Mojinfiiig: 65 



■^) 



and Hewitt [19^2) support the tissue with Kodak Frozen Section Film. 

 The film is softened in water, excess moisture sponged off, and the fihii 

 pressed do^vn on the freshly cut surface of the frozen tissue. The film 

 freezes and adheres to the tissue while a section is cut; this is carefully 

 raised as the knife passes under it. The film wath the section is laid face 

 down on a slide. As the section thaws, it will cling to the slide, and a 

 thin layer of moisture develops by capillarity between it and the film. 

 When this has dried, the section can be stained. (Also see use of cellu- 

 lose tape, page 394.) 



Mounting 



If the sections are collected in a glass dish, place the dish on a black 

 stirface — a table top or a piece of black paper. The sections are more 

 easily manipulated over the black backgrotmd and the best ones can be 

 selected. Dip one end of an albumenized slide into the water. W^ith a 

 needle or preferably a small round-tipped glass rod, gently bring a sec- 

 tion against the slide. Hold the section at one corner; by maneuvering 

 luider ^vater creases can be imfolded and the section unrolled as the 

 slide is drawn out of the solution. If the wrinkles refuse to straighten, 

 drop the section on 70% alcohol and then remove it to a slide. Drain 

 off excess w^ater or pull it off ^vith filter paper. Press section in place 

 W'ith filter paper moistened with 50% alcohol. With a pipette add ab- 

 solute alcohol directly on top of the section; let stand for approximately 

 30 seconds. Replace with more absolute alcohol (mtist be ethyl alcohol). 

 Drain thoroughly, and flood slide with 1% nitrocellulose (dissolved in 

 absolute ethyl alcohol-ether, 1:1) for 1 second. Drain off and wave slide 

 in air until almost dry. Immerse in 70 or 80% alcohol, 5-10 minutes or 

 longer (can be left here for several hotirs or days). Caution: use an old 

 solution of alcohol, either one from the staining series, or one which 

 has been mixed for at least a day. A freshly prepared solution forms bub- 

 bles between section and slide. 



Fresh tissue sections may be removed from normal saline to the slide 

 and thorotighly drained. Add 95% alcohol to remove the water; let stand 

 30-60 seconds. Drain off and allow the section to almost dry. Place in 

 95%, alcohol for 1-2 minutes and proceed to stain. 



A gelatine fixative can be used to affix the sections. Spread fixati\e on 

 the slides and dry them in an incubator. (They can be stored for some 

 time in a dust-free box.) Float the sections on the gelatine, drain off 



