150 Modern Microscopy 



sanranin mixed with an equal quantity of aniline water for 

 two days. The tissue is then to be washed in distilled 

 water. It is then soaked in absolute alcohol until the 

 colour is removed from everything except the nuclei. It is 

 then again rinsed in water and placed in a saturated watery 

 solution of gentian violet for two hours, washed again in 

 distilled water, decolourized in alcohol until only the nuclei 

 are left stained ; then transfer to bergarnot-oil, and mount 

 in xylol balsam. 



Weigert-Pal Method for the central nervous system, by 

 which all medullated fibres are stained darkly, while the 

 grey substance and any sclerosed tracts of white matter are 

 left uncoloured. Pieces of brain or spinal cord which have 

 been hardened in Mliller's fluid are to be placed direct in 

 gum-water and syrup and soaked for a few hours; then 

 make sections with a freezing microtome, and place them 

 in water, and from this transfer to Marchi's fluid, as 

 follows : 



Mliller's fluid 2 parts, 



Osmic acid, 1 per cent. ... ... 1 part, 



and soak for a few hours. They are then washed in water 

 and transferred to the following stain : Dissolve 1 gramme 

 of haematoxylin in a little alcohol, and add to it 100 c.c. of 

 a 2 per cent, solution of glacial acetic acid, in which leave 

 the section for twelve hours ; it will then be quite black. 

 Wash again in water, and place in a J per cent, solution of 

 potassic permanganate for 5 minutes ; rinse with water and 

 transfer to Pal's solution (sulphate of soda 1 gramme, oxalic 

 acid 1 gramme, distilled water 200 c.c.), and bleach for a 

 few minutes. When sufficiently bleached they are passed 

 through water into alcohol, cleared in bergamot-oil, and 

 mounted in Canada balsam. 



