130 Biological Stains 



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being distinctly better than that of former years. When a stain 

 company submits a sample showing too blue or too yellow staining, 

 the fault is called to the manufacturer's attention, and they try to 

 submit another sample without that fault or with the opposite 

 fault. This often means the submission of two batches, one too 

 blue in its staining properties, the other too yellow; then it is a 

 fairly simple matter to determine the proper mixture of the two to 

 give best results. This has to be determined by actual staining 

 tests, not by means of any colorimeter or spectrophotometer. 



These observations undoubtedly explain the directions given by 

 Chamberlain* to mix equal parts of alcohol soluble safranin and 

 water soluble safranin for use in the Flemming triple stain. There 

 is no such thing as a safranin insoluble in either alcohol or water; 

 and the products formerly sold by Grubler as "wasserloslich" and 

 "spritloslich" respectively have been found to be identical so far 

 as chemical and optical analysis show. Probably, however, the 

 particular batches formerly employed by Chamberlain were 

 neither of them the correct shade in staining properties, while a 



*In early editions of his Methods in Plant Histology. 



