Proteins : lectures given in the United States of America in 1924 / by S.P.L. Sørensen.

  • Sørensen, S. P. L. (Soren Peter Lauritz), 1868-1939.
Date:
1925
Catalogue details

Licence: In copyright

Credit: Proteins : lectures given in the United States of America in 1924 / by S.P.L. Sørensen. Source: Wellcome Collection.

    57/174 (page 31)
    At the Carlsberg Laboratory in Copenhagen we have, dur- ing the past ten years, carried out a series of experiments on the osmotic pressure of hens’ egg albumin, horse serum al- bumin, and horse serum globulin at or near the isoelectric re- action of these proteins, which, at any rate in the case of the two first, corresponds approximately to pH=4.8. I shall describe the results of these measurements after first giving a brief account of the methods employed. A detailed descrip- tion of these methods, as well as of the experiments with egg albumin, has already been published1; the experiments with albumin and globulin from horse serum on the other hand, have not yet been made public. The Method Employed Diagram 1 shows the apparatus we use for the measure- ment of osmotic pressure. The osmometer consists chiefly of a collodion tube A, placed on a glass collar, B, into the neck of which a ground glass tube is fitted so as to be perfectly watertight. This glass tube is narrowed a little above the ground part to a capillary tube, divided into millimeters with zero at the glass collar B as starting point. The protein solution to be measured (the inside solution) is poured into the collodion tube, the ground glass is fitted on, and filled by means of a capillary pipette, until the inside solution reaches a little way up along the milli- meter scale. The tap C is then closed and the osmometer placed in the outside solution, which is in a Dewar vessel standing in a cylinder glass, this again being placed in a well regulated water thermostat. The thermostat is not shown in 1 Compt. rend. Lab. Carlsberg 12, 262 [1917].