178 THE AMERICAN MONTHLY [June 



lime, two ounces; of common washing soda, four ounces: 

 and distilled water, two pints. Mix the lime in one pint 

 of water and dissolve the soda in the other. Mix the two 

 solutions together, shake well, and let the mixture stand 

 twenty-four hours. Pour off the clear fluid, filter through 

 paper, and keep in a stoppered bottle in a dark place, or 

 cover the bottle with black paper. 



Place sections to be bleached in a bottle of distilled 

 water, and soak them until all trace of spirit is removed, 

 pour off the water and add bleaching fluid, cork up well 

 and let it stand for from one to twelve hours, according 

 to the nature of the specimen. As a rule, the tissue 

 should be quite white, but some parts of sections will 

 never lose all their color, for instance, Rhizome of Pteris 

 aquinila ; in this case, as soon as the hard black schleren- 

 chyma turns yellow, stop the bleaching. Pour off bleach- 

 ing fluid, add water, and keep on changing the water un- 

 til all trace of smell of chlorine is removed, then give a 

 final wash in distilled water, and proceed with the stain- 

 ing, or the sections may be bottled up in methylated 

 spirit until required. 



Staining. — Sections of ovaries and young stems that 

 do not contain much woody tissue, should be stained in 

 hoematoxylin. 



Hoematoxylin 30 grains. 



Absolute alcohol 3}4 ounces. 



Distilled water 3}4 " 



Glycerine 3 



Ammonia alum 30 grains 



Glacial acetic acid 3 drams. 



Dissolve the hoematoxylin in alcohol, and the alum in 

 the water ; then add, to the latter, the acetic acid. Mix 

 the two solutions together, and let the mixture stand for 

 at least a month before use. This stain is rather trouble- 

 some to make. It is better to buy a bottle ready made, 

 as most of the leading opticians supply it. 



