182 Animal Microloyy 



time under the microscope and when the nerve elements are well 

 stained, fix in ammonium picrate and proceed as in 6). In case of 

 the central nervous system, fairly good results may sometimes be 

 obtained by dusting the methylen blue powder over the freshly 

 cut surface of the part to be studied. The development and 

 fixing of the color is the same as in 6 ) . 



c/) Nissl's Method of Staining Basophil (Tigroid) Substance in 

 Nerve Cells. 



Methylen blue 3.75 grams 



Venetian soap (white castile soap) . . 1.75 grams 

 Water 1,000.00 c.c 



It is best to keep the stain for some months before using, 



Ganglia should be fixed in alcohol, formalin or corrosive subli- 

 mate and sectioned in paraffin. Fix the sections to the slide, dis- 

 solve out the paraffin with xylol, and run the preparation down to 

 the aqueous stain in the ordinary way. In a test-tube heat a few 

 cubic centimeters of the stain until it steams, then apply it while 

 still warm to the sections on the slide, which has been placed flat 

 on the desk. It takes about 6 minutes for the stain to act. Pour 

 off the surplus stain and rinse the slide in distilled water. Lay 

 it flat 011 the desk again and flood the sections with anilin-alcohol 

 (95 per cent, alcohol, 9 parts; anilin oil, 1 part). Let the sec- 

 tions decolorize (20 to 30 seconds) until they are a pale blue; 

 then drain off the anilin-alcohol and transfer the preparation to 

 absolute alcohol. Clear in xylol and mount in balsam. The 

 basophil granules should appear deep blue in color. They are 

 arranged for the most part concentrically around the nucleus. 



e) Unna's Method of Staining Unstriated Muscle in Sections. 

 Stain in a 1 per cent, aqueous solution of polychromatic methylen 

 blue, rinse in water and then leave for 10 minutes in a 1 percent, 

 aqueous solution of potassium ferricyanide. Transfer to acid 

 alcohol until sufficiently decolorized, then complete the dehydra- 

 tion and mount in the usual way. 



/) For Ordinary Section Staining where a nuclear stain is 

 desired, methylen blue answers very well. It is usually used (2 

 to 24 hours) in aqueous solution. The treatment is the same as 

 for safranin. 



