Criteria of Successful Processing 



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Fig. 11.1— Comparison of fixation in leaves: a, soybean, Ciaf III, acetone-tertiary 



butvi alcohol: h, cherrv, turgid condition, Craf II, alcohol-xylene; r, cherry, plas- 



molyzed, lAA, alcohol-x)lene; d, red ash, plasmolyzcd, FAA, alcohol-xylene. 



. A Striking illustration of the effects of different killing fluids is 

 afforded by experiments with young leaves of cherry. Figure 11.1 c 

 shows the severe plasmolysis obtained by killing in FAA. Figure 11.1 h 

 shows the turgid, normal condition of the palisade and spongy 

 parenchyma, following killing in a Nawaschin type formula, Craf II. 

 After killing, both lots were processed simultaneously by identical 

 methods, an alcohol-xylene series and careful infiltration in paraffin. 

 Stems are subject to the same defects as the leaves described above. 

 Study Fig. 11.2 a, a cross section of alfalfa stem. Note that the deli- 

 cate hypodermal chlorenchyma is intact, the cells have smooth, 

 rounded outlines, and there is no marked cleavage between cells. 

 Within each chlorenchyma cell the plasma membrane and the chloro- 



