Types of Microscope Slides 63 



nation of wholemounts with resin, involves preliminary dehydration and 

 clearing. 



When speed is of more importance than quality, the fresh tissue may 

 be hardened by freezing and cut in this condition. 



The sections, however cut, may be considered as objects to be made 

 into wholemounts. That is, they must, in their turn, be stained, dehy- 

 drated, cleared, and mounted in resin. Even before this, sections cut in 

 wax must have the wax removed and be rehydrated. In diagrammatic 

 form : 



Whole organisms or 

 pieces of organisms 



Freeze 



I 

 Sections cut 



I 

 Stain 



I 

 Examine 



Hardened and fixed 



I 

 Washed 



I 

 Preserved in 



70% alcohol 



1 

 Dehydrated in alcohol 



I 

 Cleared in hydrocarbon 



or oil 



I 

 Impregnated with wax 



i 

 Sections cut 



I 

 Wax removed with 



hydrocarbon 



i 

 Hydrocarbon removed 



with alcohol 



I 

 Sections rehydrated 



with water 



I 

 Stain 



I 

 Dehydrate with 



alcohol 



I 

 Clear in oil or 



hydrocarbon 



I 

 Mount in resin 



These simple outlines must now be expanded by a consideration of the 

 various reagents used before being illustrated by specific examples. 



