Biological stains are used to increase visual contrast between tissue elements. Slight differences in structure, dye content and impurities of the dye can result in serious trouble for the biologist or histotechnologist. These problems were first noticed by the earliest users of dyes in histology and still continue.
The first attempt at quality assurance in biological dyes was the result of advice given to a graduate student by Dr Weigert in 1880. The graduate student was Georg Grubler, who soon after completing his studies began supplying biological dyes which gave reasonably consistent results. The Grubler label came to be accepted as an adequate quality assurance, and the Grubler dyes achieved virtually a world-wide monopoly.
During World War I there was a complete blockade of Germany. As a result a domestic USA dye industry was initiated. This early industry had much to learn, and its products were at first not only poor textile dyes, but were often impossible as biological stains. After the USA entered the war, and as the armed services expanded, many laboratories had to be developed; and the dye quality situation became even worse. Particular problems focussed on the basic fuchsin and gentian violets important to bacteriologists; and the eosin, hematoxylin, methylene blue and phloxine used by histologists. However, there were actually few dyes which did not give problems.