Colored Flocculation Reactions.∗

Abstract

Summary

A method is suggested for all fiocculation reactions, especially for the Hecht-Müller Ballung Reaction of elective staining of the extract colloid which brings about a distinctive color effect that facilitates the reading of results without impairing their specificity. Readings are best made against a white background (white paper). Positively reacting sera show a bright red ball, and after it is formed the chosen counterstain, blue, violet, or green appears in the surrounding fluid. Negative sera show a turbid light violet to greenish-blue color, permitting an immediate differentiation.

All flocculation reactions are based upon colloidal chemical processes. What is more natural than to introduce into these reactions dye colloids for the purpose of making the flocculation more distinct, firstly by coloring the flocculi and secondly by making them more voluminous by the joining of the dye colloids in the flocculation of the extract.

Experiments of this kind have been made frequently, but have been only partially successful.

Experiments were reported¹ in which the extract colloid could be colored, whereas a contrast coloration was hardly possible of attainment. These experiments were carried out on the Hecht Flocculation Reaction (H. F. R.), on the Sachs-Georgi-Reaction (S. G. R.), and the typhoid reaction, using the Flicker Diagnostikum.

The experiments since then, carried out with well over 100 of the most diversified dyes, led to a provisional result as follows:

The goal of these studies was the development of a flocculation reaction in which a part of the coloring matter would join with the flocculated extract so that in the case of a positive reaction the fluid remaining after the flocculation of the extract would be colored differently than the fluid in a negative reaction (with the extract not flocculated).

Experiments of this sort were done particularly with the Hecht-Muller-Ballung reaction but show in their results that they may be employed in all flocculation reactions for syphilis which are done with alcoholic extracts without addition of Balsam (Sachs-Georgi-Reaction, Kahn Reaction, Kline Reaction, Hinton Reaction, etc.).

The principle of the staining consists in the following: 1. The extract is electively stained by a dye which does not leave any color in the fluid remaining after the precipitation of the extract colloid. 2. As counterstain of the salt solution (the extract-free fluid), dyes must be used which leave the extract colloid unstained or which color it but slightly. Among numerous lipoid stains, the only one of value was Sudan 3 of the I. G. Farbenindustrie.