902 SUMMARY OF CURRENT RESEARCHES RELATING TO 



violet. The latter, therefore, entered into chemical union with the 

 pigment, the new body only showing a colour differing from that of 

 the dye. Thus, too, the rose- orange staining of red blood-corpuscles 

 by eosin may be regarded as the result of a chemical reaction. 



The author concludes by expressing the opinion that the staining 

 problem of the future will be solved by the aid of chemical reaction. 



Staining Methods.* — Dr. J, H. List discusses some double stains 

 which he has used for a long time with excellent effect, especially on 

 gland and epithelium. 



1. Bismarck-brown and methyl-green stain is prepared according 

 to Weigert's method, i. e. 5 grm. of pigment to 100 c.c. aq. destil. 

 The sections are left in the brown solution for from two to fifteen 

 minutes. They are then washed and removed to the green stain, 

 where they remain until they have assumed a dark-green colour. 

 They are again washed and placed in absolute alcohol. Experience 

 is the only guide as to when they should be taken out of alcohol, but 

 as soon as a sap-green hue appears the sections may be withdrawn 

 and placed in bergamot, xylol, &c., to clarify. The advantage of 

 this method is that Bismarck-brown gives with methyl-green a beauti- 

 fully distinct sap-green colour, while for goblet-cells and mucous 

 membrane it is especially valuable, because the intracellular network 

 is coloured brownish green or dark brown, and stands out with a 

 sharpness as in no other staining combination. 



2. Bismarck-brown and anilin-green may be used in an exactly 

 similar manner. 



3. Eosin and methyl-green were first used by Calberla, who dis- 

 solved a mixture of 1 part eosin and 60 parts methyl-green in 30 per 

 cent, warm alcohol. The author uses the stains separately. The 

 sections are first placed in an alcoholic solution of eosin made by 

 mixing 5 c.c. of a watery solution of eosin (0 • 5 grm. to 100 c.c. aq. 

 dest.) with about 15 c.c. absolute alcohol. Two to five minutes suffice 

 to stain deeply. Wash again and transfer to absolute alcohol, from 

 which it is usual to remove the sections when the eosin is perceptible. 

 They are then placed in the clarifying medium. This method of 

 staining may be recommended for epithelium, mucous membrane, and 

 cartilage. 



4. Eosin and anilin-green. Schiefferdecker was the first to employ 

 this method of double staining. The following modification may be 

 employed with excellent results for cartilage and glands. An alcoholic 

 solution of eosin is prepared as in No. 3. After remaining in this 

 solution for fifteen minutes or so, the sections are washed in alcohol, 

 and are then transferred to an alcoholic solution of anilin-green. 

 After remaining in this for fifteen minutes, they are removed to absolute 

 alcohol, where they remain until the eosin stain begins to show itself. 



5. Haematoxylin-glycerin and eosin. Eenaut's method f of double 

 staining, somewhat modified, produces splendid preparations. Three 

 or four drops of Eenaut's haematoxylin-glycerin are mixed with 1/4 



* Zeitschr. f. Wiss. Mikr., ii. (1885) pp. 145-50. 



t Oomptes Kendns, Ixxxviii. (1879) p. 1039. See this Journal, ii. (1879) 

 V. 763. 



