PLASMA STAINS 169 



It can in some cases be employed by dissolving it in the solution of 

 anotlier dye (see Picro-carmine, Legal's alum-carmine, § 256, etc.) ; or 

 (for sections) by dissolving it in the xylol or chloroform used for clearing. 



Though picric acid is a useful ground stain, it is at most a rough one, 

 being very diffuse. It stains, however, horn, chitin, muscle and 

 erythrocytes, with special energy. 



According to Froulich {Zeit. iviss. Mik., xxvii, 1910, p. 349) picra- 

 minic acid (from Griibler & Hollborn) has some advantages over picric 

 acid. 



326. Van Gibson's Picro-Saurefuchsin (from Zeit. wiss. Mik., 

 xiii, 1896, p. 344). To a saturated aqueous solution of picric 

 acid are added a few drops of saturated aqueous solution of 

 Saurefuchsin, until the mixture has become garnet-red. Or 

 {Trans. Amer. Micr. Soc, xix, 1898, p. 105) to 100 parts of the 

 picric acid solution add 5 parts of 1 per cent, solution of Saure- 

 fuchsin. After staining (section only), rinse with water, 

 dehydrate, and clear in oil of origanum. 



Ohlmacher (Journ. Exper. Med., ii, 1897, p. 675) adds 0-5 per cent, 

 of Saurefuchsin to a saturated solution of picric acid which has been 

 diluted with an equal quantity of water. He uses this after previous 

 staining with gentian violet. 



Ramon y Cajal recommends 0-1 grm., of Saurefuchsin to 100 of 

 saturated solution of picric acid (Schaffer, Zeit. wiss. Zool., Ixvi, 

 1899, p. 236). 



Hansen (Anat. Anz., xv, 1898, p. 152) adds 5 c.c. of 2 per cent, 

 solution of Saurefuchsin to 100 c.c. saturated solution of picric acid, 

 and for staining adds to 3 c.c. of the mixture one-third of a drop of 

 2 per cent, acetic acid, stains for a few minutes or hours, rinses in 3 c.c. 

 of water with 2 drops of the acidified stain added, dehydrates clears 

 with xylol, and mounts in xylol-balsam . Connective-tissue red, elastin 

 and all other elements yellow. 



Weigert (Zeit. wiss. Mik., 1904, p. 3) adds 10 parts of 1 per cent. 

 Saurefuchsin to 100 of saturated picric acid. 



See also Moller, op. cit., xv, 1898, p. 172. 



This stain is generally used as a contrast stain to follow ha;matoxylin. 

 Apathy {Behrens'' Tabellen, 3rd ed., p. 129) takes for this purpose 1 grm. 

 of Saurefuchsin in 500 c.c. of saturated solution of picrate of ammonia. 



WiLHELMi (Fauna Flora Golf. Neapel, xxii, 1909, p. 18) takes 0-2 grm. 

 Saurefuchsin, 0-8 grm. picrate of ammonia, 10 grm. absolute alcohol, 

 and 89 grm. water. 



E. and T. Savini (Zeit. wiss. Mik., xxvi, 1909, p. 31) use a formula 

 due to Benda. Ninety-five volumes of saturated solution of picrate of 

 ammonia are mixed with 5 volimies of 1 per cent, solution of Saure- 

 fuchsin. For use, two to four drops of saturated solution of picric acid 

 are added to 10 c.c. of the mixture. This neither overstains nor attacks 

 the primary stain. 



327. Flemming's Orange Method* (Arch. mik. Anat., xxxvii, 1891, 

 pp. 249 and 685). Stain sections of Flemming or Hermann material in 

 strong alcoholic safranin solution diluted with anilin water (§ 372) ; 

 differentiate in absolute alcohol, containing at most 01 per cent, of 

 hydrochloric acid, until hardly any more colour comes away ; stain for 

 one to three hours in gentian violet (§ 373) ; wash for a short time in 

 distilled water ; treat with concentrated, or at least fairly strong, 



* Refer also to § 814. 



