Multiple Staining, &g. By B. Wills Richardson. 871 



wash it in filtered water to remove superfluous scarlet loosely- 

 adhering to the surface, until the water ceases to be in the slightest 

 degree coloured by it. Transfer the section to a half-ounce white 

 porcelain saucer containing spirit of wine coloured bluish green 

 with a couple of drops of aqueous saturated solutions of the green 

 dyes. A drop of each dye about the proper proportion. 



When the section seems dark blue in colour, transfer it to 

 water in another saucer containing a trace of an aqueous saturated 

 solution of arsenious acid, or of a solution of oxalic acid in water 

 (one grain of the acid to an ounce of water), or of glacial acetic 

 acid in water. Wash by rotating the saucer. Then place the 

 section in absolute alcohol, likewise containing a trace of either of 

 the above-named acid solutions. 



When water has had time for removal by the alcohol, which 

 requires from about ten to fifteen minutes, transfer to slide, clear 

 with clove oil, and mount in Klein's or in one of the other dammar 

 solutions. 



The sections of stems submitted to the experiments were cut 

 from the recent stems of (1) sugar cane ; (2) palm ; (3) clematis ; 

 (4) buckthorn ; (5) Ficus Sycamorus and (6) bignonia, all of 

 which were placed at my disposal by my friend Mr. Frederick 

 William Moore, the accomphshed curator of the Grlasnevin Botanic 

 Gardens, near Dublin. 



I have found in practice that sugar-cane sections are most 

 manageable after immersion in the glycerine for several months. 

 These sections, I think, will work more satisfactorily with the 

 atlas-scarlet * and soluble blue than with this scarlet and the green 

 dyes. Should, however, the latter fly, a very beautiful staining in 

 scarlet will remain. (Since this communication was put in type I 

 have successfully stained cane sections in treble, thus : — (1) Atlas- 

 scarlet staining and washing, (2) soluble blue staining and washing 

 in water acidulated with the glacial acetic acid, and (3) iodine and 

 malachite-green staining.) 



Sections of palm are more easy to stain with atlas-scarlet and 

 the green dyes than the sugar-cane sections, these dyes forming 

 exquisitely coloured differentiations of structure in the palm. 



Clematis sections generally come out of the final staining pro- 

 cess coloured in treble, and sometimes the structures stained scarlet 

 in one section may in another be coloured green. 



Buckthorn sections are usually distinctly diSerentiated in 

 scarlet and green. 



Ficus Sycamorus sections seem to have a great affinity for the 

 green stains, a couple of minutes' exposure to their action being 

 nearly sufficient for the completion of the treble staining, and 

 although the green colourings occupy the greater portion of each 



* See ante, p. 573. 



