FLUIDS FOB MOUNTING SPECIMENS. 



33 



The preserving fluid should possess the following 

 qualities : — It should be clear and colourless, not apt to 

 become mouldy, or to generate minute Algae ; it should 

 have no action on the specimen, by altering its colour 

 or texture, but should have the property of preserving 

 the natural colour and appearance of the plant for a 

 number of years. 



The fluids recommended by the most practical micro- 

 scopists, are Goadbys preparations ; the composition 

 for the first being " One ounce of bay-salt, half an ounce 

 of alum, one grain of corrosive sublimate, and one pint 

 of boiling water.* To be well stirred, and when cold, 

 carefully filtered through blotting-paper." 



" The second fluid is prepared by pouring one pint 

 and three quarters of boiling water on eight ounces of 

 bay-salt, and one grain of corrosive sublimate ; when 

 cold, to be filtered through blotting-paper." 



Mr. Ralfs, in his beautiful and elaborate work on the 

 Desmidiese, has given the composition of Mr. Thwaites' 

 fluid as follows : — " Sixteen parts distilled water, one 

 part rectified spirits of wine, and a few drops of creo- 

 sote, mixed well together with a small quantity of pre- 

 pared chalk, and then filtered. This is to be afterwards 



* Distilled water, which can be purchased at any re- 

 spectable druggist's, should be used. 



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