UNITED STATES DEPARTMENT OF AGRICULTURE 



MISCELLANEOUS PUBLICATION No. 679 



WASHINGTON, D. C. JULY 1949 



Preservation of Agricultural Specimens 

 in Plastics 



By G. R. Fessenden, formerly specialist in agricultural specimen preservation, Bureau 

 of Agricultural and Industrial Chemistry, Agricultural Research Administration 



CONTENTS 



Page 

 Introduction iii 



Part 1 



Preservation of natural color in plant specimens mounted in plastic plates 1 



Equipment and supplies 1 



Types of preserving fluids and their principal characteristics 4 



Collection, storage, and preliminary preparation of specimens 6 



Processing the specimen for natural color preservation 7 



Preserving and laying out the specimen 14 



Dehydration and preparation for mounting 21 



Mounting between plastic sheets 24 



Care of finished mounts 29 



Part 2 



Embedment of biological specimens in plastic blocks 30 



Equipment and supplies 32 



Properties of methyl and ethyl methacrylates 34 



Preparation of plastic 36 



Selection of specimens 45 



Preparing specimens for embedment 46 



Casting supporting bases for specimens 58 



Embedment of specimens 60 



Finishing the castings 65 



Care of finished mounts 69 



Literature cited 71 



Patents 72 



Selected bibliography 



