The effect on the molecular concentration and electrical conductivity of muscle extracts of removal of the proteids / by G.N. Stewart.

  • Stewart, G. N. (George Neil), 1860-1930.
Date:
[1899?]
Catalogue details

Licence: Public Domain Mark

Credit: The effect on the molecular concentration and electrical conductivity of muscle extracts of removal of the proteids / by G.N. Stewart. Source: Wellcome Collection.

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    [.Reprinted from the Journal of Physiology. Vol. XXIV. No. 6, August 21, 1899.] THE EFFECT ON THE MOLECULAR CONCENTRATION AND ELECTRICAL CONDUCTIVITY OF MUSCLE EXTRACTS OF REMOVAL OF THE PROTEIDS. By G. N. STEWART, Western Reserve University, Cleveland, U.S.A. (.Preliminary Note.) Several investigators have tried to determine whether proteids exert a sensible osmotic pressure by observing the freezing point of solutions of such proteids as egg-albumin before and after heat- precipitation of the proteids. The result in most cases has been negative. In the course of some work on the proteids of muscle, I had the opportunity to determine whether any changes took place in the freezing point and electrical conductivity of various extracts after removal of the proteids. It seemed to me that such observations might throw light on the obscure relations of salts to proteids in solutions where both exist together, and especially on the relations of salts to the globulins which they hold in solution. Further, it suggested itself that information as to the nature of the proteid which is precipitated from a muscle extract at a given temperature might be obtained by observing whether the changes in the freezing point and conductivity after its precipitation indicated that salts had been held in combination with it in the solution or not. For instance, it might be expected that a globulin would hold the salts more firmly than an albumin or hold a larger amount of salts in combination. Different globulins, too, might be combined with different quantities of salts; and from the amount of the change of freezing point or conductivity caused by the precipitation of given amounts of globulins at different temperatures, it seemed possible to learn something as to their chemical or chemico-physical resemblances or differences. If, for example, the precipitation of a certain amount of a globulin coagulating at 47° were found to cause a greater or a smaller change in the freezing point or conductivity than the precipitation of the same