84 Specialized Embedding Technics (chap. (S) 



Invert for an hour. Lay l)Ottle on side for an hour, then turn it upright 

 again. Repeat this process until sohition is completed, prol)ahly the fol- 

 lowing day. 



Mounting Sections and Preparing to Stain 



If the sections do not flatten well on slide, but instead want to curl and 

 separate from it, float them on 95% alcohol to soften the celloidin. If 

 there still is a curling prol)lem, soften them a\ ith ether vapor, blot with 

 filter paper and soak on 0.5-1.0% celloidin or nitrocellulose. {Lillie, 

 1954B.) 



If albumen continues to fail as an adhesive agent, try a fresh solution 

 of Masson's gelatine fixative (page 412) under the sections and warm 

 slides on warming plate. As soon as they have spread, remove the slides 

 and allow them to cool for a few mintites. Drain off excess gelatine solu- 

 tion, blot down sections with filter paper and place in formalin vapor 

 overnight (40-50 °C). 



When ready to stain, place the slides in chloroform before proceeding 

 to 95% alcohol. The chloroform will remove the paraffin and harden 

 the celloidin simultaneously. 



Briggs (1958) Double Embedding Method 



1. Fix, wash, and dehydrate through 70%, 95%, and 2 changes of abso- 

 lute alcohol: 2 hotirs each. 



2. Absolute alcohol-ether (50:50): 12-24 hours. 



3. 4% celloidin (or nitrocellulose): 48 hours. 



4. Dip tisstie in alcohol-ether to remove excess celloidin from surface. 

 Harden in chloroform vapor for few minutes. Drop into chloroform 

 and leave until tissue sinks: 12-24 hours. 



5. Infiltrate, 2 changes paraffin: 12-24 hours each. 



6. Embed. 



Briggs suggests that during staining, add ^'5 chloroform by volume 

 to all hydrating and dehydrating solutions above 70% alcohol to pre- 

 vent removal of celloidin. 



Banhy and Clark (1949) Double Embedding Method 



This is similar to the Briggs method with the following modifications: 



For step 3:2 changes nitrocellulose, 3% and 6%. 

 To follow step 4: benzene, overnight. 



