STAINING, PRACTICAL AND THEORETICAL 



Hydrochloric acid, pure, cone. 



(diluted 1 :3 with distilled 



water) . . . . . . . . 4 drops 



Note : All apparatus used must be scrupulously clean and 

 dry. 



{a) Add the sodium thiosulphate to the methylene blue solution 

 in a flask; shake to dissolve; then add the acid. 



{b) Heat carefully, agitating the solution, over a hunsen flame 

 for twenty to thirty minutes, until a light grey sediment is thrown 

 down. 



(c) Allow the solution to cool for ten minutes. 



(cf) Filter through two thicknesses of filter paper. 



(e) If the leuco base has been properly prepared it will be 

 colourless or slightly yellowish, otherwise it will be useless. 



(/) Should the filtered leuco base assume a blue colour it 

 should be left to stand for a while in the dark. 



{g) The leuco methylene blue solution should be prepared as 

 and when required for immediate use; it will, however, keep in 

 the dark for ten to twelve hours. 



B. Acid fuchsin, 0-05% aqueous 



Technique: 



1. Cut frozen sections, 10-15/^ in thickness, of fresh unfixed 

 fragments of tumour or other pathological material and transfer 

 to physiological saline solution. 



Note: Pieces of normal or pathological tissues may be kept 

 before use in physiological saline, in a refrigerator at — 2°C 

 to + 2° C for a period not exceeding two days, 



2. Transfer sections, by means of a pipette or a glass rod, to 

 slides. 



3. Draw off any excess saline solution from the slides with 

 filter paper. 



4. Spread sections over slides by means of needles, 



5. Allow to dry at room temperature. 



6. Besides the section of tumour or other pathological material, 

 a section of normal tissue should be attached to the slide to 

 serve as a control of the staining effects. 



Note: When both sections on the slide are dry they are ready 

 for staining immediately but they need not be stained for one or 

 two days thereafter. The authors state that dried sections of 

 malignant tumours preserve their typical staining capacity for 

 two weeks, provided they are kept in a dry, dark place. 



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