Relationship of Sera and Spinal Fluids to Agglutination and Flocculation by Dyes.

Abstract

It has been known for a long time 1 that human red blood cells and bacteria could be agglutinated by solution of basic dyes. In addition M. Gutman 2 showed that whole serum could be flocculated by the same dyes. In our experiments we found that these phenomena were much more complex.

The human red blood cells used in the experiments were washed 3 times in normal saline (0.85%) in order to free them from all traces of serum. A 2% suspension of red blood cells was used. Whenever human serum was used in conjunction with the red blood cells the same types were employed in order to avoid agglutination of the cells by the serum. The standard dye used was a gentian violet solution 1:2500 in normal saline. The ingredients were mixed in equal amounts in narrow glass tubes by thorough shaking. Agglutination and flocculation could easily be observed macroscopically. For microscopic examination drops of the same ingredients were placed on glass slides and mixed with glass rods.

Results. 1. Flocculation of human sera: The flocculation of whole human serum by basic dyes noted by Gutman takes place only if relatively strong solutions are added. (e. g., 1/2-1% aqueous solutions of safranin or gentian violet). But by using weaker solutions different results were obtained. Whole human serum, or serum diluted with normal saline (0.85%) up to 1:6 is not flocculated by our standard solution of gentian violet. Flocculation here first occurs with a serum diluted 1:8 and increases in strength with higher dilutions of sera. In dilutions of serum of 1:64 flocculation decreases, and it does not occur when the serum is diluted beyond 1:128.

2. Agglutination of human red blood cells and bacteria. In accordance with the work of Gutman and others we found that solutions of basic dyes agglutinate red blood cells and bacteria.