MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



Sulphates 



Solutions required: 



A. Benzidine hydrochloride. . 

 Hydrochloric acid, cone. 



Distilled water 



B. Hydrochloric acid, cone. 

 Distilled water 



I gm. 

 3 ml. 

 97 ml. 



10 ml. 

 90 ml. 



C. Barium chloride 10%. 



Technique {a): 



Sections of fresh tissue are placed in a few drops of the benzi- 

 dine solution on a slide and examined under the microscope. 



Results: 



Scales or small glistening needles (benzidine sulphate) indicate 

 the presence of sulphates. 



Technique (b): 



For cereal seeds and other tissues which contain fat. 



1. Immerse the material overnight in acetone in a stoppered jar 

 or well-corked tube, to remove the fat. 



2. Transfer to slides; wash in two changes of pure acetone; 

 then allow the sections to dry on the slides. 



3. Add one drop each of Solutions B and C (above) to the slide 

 and examine under the microscope, under a high-power objective. 



Results: 



A granular precipitate (barium sulphate) indicates the presence \ 

 of sulphates. 



Tyrosine 



Solutions required: 



Sodium molybdate 1% in sul- 

 phuric acid, cone. 



Technique: 



1. Place sections on slide and cover with absolute alcohol. 



2. Allow the alcohol to evaporate completely. 



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