126 The Preparation of Microscope Slides 



holder of the hand microtome without additional support. Therefore, 

 it must be held in some substance that itself will cut readily and that may 

 be shaped easily to support the material to be cut. It is perfectly possible 

 to embed the material in wax before cutting a hand section, but if one is 

 to go to this amount of trouble it is usually better to employ a complex 

 microtome of the type described later. Vegetable tissues are generally 

 used to support objects for hand sectioning.. The two best known are 

 "elder pith" and carrots. Elder pith has the advantage that it may be 

 stored indefinitely and cuts with a clean crisp action. Unfortunately, the 

 pith of the American elder (Sambucus canadensis) does not appear to be 

 as suitable for the purpose as the pith of the European elder (S. nigra). 

 This difference between the two species may account for the disfavor 

 in which elder pith is held in the United States, for in the author's 

 experience it is far more convenient than the carrot. The disadvantage of 

 the carrot is that it must be absolutely fresh and, even if it is kept in 

 water overnight, it loses much of that crispness necessary for the pro- 

 duction of a good section. 



Almost all hand sections are cut from botanical material, the majority 

 of them from leaves or stems. To support a leaf, merely cut a cylinder of 

 the right diameter to fit in the microtome from either elder pith or carrot, 

 split it down the middle, insert the leaf (Fig. 89), and then tighten the 

 holder. Stems, however, cannot be held by this means, so that one must 

 obtain a hollow cylinder, having an outer diameter convenient to the 



Fig. 89. Inserting a leaf into a split cylinder of carrot. 



