A crystal of thymol should be added to the stock 

 bottle. 



Technique: 



1. Sections are mounted on slides and the paraffin wax removed 

 with xylol. If there is any doubt as to the nature of the fixative 

 which has been used, examine a section under the microscope: 

 mercuric chloride, if present, will be seen as a fine brown granular 

 deposit, more abundant in the centre of the section than on the 

 outer edges. 



2. Wash with absolute, followed by 90% alcohol. 



3. Immerse for half to two minutes in Solution A. 



4. Wash well with water. 



5. Immerse in Solution B for half to two minutes or until the 

 natural colour of the sections has been restored. 



6. Rinse well with water. 



7. Stain, dehydrate and clear in the usual manner. 



PARAFFIN WAX EMBEDDING AND SECTIONING 



{a) Dehydration 



Technique: 



1 . Pieces of tissue are fixed and washed by any of the standard 

 methods. 



2. Immerse in 50% alcohol from twelve to twenty-four hours. 



3. Transfer to 70% alcohol for the same length of time as 

 stage 2. 



4. Transfer to 90% alcohol for the same length of time. 



5. Transfer to 96% alcohol for the same length of time. 



6. Immerse in absolute alcohol for the same length of time. 



29 



