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minutes in alcohol acidulated with two per cent, of nitric acid : 

 then in pure alcohol ; then in the half-grain blue solution before 

 spoken of, from which it should be removed to alcohol ; then to 

 oil of cloves. Much color will be lost in the acid alcohol. The 

 acid is to neutralize the ammonia, which is inimical to aniline blue. 

 Magenta aniline or hsematoxylon may be used with green instead 

 of blue aniline. The brand of green I prefer is the iodine brand, 

 one grain to the ounce of alcohol. 



Double stainings of sections of leaves in which red is first used, 

 have the spiral vessels stained this color, other parts being purple 

 or blue. Radial and tangenital sections of wood have the longi- 

 tudinal woody fibres red, and other parts purple or blue. 



This selection of color is, I think, clue to the fact that spiral 

 vessels and woody fibres take up more red than other parts, and 

 are slower in parting with it. The blue, therefore, seems first to 

 overcome the red in parts where there is less of it. It will en- 

 tirely overcome the red if sufficient time be given. 



If the blue be used before the magenta aniline, the selection of 

 color is reversed. 



I would here call special attention to the importance of examin- 

 ing these stainings at night, as the red in them has a trace of blue 

 in it which does not show at that time, but comes out so decidedly 

 •by daylight, as to change, even spoil, the appearance of the spec- 



I think they should be mounted in Canada balsam, softened 

 with benzole, as the presence of the latter may be beneficial in 

 preserving its magnets. 



I would offer a few words upon section-cutting, and upon pre- 

 paring sections for dyeing. 



To cut a thick leaf, place a bit of it between two pieces of 

 potato or turnip, and tie with a string. Cuts may be made along 

 the midrib, or across it, including a portion of leaf on either side, 

 or through several veins. Fine shavings of wood may be used, 

 or pieces rubbed down.on hones. 



Sections of leaves may be decolored for staining by placing for 

 some time in alcohol; but I would recommend the use of 

 Labarraqne's solution of chlorinated soda, for a few hours after the 

 alcohol. Especially do I recommend the Labarraque for all kinds 

 of wood. In twelve hours wood is generally bleached ; too long 

 a residence in it will, however, often cause it to fall in pieces. 



