42 ri i APT KR iv. 



3 Auf., 1896, p. 22] fix in the dark.) If yon ivish to have 

 a good stain with carmine you should not put the objects into 

 alcohol at all, even for a second, until they have been stained. 

 You may stain either with carmine or lisematoxylin, as 

 well as with tar colours. 



Bichromate objects have an ugly yellow colour which cannot be re- 

 moved by mere soaking in water. It is said that it can be removed by 

 washing for a few minutes in a 1 per cent, solution of chloral hydrate. 



Prof. GILSON writes me that alcoholic solution of sulphurous anhy- 

 dride (S0 2 ) is veiy convenient for the rapid decoloration of bichromate 

 objects. A few drops suffice. See also 37, and " Bleaching." 



To facilitate staining with hsematoxylin, WOLFF (Zeit. iviss. Mile., xv, 

 3, 1899, p. 311) first stains in Boehmer's hsematoxylin for twenty-four 

 hours, and then for a few minutes in the same hsematoxylin to which 

 has been added 1 drop per watch-glassful of 5 per cent, solution of 

 oxalic acid. 



The simple aqueous solution of bichromate is hardly to be 

 recommended as a fixing agent, because not only does it not 

 preserve nuclei properly, but also because it penetrates very 

 slowly. The first of these defects may be overcome entirely, 

 the second to some extent by addition of acetic acid ; whence 

 the liquid of TELLYESNICZKY, next . 



52. Acetic Bichromate (TELLYESNICZKY, Arch. mik. Anat., lii, 

 1889, p. 242) 



Bichromate ..... 3 grms. 



Glacial acetic acid . . . . 5 c.c. 



Water 100 



Smaller objects to remain in the fluid for one or two dnys, 

 larger ones longer. Wash well in plent}' of water, and pass 

 through alcohols of increasing strength, beginning with 15 

 per cent. 



Mixtures of bichromate with osmic acid have been given above, 43 

 and 44. 



53. MULLER'S Solution. 



Bichromate of potash . . . 2-2 J parts. 



Sulphate of soda .... 1 part. 



Water 100 parts. 



The duration of the reaction is about the same as with 

 the simple solution of chromic salt. 



