72 OTHER ANILTN STAINS. 



ZSCHOKKE (Ibid., v, 4, 1888, p. 466) says that Benzopurpurin B 

 is the very best contrast stain to haematoxylin known to him. 

 It seems to him preferable to eosin on account of its not being 

 affected by alcohol or the usual clearing agents. Weak 

 aqueous solutions should be used for staining, which is effected 

 in a few minutes, and alcohol for washing out. Deltapurpurin, 

 a more purple red, has similar properties, and may be used in 

 the same way. The solution (aqueous) should be moderately 

 concentrated, and allowed to act for a minute or two. 



115. Biebricher Scharlach. (BIEBEICH SCAELET), a diffuse bright red 

 stain, may be useful as a contrast stain (see GRIESBACH, Arch.f. mik. Anat., 

 xxii, p. 132). 



116. Eosin, the potassium salt of a bromide of phthalein, is 

 found in commerce under the synonyms of Primerose Soluble, 

 Erythrosin, Pyrosin B., Rose B. a 1'Eau, The preparations 

 indicated by these names are not quite identical in their pro- 

 perties, but vary according to the different modes of manu- 

 facture. Most of them are soluble, both in alcohol and in 

 water, but some only in alcohol (" Primerose a 1 J Alcohol") 



Eosin was at one time much employed alone as a general 

 histological stain. Being convinced that this practice is now 

 entirely out of date, I suppress all the numerous formulae for 

 staining solutions which have been recommended from time to 

 time with great enthusiasm (see, however, FISCHER, Arch. f. 

 mik. Anat. xii, 1875, p. 349 ; LAVDOWSKY, Ibid, xiii, 1876, p. 

 359 ; ELOUI, Rech. Hist, sur le Tissu Conj. de la Cornee, Paris, 

 1881, and Zeit. f. wiss. Mik., i, 1884, p. 389) . It may be added 

 that experiments have not been made, or at all events have 

 not been published, in the direction of dissolving eosin in 

 anilin water (see footnote to 103), or combining its alcoholic 

 or aqueous solution with anilin or anilin-water which might 

 very possibly give results very different from those obtained 

 by the ordinary solutions. 



But eosin is of very great importance as a secondary or 

 contrast stain. It has already been mentioned that it washes 

 out many of the anilins that give nuclear stains by the indirect 

 method (see 98). Combined with a blue anilin, or with 

 haematoxylin, it gives instructive and durable double stains, 

 which are among the most beautiful that can be produced. 

 These will be treated of in the chapter on double-stains. 



