Effect of lonization on Antiseptics.

Abstract

Results from our studies on antiseptics lead us to believe that the theories which are commonly advanced to explain such action are not satisfactory. To set forth the significance of our results it appears necessary to consider briefly the experimental basis of current theories.

Experiments performed by Krönig and Paul 1 on the antiseptic properties of HgCl₂ and the effects of NaCl upon its germicidal properties led these investigators to the general hypothesis that the ionized part of the toxic molecule is the part that penetrates the cell and kills the organism. Their results would lead one to believe that if anything is added to a solution which decreases the amount of ionization of a germicidal molecule, the germicidal value is decreased. They concluded this from the fact that when NaCl is added to solutions of HgCl₂ the germicidal value of the solution is decreased. They explained this by assuming first that the Hg ions are the toxic elements, and second, that by the addition of the common Cl ion the ionization of the HgCl₂ was lowered. Because salts of mercury ionize very poorly, and because HgCl₂ forms complex ions readily with various salts, 2 it would appear that the assumptions made by Krönig and Paul would have to be carefully verified before broad generalizations can be drawn from the effects of NaCl upon HgCl_2.

Rideal and Rideal 3 attempt to explain the effects of salts upon germicides by the effects of these salts upon the partition coefficient of the toxic molecule between the bacterial cell and the medium. It is self evident that there are only 2 ways in which this germicidal efficiency of a solution can be increased.