222 Ajncrican Quarterly Microscopical Journal. 



with it, however, and after many unsuccessful trials, I felt con- 

 vinced that, although the materials employed were of the 

 proper kind, the manner of using them was faulty. 



After Mr. Bullock, of Bullock & Crenshaw, prepared for me a 

 solution of sulphindigotate of soda, I again renewed my experi- 

 ments, and they were crowned with success. This solution I 

 use with uniform results, in connection with carmine, in the 

 following manner: — The sections are first stained with car- 

 mine, as described above, care being taken to wash all traces 

 of acid out of the tissues; they are then immersed in a solution 

 of 2 drops of sulphindigotate of soda solution in i ounce of 

 95^ alcohol, which should be filtered before using, and are 

 left therein from 6-i8 hours, according to the rapidity with 

 which the elements take up the indigo. When sufficiently 

 stained the sections are placed in strong alcohol, and are 

 ready for mounting. 



The sulphindigotate of soda solution is prepared, according 

 to the process devised by Mr. Bullock, by first digesting best 

 Bengal indigo with Nordhausen sulphuric acid. The excess of 

 acid is then removed by washing, the coloring matter precipi- 

 tated with chloride of sodium, and left standing for several 

 days. The precipitate is then separated from the mother 

 liquor by filtering through flannel, and the excess of chloride of 

 sodium washed out by pouring cold water through the filter 

 until the coloring matter begins to dissolve. The washing is- 

 then stopped and the precipitate dissolved in warm distilled 

 water to saturation, which makes a solution of a deep, greenish 

 blue color. 



The effect of this mode of staining is to leave the nuclei 

 bright red, while the formed material of the cell is slightly 

 tinged with blue. The connective tissue fibers become stained 

 with a deep blue color, while the blood vessels are purplish, and 

 mapped out with surprising distinctness. Epithelium and 

 hair take this staining in a very curious manner, inasmuch as 

 the cells of different ages take different colors, ranging from a 

 brilliant, emerald green, to purple, violet, and olive green, thus 

 affording a valuable means of differentiation, especially in 

 epitheliomas, where the so-called pearls are brought out with 

 great distinctness, being of a different color from the rest of 

 the cells. 



This process seems somewhat troublesome, especially if the 



