SECTION ONE 



C. Gelatine 15% 



Phenol 1% aqueous . . . . 85 ml. 

 Gelatine . . . . . . • • 15 gm* 



Prepare exactly as for Solution A, except that 

 temperature should be raised to about 75° C. before 

 filtering. 



D. Gelatine 20% 



Gelatine . . . . . . . . 20 gm. 



Phenol 1% aqueous . . . . 80 ml. 



Prepare as for Solution A, but raise temperature 

 to 95° C before filtering. 



E. Gelatine 1% 



Gelatine . . . . . . . . i gm. 



Phenol 1% aqueous . . • • 99 rnl. 



Dissolve by warming. 



Technique: 



1. Small pieces of tissue, not more than 3 mm. in thickness are 

 fixed for twenty-four hours in 5% formalin in physiological saline. 



2. Wash in running water. 



3. Inmierse in 5% gelatine in an incubator at 37° C. for twenty- 

 four hours. 



4. Immerse in 10% gelatine overnight in an incubator at 37° C. 



5. Immerse in 15% gelatine in an incubator for several hours 

 at 37° C. 



6. Embed in 20% gelatine and leave to set. 



7. Cut out blocks of tissue and immerse them in formalin for 

 twenty-four hours. 



Note: The blocks may be stored indefinitely in this formalin 

 solution if desired. 



8. Rinse blocks in water and trim. 



9. Freeze blocks thoroughly until they are uniformly white. 



10. Allow the block to thaw somewhat until the knife cuts 

 easily. 



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