August 11, 1922] 



SCIENCE 



159 



There seem to be but two sources of crystal 

 violet in this country — namely, the du Pont 

 Company and the National Aniline Company. 

 The du Pont product we have tested and found 

 to be of very good quality. The National Ani- 

 line product was not obtained in time to include 

 in the cooperative tests, but upon examination 

 by the writer it appears to be entirely satis- 

 factory for the Gram stain. 



Crystal violet can be obtained from nearly all 

 the dealers in biological stains but we are 

 informed that nearly all of them buy the du 

 Pont product and rebottle it without any puri- 

 fication or standardization. The du Pont Com- 

 pany does not sell this dye in small bulk, so 

 when ordered for staining purposes it is well 

 to buy it through one of the dealers in stains 

 but to specify the product desired. The Na- 

 tional Aniline Company sells crystal violet both 

 in bulk as a dye and in small containers as a 

 stain. 



If gentian violet is ordered it is recommended 

 that it be purchased from one of the following 

 concerns, all of which have been tested for the 

 Gram stain and found to be very satisfactory: 

 Coleman and Bell, Goldin La;boratories, H. S. 

 Laboratories, National Aniline and Chemical 

 Company and Providence Chemical Company. 



In using any of these dyes it must be remem- 

 bered that owing to the presence of a large 

 amount of dextrin and possibly other impuri- 

 ties in the Griibler product the American stains 

 are two to four times as strong. This must be 

 allowed for in preparing the formulae. Those 

 formulae which call for a definite amount of 

 saturated alcoholic solution of gentian violet 

 do not need to be changed, but those calling for 

 a definite number of grams per 100 ee. must be 

 modified to suit these more concentrated 

 products. 



HEMATOXYLIN 



One source of American haematoxylin proves 

 to be very satisfactory for general purposes 

 and is specially recommended for cytological 

 work. This is the e.p. product prepared by 

 McAndrews and Forbes. It is handled by all 

 of the dealers in stains but generally without 

 indicating the manufacturer on the label. 

 Although this is probably the only c.p. haema- 

 toxylin on the market and is handled without 



modification by every concern that deals in 

 these products, nevertheless users of this stain 

 are recommended to specify the McAndrews and 

 Forbes product in order to discourage dealers 

 of these stains from omitting the manufac- 

 turer's name from the bottles when all they do 

 themselves is to rebottle the stains. The 

 McAndrews and Forbes haematoxylin has been 

 enthusiastically endorsed by practically every 

 one who has used it, generally with the state- 

 ment that it is better than some Griibler sam- 

 ples. 



EOSINE 



The situation in regard to eosine is not quite 

 so satisfactory, but even in this case it is not 

 discouraging. The Griibler samples of eosine 

 seem to have varied considerably, certain sam- 

 ples proving poorer than certain American 

 samples and others distinctly better. For the 

 present it can merely be said that the most 

 promising American samples so far tested have 

 been those from the Geigy Chemical Company 

 and from the Heller and Merz Company, among 

 the manufacturers, whUe among the dealers in 

 biological stains, apparently satisfactory sam- 

 ples have been obtained from D. H. Pond of 

 Cleveland, Ohio, from the Providence Chemical 

 Company and from Coleman and Bell. The 

 latter has been tested with good results in 

 Mallory and Wright's methylen-blue-eosine for- 

 mula. These samples have also been used in 

 counterstaining against haematoxylin in his- 

 tological work and for staining red blood cells, 

 and have proved distinctly better than the 

 Griibler samples submitted for comparison with 

 them but not as good as some Griibler samples 

 that the individual investigators have had on 

 hand in their laboratories. These results must 

 be regarded as very preliminary findings. 

 Further work is now in progress and it is 

 hoped in a later report to have more definite 

 information in regard to eosine. For the 

 present no definite recommendations are made. 

 It is suggested that where unsatisfactory re- 

 sults are obtained in counterstaining against 

 haematoxylin, Orange G may be substituted for 

 eosine to great advantage. 



ORANGE G 



Samples of Orange G have been tested from 

 Coleman and BeU, the du Pont, the Geigy 



