THE MICROSCOPE. 225 



. jijeljeciiiros. 



On Fixing the Aniline Dves. — The British Medical Journal 

 for March 10 contains an article by Mr. H. A. Reeves, F. R. C. S. E., 

 on fixing the aniline dyes in microscopical staining; and though in 

 the article mention is only made of anatomical and pathological pre- 

 parations, we think it. 'likely that the method described will be found 

 capable of a much wider application. Mr. Reeves states, that for 

 the last eighteen months he has been systematically experimenting 

 with a vast number of chemicals, singly, and combined in various 

 proportions, with a view to finding a suitable mordant, and the result 

 has satisfied him that the dyes may be fixed by placing the stained 

 sections first, for from three to five minutes in a mixture of equal 

 parts of a saturated aqueous solution of tannin, to which a little car-, 

 bolic acid has been added, and distilled water. Then wash in water, 

 and transfer for the same length of time to a mixture of tartar emetic 

 and water, a few drops of a saturated solution of tartar emetic being 

 added to a watch-glass full of water. The sections should then be 

 again washed; placed for five or ten minutes in strong methylated 

 spirit, drained of superfluous spirit, and mounted in Canada balsam 

 or dammar, after having been passed through oil of cajuput, cloves, 

 juniper, aniseed, or turpentine. The tannin and antimony solutions 

 should be filtered into the watch-glass before using, as also the dyes. 

 Preparations hardened in Midler's fluid or spirit answer best, but 

 chromic acid hardened specimens can be used, if, previously to 

 staining, they be soaked for twenty or thirty minutes in methylated 

 spirit. 



Other agents will partially or completely fix some of the ani- 

 lines; such as arsenious, acetic, hydrochloric 'and carbolic acids, 

 hypophosphite of soda, tannate of soda, and silicate of soda, to which 

 a little hydrochloric acid has been added, and these should be tried 

 in special cases. A saturated aqueous solution of acetate of potash 

 fixes roseine, saffranine, and soluble blue, and partly fixes fuchsin. 



Mr. Reeves also draws attention to two or three new or little- 

 known dyes, which he thinks might be used with advantage in micros- 

 copy. The new dyes are phloxine and erythrosine. They stain 

 rapidly and deeply in weak aqueous solutions, and stand spirit well. 

 Connective substances and the protoplasm of cells are, in rapid 

 staining, preferred by them to the nuclei, which, however, stand out 



