Note: The water must be heated to about 95° C. 

 in a large evaporating basin, the dyes and dextrin 

 added and stirred until dissolved. The resorcin is 

 then added and the solution raised to boiling point 

 with constant stirring. 



Procedure: 



1. When Solution B begins to boil, add 62 ml. of Solution A 

 slowly, in small portions at a time over a period of five minutes, 

 with constant stirring. 



2. Continue with the boiling and stirring for a further period of 

 two or three minutes until a coarse precipitate is obtained. 



3. After cooling filter by means of a Buchner funnel and flask 

 attached to a suction pump. 



4. Wash the precipitate with distilled water until the runnings 

 are colourless and the filtrate a clear azure blue; this usually 

 requires 8 to 10 litres distilled water. 



5. The preparation is then dried overnight in an incubator, 

 after removing the filter paper. 



Preparation of the staining solution : 



1. The dried elastin stain is now dissolved in 550 ml. absolute 

 alcohol plus I ml. HCl in a i -litre flask, the neck of which is 

 plugged lightly with cotton-wool. Solution is effected by boiling 

 gently for about thirty minutes on a water bath or electric hot- 

 plate. 



2. Cool; filter; add 19 ml. concentrated HCl; then shake well 

 and allow to stand for at least twenty-four hours. 



Staining technique: 



1. Sections are brought down to distilled water; then treated 

 with 0-5% aqueous potass, permanganate for five minutes. 



2. Rinse and bleach with 5% aqueous oxalic acid; then wash in 

 running water. 



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