APPENDIX II 475 



longitudinal. This is done by means of a razor, hollow 

 ground or with one flat side. The object and razor should 

 be wetted, and the latter dipped in alcohol to prevent air 

 bubbles. The blade and handle should be in the same 

 straight line held in the right hand, the object in the left 

 between the thumb and first finger, the razor edge being 

 towards one. Rest the left wrist and forearm on the table, 

 and the blade against the left forefinger ; draw the razor 

 with a sliding motion towards one with a long stroke. This 

 applies to larger objects, but, if they are small, they may be 

 fixed in a slit in a piece of elder pith ; or if a microtome or 

 mechanical section cutter is used, and the object is small, the 

 latter may be embedded in paraffin wax, or solid paraffin 

 2 parts, vaseline i part, which is easily melted, and the 

 object is inserted, washed in alcohol beforehand, in a cavity. 

 The melted wax is poured into the cavity so that it covers 

 the specimen. When the wax is cold the object may be 

 sectioned as above, a series being taken and cut ribbon 

 fashion. White of egg may also be used as an embedding 

 medium, whilst spores, etc., may be embedded in gum laid 

 on a piece of pith. In order to free the sections from the 

 embedding material, carbolic acid and turpentine are used 

 to dissolve wax, glycerine and water dissolving gum. 



When thus freed the sections are transferred to a watch 

 glass, with a camel-hair brush or water jet, containing a 

 little alcohol or water, and are ready for mounting. 



Take a glass slide and cover-glass, which must be quite 

 dry and clean, heated perhaps with sulphuric acid if filmy, 

 then washed. Determine what mounting medium be used 

 beforehand — e.g. glycerine, caustic potash, eau de Javelle, 

 chloral hydrate, phenol — the first being used as a permanent 

 mounting medium, the others as clearing reagents. It should 

 also be determined what staining solution is to be used, 

 if any. 



