50 SPECIFIC METHODS. 



3 drops to every 10 cc. of the Hsematoxylin solution. This is 

 practically Weigert's Hsematoxylin. 



In this stain the sections are allowed to remain from 5 to 

 6 hours until they are opaque, and have a dark bluish-black 

 colour. 



They are then removed to Distilled Water and thoroughly 

 washed till no more colour comes away. If the sections are 

 not sufficiently stained a little Carbonate of Lithium solution 

 is added to the "Water. 



The sections are now placed in 0'25 aqueous solution of 

 Permanganate of Potassium from 15 to 20 seconds to diffe- 

 rentiate ; they are then placed in 



Pal's Solution. Oxalic Acid, 1 grm. ; Potasrium Sulphite, 

 1 grm. ; Distilled Water, 200 cc. ; and allowed to remain till 

 the white and grey matters are distinctly defined. This takes 

 from 1 to 2 minutes ; should black spots appear, the sections 

 must be replaced in the Permanganate of Potassium solution, 

 and put back into Pal's solution ; they are then washed for 

 15 minutes in Water. 



By this means the medullary sheaths are stained a bluish- 

 black colour, while the rest of the tissue remains unstained. 



The nuclei may now be stained in Alum Carmine. 



Finally dehydrate, clear, and mount. 



FAL-EXNER METHOD. 



This is the most rapid of all, and takes about 3 days both 

 to harden and mount. 



The spinal cord or brain is cut into J-in. cubes and immersed 

 in ten times its bulk of \ p.c. solution of Osmic Acid for 2 

 days, the solution being changed each day ; the pieces are 

 then washed in Water, transferred to Absolute Alcohol, and 

 embedded in Celloidin or Paraffin. 



As the sections are cut they are placed in Glycerine, then 



