S Ian da rd izatiou of Stains 113 



the stamp of the commission on them. Specifications of the most impoi- 

 tant dyes now have been drawn up by the commission putting these dyes 

 on a certification basis. The specifications are partly chemical and partly 

 spectrophotometric and contain detailed statements as to how the dyes 

 should be tested for their behavior with the results to be expected from 

 their tests. Batches of dyes approved by the commission bear a special 

 label furnished by the commission and known as a certification label. 

 On it is a C.I. number (Colour Index number) indicating the certifica- 

 tion number of that particular batch. This number means that (1) a 

 sample of that batch was submitted to the commission for testing and a 

 portion of it is on file; (2) the sample pro^ed true to type by spectro- 

 photometric tests; (3) its dye content met specifications and is correctly 

 indicated on the label; (4) it was tested by experts in the procedure 

 named on the label and foinid satisfactory; and (5) no other batch can 

 be sold under the same certification number. Any description of the 

 use of the stain should be followed by its C.I. ninnber or a C.C. indi- 

 cating that it is Commission Certified.^ 



Unless otherwise specified, dyes can be purchased from most of the 

 scientific supply houses with chemical outlets: Coleman and Bell Co., 

 Hartman-Leddon Co., Fisher Scientific Co., Allied Chemical Corpora- 

 tion {National Aniline Division), and others. 



Sources of foreign stains: 



G. Grilbler and Company, West Berlin, Germany. 



Esbe Laboratory Supplies, -/^P Bloor St. W., Toronto, Canada, outlet 



for Giirr Stains (Alichrome Stains). 

 Edward Gurr, London, England. 



Pfatz and Bauer, Inc., Empire State Building, New York City. 

 Roboz Surgical Company, Washington, D.C. 



References: Baker (1945, 1958); Cole (1933, 1943); Conn (1946, 1948, 

 1953); Holmes (1929); Singer (1952); and Stearn and Stearn (1929, 

 1930). 



^C.I. numbers used in this text arc from the new revised list. 



