AF 11.1-12.1 



ACCESSORY FIXATIVE FORMULAS 



255 



made and, in this case, even more of the 

 cytoplasm can be dissolved by washing in 

 weakly alkahne solutions. Lithium car- 

 bonate solutions are often suggested, 

 though they are no more effective than 

 sodium carbonate solutions of the same 

 molar concentration. The three special 

 formulas given below (AF 11.1) for the 

 removal of picric from material have 

 specific functions indicated under each. 



The removal of fixatives which contain 

 mercuric chloride is a far more difficult 

 and \atal matter. It has long been known 

 that sections or wholemounts prepared 

 from mercuric-fixed materials tend to de- 

 velop needlehke crystals, or black gran- 

 ules, presumably of mercuric chloride. 

 The formation of these crystals cannot 

 always be prevented, even by prolonged 

 washing in water or alcohol, and it has 

 become customary to treat sections with a 



solution of iodine in potassium iodide, on 

 the ground that the mercuric iodide so 

 formed will itself form a complex with the 

 excess potassium iodide and thus be re- 

 moved. The exact composition of the 

 solution employed is not a matter of any 

 great importance, and the several for- 

 mulas given! below (AF 12.1) may be 

 diluted or increased in strength at the 

 option of the worker. The last division of 

 fixative removers (AF 13) gives two 

 formulas for the prevention of precipi- 

 tates, which occasionally occur in mate- 

 rials which have been fixed and stored in 

 formaldehyde for a long period. One 

 formula, which might more properly be- 

 long in the divisions on bleaches (AF 30), 

 is used to remove the black material depos- 

 ited by osmic acid on the outside of small 

 specimens. 



AF 11 FOR USE AFTER PICRIC MIXTURES 



AF 11.1 Formulas 



11.1 Bolcek 1930 23632, 47:334 



formula: abs. ale. 80, nitric acid 10, origanum oil 20, cedarwood oil 10 

 RECOMMENDED FOR: treatment of picric-fixed materials before celloidin embedding. 



11.1 Cappell test. Carleton and Leach 1938 Carleton and Leach 1938, 31 



reagents required: A.' 70% ale; B. 5% sodium thiosulfate 

 method: alternate sections between A and B 

 recommended for: removal of yellow color from mounted sections before staining. 



11.1 Lenoir 1930 6630, 103:1253 



formula: water 70, 95% ale. 30, ammonium acetate 10 



recommended for: removal of yellow color from picric-fixed specimens before embed- 

 ding or making wholemounts. 



AF 12 FOR USE AFTER MERCURIC MIXTURES 



AF 12.1 Formulas 



12.1 Gram 1884 Gram' s iodine — compl. script. 8645,2:6 



formula: water 5, iodine 1, potassium iodide 2, water to 300 



12.1 Haug 1889 23632,8:11 



formula: water 50, glycerol 50, ADS 12.2 Lugol (1905) 2, potassium iodide 1 

 recommended for: removal of mercury fixatives. 



12.1 La Cour 1931 11360, 51:123 



formula: 80% ale. 100, potassium iodide 1, iodine 1 

 recommended for: removal of mercuric chloride fixatives. 



12.1 Lugol (1905) test. 1905 Lee Lugol's iodine — compl. script. 



Lee 1905, 62 

 formula: water 110, iodine 6, potassium iodide 4 

 preparation: Dissolve iodine and potassium iodide in 10 water. Dilute to 100. 



