Method VII 



49 



sity for the low temperature in fixing may be avoided. After 

 staining and exposure to the air, the pieces of tissue are first 

 placed for 10—15 minutes in the saturated aqueous solution of 

 ammonium picrate (C, l) as a preliminary fixing fluid. Without 

 washing, the tissue is then transferred to 15—20 volumes of 

 Bethe's fixing fluid (C, 2) for about i hour. The Bethe's 

 fluid should acquire a temperature as low as that of the ordinary 

 room before using, but does not need to be on ice. 



After fixing, the pieces of tissue are washed in water, 

 dehydrated, cleared, and imbedded in paraffin, as directed 

 above. 



With regard to the necessity that the tissues be fresh in 

 order to stain by the intra vitam methylen-blue method, it is 

 agreed by all that the fresher the tissues the better. However, 

 Dogiel' found that sympathetic ganglia of the human heart, as 

 well as some of the sensory axones of that organ, may be stained 

 by the method several hours after death. 



• A. S. DoGIEL, " Zur Frage iiber den feineren Bau der Herzganglien des 

 Menschen und der Saugethiere," Archiv fur mikros. Anat., Bd. LIII, p. 237, 1898. 



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