XXXI] SPINAL CORD 245 



Staining medullated fibres. The method given in the text 

 7 is the Heller-Kobertson modification of the Weigert-Pal 

 method ; it is on the whole the simplest and best. 



If the tissue has been hardened in Miiller's fluid or potassium 

 bichromate, the medullated fibres may be stained by one of the 

 methods given below. 



After hardening in formol, sections may be placed in chromic 

 acid '5 p.c. for half-a-day, for about an hour in 80 p.c. alcohol, 

 then stained by Weigert's hsematoxylin method. 



Welgert's method. The tissue is imbedded in celloidin, the block 

 placed for a day in the warm in a mixture of equal parts of cold 

 saturated acetate of copper and 10 p.c. aqueous solution of the double 

 tartrate of potassium and sodium ; 



and for a day in the warm in sat. neutral acetate of copper 

 solution diluted one half; 



it is rinsed in water, placed in 10 p.c. alcohol for \ hour, 

 and cut; 



the sections are placed for 4 to 24 hours in the hcematoxylin sol. 

 (below) ; 



differentiated in a few c.c. of a mixture of 2 grams borax ; 

 2*5 grams potassium ferricyanide, 100 c.c. water ; 



and thoroughly washed with water. 







Modification by Pal. Miiller's fluid is said to give better 

 results than potassium bichromate. 

 The following mixtures are required : 



Staining fluid Hsematoxylin 1 gram. 

 Absolute alcohol 10 c.c. 

 Lithium carbonate 1 gram. 

 Distilled water 90 c.c. 



The first two and the last two are perhaps best made separately 

 and mixed when required. 



Decolourizing fluid Oxalic acid 1 gram. 



Potassium sulphite 1 gram. 

 Distilled water 100 c.c. 



