STAINING METHODS iV46-5 



STAINING FORMULAE 



There has always been a surprising amount of inaccuracy in the 

 hteraturc concerning staining sohitions. This is due to a variety 

 of causes: indefiniteness in the original j)ublication; mistakes of 

 copying by later authors; modifications of the original which are 

 not described as modifications and come later to be ascribed to the 

 original author; failure of authors to cite references when giving 

 their methods. For such reasons it has proved necessary in this 

 publication to give in many instances both the original (rather 

 indefinite) formula and an emended formula as interpreted by the 

 Committee. The Committee, however, assumes no responsibility 

 for the identity of the tivo, and offers the emendation merely to prevent 

 the perpetuation of formulae which are clearly ambiguous or indefinite 

 as to their ingredients. Recent cooperation between this Commit- 

 tee, the Biological Stain Commission, and the National Formulary 

 Committee of the American Pharmaceutical Association, has re- 

 sulted in the virtual adoption of these emended formulae. 



In the present edition of this leaflet the practice is still continued 

 of giving both the original and the emended formulae in such in- 

 stances. It is anticipated, however, that the latter will be regarded 

 as sufficiently standard, in a few years, so that the original formulae 

 can be dropped in future editions. 



In early editions of this leaflet staining formulae and methods 

 were merely taken from the literature without any endorsement 

 by the Committee. At present, greater experience in such matters 

 permits the Committee to recommend certain of the procedures, 

 and they are now grouped according to whether or not they are thus 

 endorsed. Several of the less frequently used methods formerly 

 given are now omitted. One or two new methods are included 

 among those recommended by the Committee. 



Staining Schedule. Tap vs. distilled water. When washing 

 slides after applying any stain, tap water is ordinarily more con- 

 venient to use than distilled water; and in the staining schedules 

 that follow, tap water is specified in those instances where its use 

 is considered to be ordinarily unobjectionable. It must be remem- 

 bered, however, that the use of distilled water is never contraindicated 

 for such purposes; and many bacteriologists prefer it for all steps 

 where washing is called for, because it is not subject to variation 

 in composition, buffer content, etc. 



General Bacterial Stains — Recommended Procedures 

 ziehl's carbol-fuchsin 



OLD STATEMENT OF FORMULA EMENDED STATEMENT OF FORMULA 



Solution A 



Sat. ale. sol. basic fuchsin 10 ml. Basic fuchsin (90% dye content)^ 0.3 g. 



5% sol. carbolic acid 100 ml. Ethyl alcohol (95%) 10 ml 



Solution B 



Phenol 5 g. 



Distilled water 95 ml. 



Mix Solutions A and B. 



^It is not necessary that dry stains of the exact dye content specified be used in this 

 or in the following formulae. Samples of higher or lower dye content may be employed 

 by making the proper adjustment in the quantity used. 



