MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



Asparagine 



This occurs widely in the plant kingdom, but is most readily 

 demonstrated in etiolated seedlings of Lupins and tubers of 



Dahlia 



Solution required: 



Cupric acetate 5% aqueous. 

 Technique: 



1. Place strictly fresh sections in a drop of the cupric acetate on 

 a slide and leave therein for ten to twenty minutes. 



2. Add absolute alcohol slowly, a drop at a time, whilst examin- 

 ing under the microscope, until ultramarine spaerocrystals of 

 copper asparagine become visible, indicating the presence of 

 asparagine in the tissue. 



Calcium 



Solution required: 

 Oxalic acid 2% aqueous. 



Technique: 



1. Sections are placed directly onto a slide and flooded with the 

 oxalic acid solution and left for half an hour exposed to the air. 



2. Pour off some of the liquid ; then add a coverslip. 



3. Pipette a drop of absolute alcohol along one edge of the 

 coverslip, so that the alcohol is drawn under the coverslip by 

 capillary attraction. Examine under the microscope. 



Results: 



Calcium, if present, will be indicated by the small but easily 

 visible crystals of calcium oxalate. 



Calcium Oxalate 



Solutions required: 



A. Cupric acetate, saturated, aqueous. 



B. Ferric sulphate . . . . • • 5 gn^« 

 Acetic acid 20% aqueous . . 100 ml. 



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