SECTION TWO 



SUDAN 3 

 For staining fat in faeces 



Solution required: 



Sudan 3 saturated in equal 

 volumes of 70% alcohol and ether. 



Technique: 



1. A loopful of faeces is mixed with a drop of 50% alcohol. 



2. Add one or two drops sudan 3 solution ; then apply a cover- 

 glass before examining. 



Results: 



Neutral fat appears as highly refractile droplets or yellowish 

 flakes which stain orange to orange-red. 



Note: In normal faeces there is no appreciable amount of 

 neutral fat present. 



Fatty acids appear as flakes, which stain faintly; or as fine 

 needles which tend to collect in clusters and do not take the stain. 



Soaps appear as yellowish flakes, rounded or gnarled bodies, 

 everted like the pinna of the ear, or as coarse crystals, which do not 

 take the stain. 



On warming the preparation gently, fatty acids melt, whereas 

 the soaps do not. 



In the faeces of a healthy subject the only fat elements recog- 

 nizable under the microscope are yellow calcium or colourless 

 soaps. 



SUDAN RED 7B - TOLUIDINE BLUE 



A simple method for staining nuclei and lipids 

 simultaneously 



Solutions required: 



A. Sudan red 7B, saturated in iso- 



propyl alcohol (absolute) 



B. Toluidine blue, 0-5% in isopropyl 



alcohol (absolute) 



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