PART III 



CHAPTER XLVI 



BOTANICAL TECHNIQUE * 



GENERAL METHODS OF FIXATION IMBEDDING 

 SECTIONING AND MOUNTING 



1233. Introductory. The fundamental methods described for 

 animal tissues are in general equally applicable to those of plants. 

 No special killing agents are required ; the fixative fulfils this 

 function. Plant material must be kept in first-class condition 

 until it can be studied or fixed and preserved. Just prior to 

 killing, portions for examination should be cut free of unwanted 

 parts and immediately immersed in the fixative. Further trim- 

 ming is best done below the surface of the liquid. 



Better results usually accompany the use of more careful 

 treatments, provided that effective reagents are used in every 

 stage from fixation to the final mount. No amount of later care 

 can correct inadequate fixation . It is only too evident that in both 

 histological and cytological work many fallacious observations 

 are traceable to insufficient care during the early stages of treat- 

 ment of the material upon which the observations are later 

 based. Less exacting methods are, of course, permissible providing 

 it is clearly recognised that only limited demands can be made 

 upon the finished product. For validity of fixation images 

 see § 1355. 



General references : Belling, The Use of the Microscope, 1928 ; 

 Chamberlain, Methods in Plant Histology, 5th ed., 1932 ; Dop and 

 Gautier, Manuel de technique, histologie et microbie vegetates, Paris, 

 1928 ; Kisser, Botanische Mikrotechnik, Jena, 1926 ; Krause, 

 Enzyklopadie der mikroskopischen Technik, 3rd ed., Berlin, 1926 ; 

 Rawlins, Phyiopathological and Botanical Research Methods, Wiley, 

 1933 ; Schneider-Zimmerman, Die botanische Microtechnik, Jena, 

 1922 ; Smith, Trans. Amer. Micr. Soc, xxxiv, 1915, p. 71 (historical) ; 

 Taylor, General Botanical Microtechnique (in McClung, Microscopical 

 Technique, 1929). 



1234. Fixatives. For rough anatomical work, in which the cell 

 wall structure is most important, fix and preserve in 4 per cent, 

 formalin or 70 per cent, alcohol. Carnoy and saturated alcoholic 



* By D. G. C. 



620 



