Timing Schedule for Paraffin Method 41 



simpler and safer ^vay involves passing the THF through a column of 

 activated alumina. 



Timing Schedule for Paraffin Method 



Size 10 ± mm. — smaller pieces will require less time, larger pieces 

 more time. 



Schedule Using Ethyl Alcohol 



1. A general fixative: overnight or 24 hours. (Bouin's, Susa's, Stieve's, 

 Formalin, Zenker's^) 



2. Wash in water, running if possible; 6-8 hotirs or overnight. Excep- 

 tions: Bouin's, Susa's and Stieve's fixed tissue can be transferred 

 directly to 50 or 70% alcohol without washing. 



3. Transfer to 50% alcohol: 1 hour. 



4. Transfer to 70% alcohol: 1 hour. 



(See special iodine treatment for mercuric chloride fixatives, page 

 12) 



5. Transfer to 95% ethyl alcohol: 1 to H hours. 



6. Transfer to absolute ethyl alcohol #1: ^ to 1 hour. 



7. Transfer to absolute ethyl alcohol #2: ^ to 1 hour. 



8. Transfer to toluene #1 : i to 1 hour. 



9. Transfer to toluene #2: \ to 1 hour. 



10. Transfer to melted paraffin #1: 1 to 1 hour. 



11. Transfer to melted paraffin #2: I to 1 hour. 



12. Embed. 



Alternate Schedule Using Isopropyl Alcohol 

 (steps 1 through 4 the same as above) 



5. Transfer to isopropyl alcohol 4^1 : i to 1 hour. 



6. Transfer to isopropyl alcohol #2: ^ to 1 hour. 



7. Transfer to toluene #1: 1 to 1 hour. 



8. Transfer to toluene #2: h to 1 hour. 



9. Transfer to melted paraffin :#:1 : i to 1 hour. 



Mf tissue fixed in Zenker's tends to harden, do not leave it overnight in the fixative: 

 transfer to 3-5% aqueous potassium dichromate for overnight, then proceed as usual on 

 schedule. 



