MODERN METHODS OP EXAMINATION. 75 



pouring off or filtering the clear fluid. Dr. Beale recom- 

 mends this highly for the preservation of dissections of 

 nerves and morbid specimens. 



Ealfs Fluid. As a substitute for Thwaite's fluid in 

 the preservation of algae. 1 grain of alum and 1 of bay 

 salt to 1 ounce of distilled water. 



Goadby's Solution. Bay salt, 4 ounces; alum, 2 ounces; 

 corrosive sublimate, 4 grains ; boiling water, 4 pints. 

 This is the strength most generally useful, although it 

 may be made stronger or more dilute. It is a useful 

 fluid. If the specimen contain carbonate of lime, the 

 alum must be left out, and the quantity of salt may be 

 quadrupled. 



Dr. Beale discards all solutions containing salts for 

 microscopic purposes, as they render the textures opaque 

 and granular. 



Soluble Glass, or a solution of silicate of soda or potash, 

 or of both, has been proposed, but it is apt to render 

 specimens opaque. 



Chloride of Calcium in saturated aqueous solution has 

 been much recommended, especially by botanists. 



Acetate of Potash, a nearly saturated solution, is useful 

 for vegetable preparations and for specimens of animal 

 tissue which have been stained with osmic acid. The 

 latter do not bear glycerin. 



Pacinian Fluid. This is variously modified, but may 

 consist of corrosive sublimate, 1 part ; chloride of sodium, 

 2 parts; glycerin, 13 parts; distilled water, 113 parts. 

 Sometimes acetic acid is substituted for chloride of so- 

 dium. 



6. CEMENTS. 



Gold Size is recommended by Dr. Carpenter as most 

 generally useful for thin covers. It is made by boiling 

 25 parts of linseed oil for three hours with 1 part of red 

 lead and J of as much umber. The fluid part is then 

 mixed with yellow ochre and white lead in equal parts, 



