The chemical aspects of immunity / by H. Gideon Wells.

  • Wells, H. Gideon (Harry Gideon), 1875-1943.
Date:
1925
Catalogue details

Licence: In copyright

Credit: The chemical aspects of immunity / by H. Gideon Wells. Source: Wellcome Collection.

    134/262 (page 130)
    tion phenomenon then resolves itself into a consideration of the means whereby these two forces may be modified, increased or diminished. Agglutination occurs whenever the similar electric charges are decreased to amounts such that they will no longer overcome the pull of surface tension. Or conversely, surface tension may be increased until it over- comes the dispersion effect of the similar charges.” With these essential facts before us, we may pass to a more detailed consideration of The Mechanism of Agglutination This has been a fruitful field of research, in which the application of physical chemistry has been profitable. At first it was believed that the clumping was brought about by loss of motility, until it was found that non-motile bacteria were equally affected. Similarly, the hypothesis of adhesion of the flagella was disposed of.24 Paltauf considered that the specific precipitin produced by immunization carried the bacilli down in the precipitate formed. In support of this hypothesis is the observation of Scheller 25 that mixtures of typhoid bacilli and agglutinating serum lose their agglutinability by vigorous shaking, which may be interpreted as tbe result of disintegration of the agglutinating precipitate. Coplans 26 found the reaction of agglutinin with antigen associated with an increase in conductivity in the solutions, but whether this de- pends upon the agglutinin reaction itself, or upon associated processes, is questionable. Agglutinated bacteria can be separated from one another by the action of organic and inorganic acids, alkalies, acid salts, and by heating to 70° or 750, and after once being separated they cannot be reagglutinated by fresh serum.27 Neisser and Friedemann 28 found that if the bacterial cells were satu- rated with lead acetate, washed in water until all soluble lead was removed, and then treated with H2S, they were promptly agglutinated and precipitated, supporting other observations which indicate that pre- cipitation within the bacterial cells can lead to agglutination. This sort of agglutination is related to the process of formation of coarse flocculi in suspensions, and probably depends upon alterations in surface tension. Arrhenius 29 has attempted to show that the gas laws are applicable to the partition of agglutinin between tbe bacteria and tbe medium, which he compares to the partition of iodin between water and carbon disulfid. This view is not generally accepted. (See Craw24 and Dreyer and Douglass.30)