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X. — On a Blue and Scarlet Double Stain, suitable for Nerve and 

 many other Animal Tissues. By B. Wills Kiohardson, 

 F.B.C.S.I., Vice-President University of DubKn Biological 

 Association. 



{Read 9th June, 1881.) 



The following method of double- staining sections in l3lue and 

 scarlet, and sections of the spinal cord in particular, I have found 

 very satisfactory. The differentiation of many of the component 

 parts of the cord, for example, being decided and most instructive, 

 the cells being blue or bluish-grey with darker shaded nuclei, the 

 axis cylinder of each conducting fibre being also of the darker tint, 

 while the white substance of Schwann is scarlet modified a little in 

 brilliancy by the adjoining bluish tints. 



For conciseness' sake, I shall take one section through this 

 double-staining process : — 



Place a section sliced from the hardened spinal cord, say of an 

 ox (prepared according to one of the ordinary methods followed by 

 microscopists), in a bottle about half-filled with a deeply tinted 

 watery solution of Atlas scarlet, made by adding drop by drop 

 to filtered water a very deeply coloured solution of the scarlet in 

 Price's glycerine. To the watery solution a few drops of alcohol 

 may be added. Short wide-mouthed pomatum half-ounce bottles 

 with good corks are excellently suited for staining purposes. 



Examine the section from time to time, say every third day, 

 and when found to be stained of a deep scarlet tint, it is ready for 

 the second stage of the process. Sections, however, may be left in 

 the solution for many weeks without risk of becoming too dark for 

 this stage. 



Take the section from the bottle, and wash it in methylated 

 spirit to remove any of the scarlet stain that may be loosely 

 adherent to the surface. The small white saucers (ounce) used by 

 artists in water colours are very useful for section-staining, and 

 other microscopic purposes. 



When washed, place the section in a second saucer containing 

 a blue watery solution, made by adding a drop or two of a deep- 

 coloured solution of soluble blue in glycerine, to filtered water. 



This is a critical stage of the process, for if left too long in the 

 blue fluid, the double-staining will not be satisfactory. 



From fifteen to twenty minutes I have usually found sufficient 

 for the purpose. The thinner the section, the more rapid the 

 action of the blue stain. 



When sections have been in the blue fluid for a few minutes, 

 the blue generally shows signs of fading ; to check which, add a 

 Ser. 2.— Vol. I. 2 Q 



