STAINING, PRACTICAL AND THEORETICAL 



Notes: 



(a) The freshly prepared hexazonium sah (in sohition G) is 

 sufficiently stable at acid pH to permit incubation at room tem- 

 perature without change of the incubating medium for sixty 

 minutes. 



(b) The colour of the hexazonium compound is reddish at 

 acid pH, becoming brownish towards neutral. 



(c) This new diazonium compound, introduced by Davis and 

 Ornstein (1959), " hexazonium pararosaniline," was successfully 

 used in the demonstration of esterases at microscopic and electron 

 microscopic levels. 



(d) Besides the very good localization, the advantages of the 

 method described above are: a-naphthyl phosphate is water- 

 soluble; it is more readily hydrolysed than the phosphate esters 

 of naphthol AS or indoxyl derivatives ; the reagents are commer- 

 cially available; and the method works easily. 



(e) Readers are referred to the original paper for more detailed 

 information. 



Reference: Barka, T. (i960). 



HICKSON'S PURPLE 

 A general stain suitable for class work 



Solution required: 

 Hickson purple, saturated aqueous. 



Technique: 



1. Bring sections down to water as usual. 



2. Stain in Hickson's purple for ten to twenty minutes. 



3. Dehydrate, clear and mount. 



Results : 



Leucocytes, purple ; erythrocytes, distinct red. The rest of the 

 tissues purple. 



Reference: Cannon, H. G. (1941). 



246 



