ORDER OF PROCEDURE IN MAKING MICROSCOPICAL PREPARATIONS BY 

 THE PARAFFIN METHOD. 



§ 284. It will be seen from this table and from sections 268 to 283 

 that it requires from 7 to 10 days to get a microscopical preparation by 

 the paraffin method if one starts with the fresh tissue. Depending on 

 the method of fixing and hardening, the time may be much greater. 

 Unless -much time is lost in waiting one must plan ahead in histological 

 work. 



1. Fixing and hardening the tissue or 



organ (§ 269), 4 days or more. 



2. Dehydrating the object to be cut in 



95% or stronger alcohol (§ 270), 5 

 to 24 hours. 



3. Saturating the tissue with chloroform 



($ 271), 4 to 24 hours. 



4. Infiltrating the tissue with chloroform 



paraffin ({S 272), 3 to 10 days. 



5. Imbedding in pure paraffin (§ 273), 



10 minutes. 



6. Cutting the sections (§ 274), 10 min- 



utes. 



7. Fastening the sections to a slide 



(§ 275), 5 minutes. 



8. Removing the paraffin (§ 276), 10 



minutes to 24 hours. 



9. Washing in 95% alcohol to remove 



the benzin (\ 277), 2 minutes. 

 10. Staining with an alcoholic or aque- 

 ous dye (§ 278-279), 2 minutes to 24 

 hours. 



11. Washing away the superfluous stain, 



(3 278-279). 



12. Staining with a general dye ((! 280), 



10 seconds to 10 minutes. 



13. Washing the sections with water or 



alcohol ($ 280), 3-5 minutes. 



14. Dehydrating the stained sections in 



95% alcohol (<> 281), 5 minutes to 

 24 hours. 



15. Clearing the sections (J 282), 5 min- 



utes to 24 hours. 



16. Mounting in balsam (I 283), 2 to 5 



minutes. 



17. Sealing the cover-glass (§ 238), 2 



minutes. 



18. Labeling the preparation 



minutes. 



19. Cataloging the preparation ( 

 5 to 10 minutes. 



291), 2 

 294), 



