18 Biological Stains 



tion must be given here to the situation which existed in the United 

 States and Canada, following the First World War, as it was this 

 which led to the establishment of the Biological Stain Commission, 

 the sponsor of this book. 



MODERN STANDARDIZATION OF STAINS 



The Biological Stain Commission is concerned with the inspec- 

 tion and standardization of stains, not with their manufacture, as is 

 sometimes supposed. It was learned in 1920, while the post-war 

 embargo on dyes was still in effect, that American scientists were 

 being supplied with dyes from three or four different stain com- 

 panies and that their products were not sufficiently uniform to be 

 reliable. Accordingly, through the cooperation of the National 

 Research Council of the United States and three or four American 

 scientific societies, the Commission on Standardization of Biological 

 Stains (now known as the Biological Stain Commission) was estab- 

 lished. The Commission is now an independent non-profit cor- 

 poration, having representatives on its membership of eight 

 American scientific societies with which it cooperates. The work 

 of the Commission is two-fold. First, by cooperation of various 

 biologists and chemists it gathers information concerning the 

 nature of dyes as related to their use in microscopic technic; sec- 

 ondly, by working with the manufacturers and dealers it en- 

 deavors to see that the supply of stains available in America is of 

 the highest possible quality as judged by their performance in 

 actual laboratory use. The first of these purposes has inspired 

 this book, which is now in its sixth edition, and at the same time 

 has led to the publication by the Commission of a journal. Stain 

 Technology and a loose-leaf manual, Staining Procedures 

 (Conn and Darrow, 1943-4). The second object is being brought 

 about by the plan of certifying stains. 



The certification plan has been adopted because of the great 

 difficulty of drawing up any chemical or physical standards to 

 determine which stains are satisfactory and which are not. If 

 such standards could be formulated, it would be possible to draw 

 up specifications with which manufacturers of stains would be 

 expected to comply. 



Specifications. Drawing up specifications for biological stains 

 has proved difficult. In many cases their chemistry is not en- 

 tirely understood, and even when it is, their behavior in actual use 

 is often dependent upon the amount and nature of impurities that 

 may be present in only minute quantities. Since these im- 

 purities are sometimes beneficial and sometimes detrimental and 

 their nature is often unknown, practical specifications are much 

 more difficult to draw up than in the case of ordinary chemicals 

 where a high degree of purity can be obtained and any impurity is 

 undesirable. 



