HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Sanderson, E. S. Articles by Yoe, J. H. Search for Related Content PubMed Articles by Sanderson, E. S. Articles by Yoe, J. H.

Observations on the Proposed Gold Chloride Titration for Determining the Toxicity of Diphtheria Toxin

From the Department of Bacteriology and Pathology, and the Cobb Chemical Laboratory, University of Virginia, Charlottesville, Virginia

Abstract

The results of the foregoing experiments may be summarized as follows:

1. Six different diphtheria toxins when tested by the "gold chloride" and guinea pig methods failed to show any parallelism as to toxicity.

2. The green color zone produced in mixtures of gold chloride and toxic broths is not specific for toxin:

(a) Inactivated (heated) and non-inactivated toxins gave almost identical gold chloride titration figures.

(b) The amount of gold chloride necessary to bring about the maximum green coloration with toxic broths can be entirely altered by changing the initial hydrogen ion concentration and the buffer capacity of the broths.

(c) Several batches of uninoculated 1 per cent dextrose extract broth gave a green color zone when mixed with gold chloride.

3. Maximum green color in mixtures of broths and gold chloride is obtained at an approximate pH of 4.5.

4. The gold chloride test does not appear to be a satisfactory method for standardizing bacterial toxins in its present form.