BOTANICAL MICROTECHNIQUE 



168. Introduction. This section will describe the technique of a number of 

 well-known histological and cytologioal methods involving the preparation 

 of material. Its object is to present simple and clear descriptions of tried 

 methods that can be depended upon to give good results. Detailed treatments 

 may be found in a number of treatises. ^ The best general accounts of his- 

 tological methods in English are those in Strasburger-Hillhouse, 6, which is 

 based on Strasburger's Das botanische Praktikum. The subject-matter of the 

 following brief account will be taken up under the following headings : 



General reagents employed in temporary preparations. 

 • Some special reagents for microchemical and other tests and temporary 

 preparations. 



Killing and fixing. 



The preservation of material. 



General staining methods. 



Mounting in balsam and glycerin. 



Imbedding in paraffin . 



Sectioning. 



Staining on the slide. 



GENERAL REAGENTS EMPLOYED IN TEMPORARY 

 PREPARATIONS 



169. General reagents employed in temporary preparations. 



A. Iodine solutions. Dissolve 5 grams potassium iodide in 100 cc. distilled 

 water, and add 1 gram of iodine. This gives a good strength for most 

 purposes. It may be diluted if desired, and should be used of half this 

 strength, or weaker, when the color of the solution might interfere with 

 the clearness of vision, as when zoiispores are stained to show their cilia. 

 Iodine solutions kill protoplasm quickly, staining it a deep brown, 

 especially the nucleus and chromatophores. They furnish the simplest 



1 Zimmermann-Humphrey, Botanical Microtechnique, Henry Holt & Co., 

 New York, 189.3. Poulsen-Trelease, Botanical Micro-Chemistry, S. E. Cassino 

 & Co., Boston, 1884. Chamberlain, Methods in Plant Histology, The University 

 of Chicago Press, Chicago, 1905. 



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