STAINS AND STAINING 61 



tory, especially for fungi to be mounted whole. With the rapid im- 

 provement in the manufacture of stains, it is very probable that other 

 dealers will have equally good products. Investigators will save time 

 and money by keeping track of the findings of the commission on 

 Standardization of Biological Stains. 



Haematoxylin and eosin and methyl blue and eosin are good com- 

 binations. The eosin should follow the other stain. 



Erythrosin. — This is really an eosin, but there is some difference in 

 the method of manufacturing. It is more precise and a more transpa- 

 rent stain than eosin and is to be preferred for nearly all staining of 

 paraffin sections. IMake a 1 per cent solution in distilled water or in 70 

 per cent alcohol. It gives good results when made up according to the 

 general formula. 



Erythrosin stains rapidly, from 30 seconds to 3 minutes being suffi- 

 cient. When used in combination with other stains, erythrosin should 

 come last. 



Magdala red.— The name, Magdala red, is too indefinite to mean 

 anything. The Magdala red echt (genuine) , of Griibler, is worth nothing 

 as botanical stain. Sometimes a bottle labeled simply Magdala red 

 gave fine results. It would seem that the occasional stains which suc- 

 ceeded are practically the same as the American stain, phloxine; at 

 least, a stain called Phloxine B (color index number 778), made by the 

 National Anilin and Chemical Company, behaves like the best "Mag- 

 dala red" and seems to give uniform results. 



Phloxine B.— Probably the occasional lots of Magdala red which 

 proved to be so satisfactory in the Magdala red and anilin blue com- 

 bination were phloxine. 



Phloxine 1 g- 



Ninety per cent alcohol 100 c.c. 



This stain is particularly valuable for staining algae which are to be 

 mounted whole. In this case it should be followed by anilin blue. Full 

 directions are given in chapter viii. 



For staining sections to be mounted in balsam, dilute the phloxine 

 one half with water. Stain for 24 hours, dehydrate in 95 and 100 per 

 cent alcohol, clear in clove oil, transfer to xylol, and mount in balsam. 



Phloxine stains lignified, suberized, and cutinized structures, and 

 also chromosomes, centrosomes, nucleoli, and pyrenoids. It is likely 

 to overstain, but the differentiation is easily secured by placing the 



