Appendix B: Some Standard Reagents and Their Uses 179 



Harden the nervous tissue in Mtiller's (8) or Erlicki's (7) 

 fluid and without previous washing continue the hardening in 

 alcohol. The hardening complete, imbed in celloidin and place 

 the celloidin block into Sol. I for 36 to 48 hours. Place it next 

 into 70 to 80 per cent, alcohol for 24 hours; the block may be 

 left in such alcohol indefinitely. Cut sections in the usual way 

 (not over 20 to 25 microns) and stain them in Sol. II for 24 

 hours at room temperature, and then for a few hours in a warm 

 chamber at 40 C. Wash the sections in water and differentiate 

 (a few minutes) in Sol. Ill until the gray matter (ganglion cells, 

 etc. ) of the tissue becomes yellow. The medullary sheath remains 

 dark. Rinse in water, dehydrate, clear in carbol-xylol, and 

 mount in balsam. This method may be used also for demon- 

 strating degenerated fibers ; they remain unstained. 



53. Light Green (Lichtgrtin S. F.). This is a beautiful cyto- 

 plasmic anilin stain which is frequently used after safraiim as a 

 counterstain. Not more than 0.5 per cent, solution should be 

 used as it stains very rapidly and very deeply. It may be used 

 either as an aqueous or as an alcoholic solution. The writer has 

 found a 0.5 per cent, solution in 95 per cent, alcohol very satis- 

 factory. Sections should remain in it only a few seconds. 



54. Lyons Blue (Bleu de Lyon). This is one of the best of 

 the numerous anilin blues. It is a good contrast stain when 

 used after such nuclear stains as safraiim and carmine. See 

 chap, i, reagent 16. 



Mallory's Connective Tissue Stain. See 30. 

 Magenta, Acid. See 42. 



55. Methylen Blue. This reagent is an extremely useful 

 one; it is of great value in the study of the nervous system, 

 and it can be made to give results with intercellular cement 

 substance, lymph spaces, etc., as satisfactory and with greater 

 certainty than impregnations obtained with gold chloride or 

 silver nitrate. It is also serviceable as an infra vitam stain. 

 Furthermore, methylen blue (saturated solution in 70 per cent, 

 alcohol) followed by eosin is sometimes used for the double 

 staining of blood corpuscles. Methylen blue should not be 

 confounded with methyl blue. 



