H^MATOXYLIN AND EOSIN. 125 



few drops of acetic or picric acid, and then double-stain either with rosem 

 and anilin blue, or with anilin violet and anilin blue, or with anilin violet 

 and anilin green, or with rosein and anilin green. 



H. Gribbes says of these methods that their great utility consists in their 

 power of differentiating glandular structures according to their secretions. 

 In a section of a dog's tongue " the ordinary mucous glands will be found 

 to have taken on a purple colour, while the serous glands which supply the 

 secretions to the taste-organs stain a totally different colour." 



235. Picro-Carmine and Eosin (LANG, Journ. Roy. Mic. Soc., ii, 163 ; 

 Zool. Am., ii,p. 45 ; Mitth. d. Zool. Stat. zu Neapel, Bd. ii, p. 1, et seq.). 

 Take 50 parts 1 per cent, picro-carmine, 50 parts 2 per cent, eosin (aqueous 

 solution). The objects, previously hardened in alcohol, are left in the 

 mixture half to four days. Wash out the picrin by 70 per cent, alcohol, 

 which must be frequently changed, and be followed by 90 per cent, and 

 absolute alcohol until no more eosin is dissolved out. 



For Turbellaria. It has not been found useful for other objects. 



236. Carmine and the Metallic Stains. These combinations 

 have been sufficiently spoken of in the passages devoted to 

 gold and silver impregnation-methods. It will suffice here to 

 call renewed attention to ZOLTAN v. ROBOZ, alum-carmine and 

 osmic acid ( 150). 



Combinations having Hsematoxylin for a Primary Stain. 



237. Haematoxylin and Picric Acid. This combination has 

 been treated of above ( 225). 



238. Haematoxylin and Eosin. This is a well-known com- 

 bination, and one of the most instructive that have yet been 

 imagined. Objects may be stained with haematoxylin (either 

 in the mass or as sections), and the sections stained for a few 

 minutes in eosin. I think it is better to take the eosin weak, 

 though it has been recommended (STOHR, see Zeit. f. wiss. 

 Mik., i, 1884, p. 583) to take it saturated. Either aqueous or 

 alcoholic solutions of eosin may be used. 



This method is most particularly recommendable for embryo- 

 logical sections, as vitellus takes the eosin stain energetically, 

 and so stands out boldly from the other germinal layers in 

 which the blue of the haematoxylin dominates. 



LIST (Zeit. f. iviss. Mik., ii, 1885, p. 148) stains for twenty- 

 four hours in a solution of three or four drops of Renaut's 

 haematoxylic glycerin ( 183) in 250 c.c. of water, and then 



