11 



Sections of Free Material 



General Principles 



Nature of the Process 



A section is a thin slice cut from biolog- 

 ical materials with a view to studying 

 either the cells themselves, or their ar- 

 rangement, neither of which can well be 

 made out from a wholemount. If the 



Though sections may be cut at any an- 

 gle, they are usually taken through one of 

 three planes (see Fig. 33), known as trans- 

 verse, sagittal, and frontal. The purpose of 

 this orientation of the material with rela- 

 tion to the plane of the section is to permit 



Fig. 33. Standard section planes. 



worker's only interest is, in the shape of 

 the cells, as distinct from their structure, 

 he should attempt some of the prepara- 

 tions described in Chapter 9, which will 

 often be found better than sections for his 

 purpose. 



a better visuahzation of the structure of 

 the whole, from an examination of sec- 

 tions. When the relation of organs is to be 

 reproduced from sections, the process is 

 known as reconstruction and is referred to 

 briefly in Chapter 14. In theory a section 



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