SECTION ONE 



Petrunkevitch's Cupric Paranitrophenol Fixative* 



Recommended for : 

 Tissues in general. 



Formula: 



Alcohol 60% 100 ml. 



Nitric acid, pure (sp. gr. i*4i — 1-42) 3 ml. 



Ether . . . . . . . . 6 ml. 



Cupric nitrate Cu(N03) 2, 3H2O . . 2 gm. 



Paranitrophenol pure, cryst. . . • • 5 gm. 



Technique: 



Fix material for twelve to twenty-four hours. Wash in 70% 

 alcohol; dehydrate; clear and embed. 



Remarks: 



All stains conmionly in use may be employed after this fixative, 

 which causes less hardening than most other fixatives. 



Regaud's Fluid 



Recommended for : 



Mitochondria and rickettsia in animal tissues. 



Formula: 



Potassium dichromate . . • • 3 gn^- 



Distilled water . . . . . . 100 ml. 



Formalin (formaldehyde 40%) . . 25 ml. 



Technique: 



Fix material for three days changing the fluid every day. Im- 

 merse in 3% potassium dichromate for six to eight days; then 

 wash in running water for twenty-four hours. Dehydrate; clear 

 and embed. 



Remarks: 



Suitable for Giemsa stain and for Masson's trichrome stain. 



Schaudinn's Fluid 



Recommended for : 



Animal tissues in general. Protozoa. 



•A. Petrunkevitch, Science 77, 1 17-18, 1933. 



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