Notes on physiology / by Henry Ashby.

Henry Ashby

Date:: 1889

Credit: Notes on physiology / by Henry Ashby. Source: Wellcome Collection.

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$treated with dilute caustic potash and gently warmed, some of its properties undergo change. The alkaline solution will no longer be precipitated by boiling. It is precipitated on neutralisation with acids, and is soluble in excess of the acid. It is not precipitated on neutralisation in presence of the alkaline phosphates. Casein.—This substance closely resembles alkali albuminate, but differs from it in containing sulphur. It can readily be prepared from milk by saturating with magnesium sulphate, or by acidifying and gently warming ; it is precipitated when milk comes in con- tact with the walls of the stomach. Acid Albumin.—If albumin in solution is treated with HCl or other acids, it undergoes a change in its properties. It is no longer coagulated by heat. It is precipitated on neutralisation with an alkali, and is redissolved by excess; its precipitation is not prevented by alkaline phosphates. It is pre- cipitated on boiling with lime-water. If muscle be dissolved in dilute HCl, a body termed syntonin^ closely resembling, if not identical with, acid albumin, is formed. 2. Globulins.—These bodies differ from the albumins in being insoluble in water, precipitated by CO2, or on saturating their solutions with NaCl. They are converted into acid albumin by HCl. They are soluble in dilute solutions of NaCl, the solution being precipitated by heat. They include {a) globulin, (l?) paraglobulin, (r) fibrinogen, {d) myosin, {e) vitellin. {a) Globulin exists in the crystalline lens, and closely resembles paraglobulin in its properties, but differs from it in not assisting to form fibrin. {b) Paraglobulin occurs in blood and serum, and in smaller quantities in some of the tissues. It gives rise to fibrin when mixed with any fluid, as hydrocele fluid, containing fibrinogen.$

Notes on physiology / by Henry Ashby.

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