Outlines of practical physiology : being a manual for the physiological laboratory, including chemical and experimental physiology, with reference to practical medicine / by William Stirling.

  • William Stirling
Date:
1902
Catalogue details

Licence: Public Domain Mark

Credit: Outlines of practical physiology : being a manual for the physiological laboratory, including chemical and experimental physiology, with reference to practical medicine / by William Stirling. Source: Wellcome Collection.

    37/690 (page 7)
    HOI and dilute alkalies. Tlie solutions are not coagulated by heat. (1) Alkali-albumin or Alkali-albuminate. (а) To dilute egg-albumin add a few drops of o-i p.c. NaHO, and keep it at 40° C. for 5 to 10 minutes = alkali-albumin. Boil; it does not coagulate, and is alkaline. (б) Colour some with litmus, and neutralise carefully with o’i p.c. HOI or H2S04 = a precipitate on neutralisation, which is soluble in excess of acid or alkali. (c) Repeat (6); but, before neutralising, add sodium phos¬ phate solution (10 p.c,). The alkaline phosphates prevent precipitation on neutralisation, until at least sufficient acid is added to convert the basic phosphate into acid phosphate. The solution must be decidedly acid before a precipitate falls. (d) Precipitate by saturating with crystals of NaCl or MgS04. (e) Lieberkiihn’s jelly is a strong solution of alkali-albumin. To undiluted egg-white add strong KHO. The whole mass becomes a jelly, so that the tube can be inverted without the mass falling out. (f) Liberation of sulphur. Boil a strong solution of alkali-albumin with lead acetate solution = black precipitate of lead sulphide. (2) Acid-albumin [or syntonin]. Preparation. (A) To dilute egg-albumin, add cri p.c. H2S04, and warm gently for several minutes = acid-albumin. (B) To finely-minced well washed muscle, e.g., of frog or rabbit, add ten volumes of dilute HC1 (4 c.c. of acid in a litre of water), allow it to stand for several hours and stir it frequently; filter, the filtrate is a solution of a globulin combined with an acid—syntonin. (C) Allow concentrated HC1 to act on fibrin for a time, and filter. (D) Dissolve myosin in excess of 1 p.c. HC1, and after a time neutralise the solution with sodium carbonate. (E) To undiluted egg-white, add acetic acid = a jelly of acid-albumin. XJse the clear filtrate from (A) or (B) for testing acid reaction. (а) Boil; it does not coagulate. (б) Add litmus solution, and neutralise with very dilute NaHO = a precipitate soluble in excess of the alkali or acid. (c) Repeat (6), but add sodium phosphate before neutralis¬ ing; acid-albumin is precipitated on neutralising. Thus sodium phosphate does not interfere with its precipitation. (d) Add strong HN03 = a precipitate which dissolves on heating, producing an intense yellow colour. (e) It is precipitated by saturation with neutral salts, e.g., NaCl, MgS04, (NH4)2S04, like globulins.