166 CHAPTER XTIT. 



of alum, heat and add 100 c.c. of the mixture. When the alum is dissolved 

 add 0'2 grm. of ferri-cyanide of potassium ; dissolve and add 3 grins, 

 more of alum and the rest of the mixture. Said to stain almost as well 

 as hseinaluni. Wash out with alcohol of 70 per cent. 



234 Other Alumina-Hsematein Solutions. A large number of 

 suppressed receipts will be found given in the earlier editions. 



265. R. HEIDENHAIN'S Chrome Haematoxylin (Arch. mile. Anat., 

 xxiv, 1884, p. 468, and xxvii, 1886, p. 383). Stain for twelve to twenty- 

 four hours in a \ per cent, solution of hseniatoxylin in distilled water. 

 Soak for the same time in a 0'5 per cent, solution of neutral chroruate 

 of potash. Wash out the excess of chromate with water. 



Objects that have been fixed in corrosive sublimate ought to be very 

 carefully washed out with iodine, or the like, as neutral hsematoxylin 

 forms a black precipitate with any excess of sublimate that may remain 

 in the tissues (see TORNIER, in Arch. mik. Anat., 1886, p. 181). 



The process is adapted io staining in bulk. You can decolour the 

 objects to any extent by prolonging the soaking in the chromate. 

 Bichromate will do instead of the neutral chromate. 



266 APATHY'S Modification of Heidenhaiii's Process (Zeit. wiss. 

 Mik., v, 1888, p. 47). This is an alcoholic method. Stain in a 1 per 

 cent, solution of hsematoxylin in 70 or 80 per cent, alcohol. Differentiate 

 sections of 10 to 15 ju, half the time of staining, sections of 25 to 40 fi 

 twice the time of staining, in 1 per cent, solution of bichromate of 

 potash in 70 to 80 per cent, alcohol, and wash out in alcohol of 70 per 

 cent. All these processes should be done in the dark. 



For celloidin series of sections, Apathy (ibid, 1889, p. 170) stains in 

 the hsematoxylin solution as above for ten minutes ; then removes the 

 excess of hsematoxylin fluid from the sections by means of blotting- 

 paper, and brings the series for five to ten minutes into 70 per cent, 

 alcohol containing only a few drops of a strong (5 per cent.) solution of 

 bichromate. 



267. SCHULTZE'S Chrome Haematoxylin (Zeit. iviss. Mik., xxi, 1904. 

 p. 5). The tissues to be fixed for twelve or more hours in a bichromate 

 or chromic acid solution, preferably an osmium -bichromate mixture or 

 liquid of Flemming. Then to be washed out for twenty four hours in 

 50 per cent, alcohol in the dark and stained for twenty-four hours or 

 more in 0'5 per cent, hsematoxylin in alcohol of 70 per cent., then 

 washed out in alcohol of 80 per cent. 



268. HANSEN'S Chrome Hsematoxylin (ibid., xxii, 1905, p. 64). 

 Ten grins, of chrome alum boiled in 250 c.c. of water till green, and 



( 1 grm. hsematoxylin (dissolved in 15 c.c. of water) added ; to the mixture 

 when cold add 5 c.c. of sulphuric acid of 10 per cent, and (drop by drop) 

 a solution of 0'55 grm. of bichromate of potash in 20 c.c. of water. 

 Filter before use. Wash out with water free from air. 



