APPENDIX 229 



Zenker's Fluid: 



Used as a fixing agent for animal tissues. 



Mercuric Chloride 5 grams 



Potassium Dichromate 1 gram 



Sodium Sulphate 1 gram 



Water 100 mils 



Add 5 mils Glacial Acetic Acid before using. 



Time required for fixation is from one to three days. After fixing, 

 the specimen should be washed in running water for at least twelve 

 hours. Transfer to 50 per cent alcohol for three hours, then to 65 

 per cent alcohol and finally to 80 per cent alcohol, to which has been 

 added sufficient concentrated iodine potassium iodide solution to give 

 the alcohol a dark brown color. The purpose of the iodine is to 

 remove traces of the mercurial salts which tend to precipitate in the 

 cells. If the iodine alcohol mixture is decolorized, it must be renewed. 

 After two or three days the material is transferred to fresh 80 per 

 cent alcohol, which is changed frequently until all iodine is removed 

 from the specimen. 



Zinc Chloriodide: 



Zinc Chloride '. 25 grams 



Potassium Iodide 8 grams 



Iodine 1 gram 



Distilled Water, to make 15 mils 



