APPENDIX 301 



Pieces of the nervous system are hardened in this fluid in 

 about a fortnight ; they are then washed with water, placed in 

 alcohol and iodine solution, and then in alcohoL 



Mercuric chloride and alcohol. A saturated solution of 

 mercuric chloride in 75 to 95 p.c. alcohol. 



Formol, alcohol and chromic acid (Marina). 



90 p.c. alcohol 100 c.c. 

 Chromic acid 5 c.c. 



Shake now and then till the chromic acid is dissolved, add 5 c.c. 

 of formol when required for use. 



This has been recommended when it is desired to stain 

 sections of the central nervous system by different methods. 



Small pieces of tissue are hardened in 1 to 2 days. If large 

 pieces are taken, they are cut into slices after a day, the fluid 

 renewed in this and the following day ; hardening will be 

 complete in about a week. 



The pieces may be fixed to a block and cut unimbedded, the 

 razor being moistened with 90 p.c. alcohol. Sections may then 

 (a) be stained by Nissl's and similar methods, (6) placed in 

 3 p.c. potassium bichromate for a day, and (a) treated by 

 Weigert's method, or (6) stained with picrocarmine etc., (c) placed 

 in chromogen solution (cp. p. 247) and stained by Weigert's 

 neuroglia method. 



Chrome alum and acetate of copper (Weigert's fluid). 



Chrome alum 2 '5 grm. 



Acetate of copper 5O grm. 

 Ordinary acetic acid 5*0 grm. 

 Formol 10 c.c. 



Water 77'5 c.c. 



Boil the chrome alum in water ; when it is dissolved remove 

 from the flame, add the copper acetate in fine powder and the 

 acetic acid, stir well, let cool, and filter. Add then the formol. 



The hardening is complete in about 



The mixture as given above is 

 stain (p. 247). V ^ 



UBRAR 



