FIXATION 727 



Tellyesniczky's Fluid: 



Potassium bichromate 3 grm. 



Water 100 c.-c. i 



Glacial acetic acid (added just before use) 5 c.c. 



Pieces of tissue are placed in a considerable volume of the fixing 

 fluid and left for three to seven days. They are then washed in run- 

 ning water for twelve . to twenty-four hours, and hardened in graded 

 alcohol. (Where tissues are first washed in water, the graded alcohols 

 must begin with the 50 per cent, strength.) This fluid yields excellent re- 

 sults with muscular and glandular tissues, and is particularly serviceable 

 where pieces of considerable size must be used, e.g., whole embryos. 



Orth's Fluid (Muller-formol) : 



Muller's fluid 95 to 90 c.c. 



Pure formalin 5 to 10 c.c. 



This is an excellent fixative for general use, for by it most tissues 

 are well preserved. Small pieces of tissue are left in a considerable 

 volume of the fluid for one to five days, washed thoroughly in running 

 water for twelve to twenty-four hours, and hardened in graded alcohol. 

 The washing should be so thorough as to remove all excess of the 

 chromium compounds, otherwise difficulty will be experienced in obtain- 

 ing satisfactorily stained preparations. 



Chrom-Acetic-Formalin Mixture. This makes an excellent fixing 

 fluid for general embryologic work. 



Mix and keep in stock the following solution: 



1 per cent, chromic acid 16 volumes 



Glacial acetic acid 1 volume 



At the time of using add to 2 volumes of the stock mixture, 1 volume 

 of formalin. 



Wash in water from twenty minutes to two hours according to size. 

 Zenker's Solution: 



Potassium bichromate 2.5 grm. 



Sodium sulphate 1.0 grm. 



Mercuric chlorid 5.0 grm. 



Distilled water 100.0 c.c. 



Just prior to use add 1 c.c. of glacial acetic acid to each 20 c.c. of the 

 fluid. 



