CHAPTER XXVI. 313 



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important part of the method, as sublimate and iodine both act detri- 

 mentally to staining. After washing in Na 2 S 2 3 , wash off in a stream 

 of aq. dest. ; roll the water off the slide with 1 or 2 drops of alcohol 

 (90 per cent.), wipe the slide dry around the sections, and pour on 

 3 to 4 drops of Ehrlich's acid haematoxylin to every section. Leave 

 exposed on bench ten minutes. Remove the hsematoxylin by 

 rolling it off with drops of alcohol (90 per cent.) from a drop-bottle ; 

 do not wash off the stain with water as this lowers the viscosity of 

 the solution and allows a diffuse staining. 



Wash away alcohol with a stream of aq. dest. till every trace of 

 stain is removed from the slide. 



Blue the hsematoxyiin lake and remove acid from combination 

 with the proteins of the section by dropping on the latter 8 to 10 

 drops (or more for a number of sections) of the following tap water 

 substitute :- 



KHC0 3 2grms. 



MgS0 4 7H 2 20 grms. 



Aq. dest. ...... 1000 c.c. 



Sat. with camphor, or thymol; 



After three to five minutes wash off the alkaline solution thoroughly 

 in aq. dest. Wipe around sections to remove superfluous water, 

 and add a 1 in 2000 solution of azoeosin (not eosin) or Biebrich 

 scarlet dissolved in this medium :- 



Glycerol . . . . . .2 per cent. 



Methyl or 96 per cent, ethyl alcohol .8 

 Dist. water . . . . . 90 



Use azoeosin (Bayer) for bichromated material and Biebrich scarlet 

 for non-bichromated material. Leave in the acid dye for ten to 

 thirty minutes, rinse off in aq. dest., rapidly dehydrate in 90 per cent, 

 and absolute alcohol ; xylol, and xylol balsam. 



In my hands weak watery solutions of good Eosin have not given such 

 satisfactory results. Scott believes that sulphonated monazo colours, 

 such as orange G and Bordeaux R, are useless. Eosin is much less 

 precise than Biebrich scarlet and azoeosin. The special points about 

 this method are : (1) Getting rid of all corrosive and iodine. (2) Stain- 

 ing by placing hsematoxylin on slide where the solution can evaporate, 

 and thus arrive at a state of viscosity which automatically prevents 

 overstaining. (3) Washing off stain in alcohol, not water, thus pre- 

 venting diffuseness. (4) A definitely alkaline tap-water substitute. 

 (5) A precise counter-stain. 



Histologists and cytqlogists carrying out work on chromophility are 

 recommended to use this method as a standard for either basophility or 

 oxyphility. Note, however, that granules which stain basophil by this 



