being added), and at 45” C. opalescence appeared, 55“ C. abundant flocculent precipitate, soluble in water, 77“ C. small amount of precipitate. In a portion of this liquid rendered faintly acid in the usual way, the following took place on fractional heat coagulation: 60“ C. opalescence, 65“ C. flocculent precipitate, 77“ C. slight amount of flocculent ])recipitate. In another specimen diluted with an equal amount of water, the following was the result: