180 CHAPTER XIV. 



an liour than tliat of gentian or dahlia is in a minute, so 

 that the process may be controlled under the microscope 

 if desired. For this reason I think this stain may be useful 

 to beginners, but I myself prefer gentian. It is a very 

 powerful stain. 



Tliionin is a specific stain for mucin, q. v. Some observers have found 

 the stain to fade. Wolff (Zeit. wiss. Mih., xv, 1899, p. 312) says that 

 to avoid this, preparations should be mounted in a little solid oolo- 

 phonium or balsam melted over a flame. Fblizat and Beanca {Journ. 

 Anut Phys., xsxiv, 1898, p. 590) mount without a cover. Henneguy 

 {in litt.) clears with acetone. 



King {Anat. Record, iv, 1910, p. 236) stains with a saturated solution 

 in carbolic acid of 1 per cent., and finds the stain permanent. 



Nicolle's " thionine pheniquee " consists of 1 part of saturated 

 solution in alcohol of 50 per cent., and 5 parts of 2 per cent, aqueous 

 solution of carbolic acid. 



289. Other Eegressive Stains. — The following may be 

 useful : — 



Dahlia, according to Flemming [Arch. milt. Anat., xix, 

 1881, p. 317), best used in aqueous solution, either neutral 

 or acidified with acetic acid, and differentiated with neutral 

 alcohol. A pure blue stain, which keeps well. See also 

 ScHDBEEQ, in Zeit. iciss. Zool., Ixxiv, 1903, p. 7, and Ixxxvii, 

 1907, p. 557. 



Victoria Blue (Victoriablau) (Lcstgaeten, Med. Jahrb. k. 

 Ges. d. Aerde zu Wien, 1886, pp. 285— 291).— This dye 

 ("Victoriablau 4 A") has a special affinity for elastic fibres. 

 For this object Lustgarten recommends an alcoholic solution 

 of the dye diluted with two to four parts of water. Fixation 

 in chrom-osmium, or at least in a chromic mixture, is, I 

 believe, a necessary condition to this reaction. And you must 

 stain for a long time. 



Victoria has also a special affinity for mucus-cells, from 

 which it is not washed out by alcohol, and for cartilage. 

 This stain keeps very well. 



With Toluidin Blue I have had some superb stains of chromatin, 

 unfortunately accompanied by a diffvise staining of cytoplasm. 



Mann {Zeit. wiss. Mile, xi, 1894, p. 489) states that he has had good 

 results by staining with it after eosin. 



See further as to the micro-chemical properties of this dye, Harris, 



