SECTION TWO 



Results: 



With the aqueous solution of the stain 



Medusa of Obelia and limbs of crustaceans are stained deep 

 carmine colour. The finest structures of ostracod appendages, 

 uniform pink, but a better effect can, however, be obtained by 

 staining the specimen for a longer period (up to sixteen hours) 

 with a solution of the dye in benzyl alcohol : the final result in this 

 case is a definite purple for the exoskeleton, while the other tissues 

 are carmine colour. 



Reference: Cannon, H. G. (1941),^. R. Mic. Soc, series III, 61, parts 3 and 4. 



LITHIUM SILVER (Laidlaw) 

 For staining skin and tumours 



Solutions required: 



A. Iodine 1% in absolute alcohol. 



B. Sodium thiosulphate 5% aqueous. 



C. Potassium permanganate 0-5% aqueous. 



D. Oxalic acid 5% aqueous. 



E. Lithium silver: 



Dissolve 12 gm. silver nitrate in 20 ml. distilled 

 water in a 500 ml. stoppered bottle ; then add 230 ml. 

 lithium carbonate, saturated, aqueous, and shake well. 

 Transfer to a 250 ml. measuring cylinder; cover with 

 a watch glass and allow to stand undisturbed until 

 the precipitate formed measures about 70 ml. Pour 

 off the clear liquid and transfer the precipitate to 

 another vessel. Wash precipitate with three or four 

 changes of distilled water, decanting after each 

 washing so that the precipitate remaining measures 

 70 ml. Add a diluted ammonia solution (15 ml. 

 strong ammonia solution, sp. gr. 0-880 diluted with 

 35 ml. distilled water) a little at a time until the fluid 

 precipitate is almost clear. Filter through a Whatman 

 No. 40 filter paper. 



F. Formalin 1% in tap water. 



G. Gold chloride (yellow) 0-5% in distilled water. 



Technique: 



1. Fix tissues in 10% formalin for three days. 



2. Dehydrate, clear, embed in paraffin wax in the usual manner. 



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