1900] MICROSCOPICAL JOURNAL [207 



this purpose, and a properly sharpened plane-iron is pref- 

 erable. For embedding, hard paraffin should be used, as 

 it shrinks lees and holds the object more firmly. It will 

 probably roll, but a light pressure with the ball of the 

 finger when cutting will remedy this. The thickness of 

 the sections is a matter of some importance, and the gen- 

 eral tendency is to cut them too thin. If transparency is 

 required, the sections must be bleached, and this requires 

 care, as over-bleaching destroys the fibres of the section, 

 and under-bleaching leaves a blotchy appearance. Mr. 

 King suggests bleaching until the color is discharged from 

 the wood, but no longer, and then a very thorough wash- 

 ing with water. In this connection we think an "anti- 

 chlor" such as hypo-sulphite of soda might be used with 

 advantage, but in any case the final washing must not be 

 curtailed. The stains recommended are Delafield's haema- 

 toxylir, Bismark brown, and for double staining, Grena- 

 diers borax carmine and methyl or aniline green. The 

 hematoxylin is the most generally useful, but is common- 

 ly made in too strong a solution. It is best to stain slow- 

 ly in a comparatively weak solution., and when using the 

 this reigent it is a good plan to wash finally in hard water 

 from a tap, which has a tendency to fix the color. The 

 Bismarck brown is useful for very delicate structure, or 

 for large spiral or scalariform vessels. The double stain- 

 ing is best carried out by immersing the section in borax 

 carmine for twelve hours or more, washing quickly, but 

 well, in 50 per cent alcohol, placing for two or three sec- 

 onds only in aniline or methyl green, washing as before, 

 and then again staining in borax carmine till the red re- 

 appears, changing the supply of stain after the superfiu- 

 ous green is driven out. Mr. King recommends finally 

 mordanting the section in alum cochineal. He gives the 

 needed warning that 95 per cent alcohol will precipitate 

 borax carmine, and that alcohol and hsematoxylin must be 

 kept separate. He recommends that glycerine jelly be 



