224 



Specific Examples of Slide Making 



■ .-■ ..#- ■■"*'* 



153 



154 



Figs. 153 and 154. Details from a bad section prepared by tbe method given in this 

 example. The section appears to have been cut through a node so that the arrange- 

 ment of the parts is hopelessly distorted. The separation of the layers seen at 1 in 

 Fig. 153 (compare 1 in Fig. 151) is a result of both improper dehydration and a 

 blunt knife. The folded tissue seen at 2 is caused by imperfect flattening. The blur 

 at 3 ( Fig. 154 ) is caused by an air bubble left under the section. Notice the im- 

 perfectly stained wall of the vessel at 4 (compare with 3, Fig. 152); at 5 there is 

 hopelessly shrunken cytoplasm (compare 2, Fig. 152). 



being made into a block. The method of preparing the block and cutting 

 sections from it is identical with that used for animal tissues, and the 

 description given in Example 12 may be followed without alteration. 



It will be noticed by reference to Chapter 7 that Johansen's stain re- 

 quires both methyl cellosolve and tertiary butyl alcohol. Neither of these 

 are common laboratory reagents, and their availability should be checked 

 before commencing the technique. There will be required four staining 

 solutions (safranin, methyl violet 2B, fast green FCF, and orange G), 

 three differentiating solutions (which consist of mixtures of various solv- 

 ents in proportions that must be followed closely ) , and one special dehy- 

 drating solution that must be used to avoid removing the stain in the 

 final dehydration. 



The worker thus should have in front of him the following coplin jars 

 of reagents arranged in two rows. The jars in the front row should con- 

 tain xylene, absolute alcohol, 95 per cent alcohol, and 70 per cent alcohol. 

 Those in the back row should contain, in order, the safranin solution, the 

 methyl violet solution, the first differentiating solution, the fast green 

 FCF, the second differentiating solution, the orange G, the third differ- 



