Mounting 



59 



Figure 15. Compressed or folded paraffin sections. 



when the ribbon is floating on the water on the slide, but not while it 

 is warm, or the paraffin will stick to the dissecting needles. Have the 

 slide cool and split away the paraffin with care so that the tisstie is not 

 injured (Figs. 15, 16, and 17). A rather violent method for straightening 



Figure 16. Breaking paraffin with dissecting needles to permit ribbon ex- 

 pansion without folds. 



stubborn ribbons is the addition of some acetone or alcohol to the water. 

 Slides that do not take the Avater smoothly may be dirty slides, but it 

 is more likely that the albumen was omitted. Excessive heat for flatten- 

 ing may cause shrinkage of cell structures and tearing and displacement 



Figure 17. Expanded and flattened paraffin sections. 



