in concentrated solution in fresh or sea water, either cold or 

 hot. In manipulations with sublimate, metallic implements 

 must not be used, because they decompose the solution and stain 

 the preparations. The solution is made, when possible, with 

 hot water for economy of time, and in vessels of glass or por- 

 celain. Care must be exercised to avoid boiling the sublimate 

 in open vessels, and not to inhale the vapors. The hands must 

 not be immersed in the solution if they have on them open cuts 



or sores. 



All animals which have been prepared with this reagent 

 can be used for histological researches. Corrosive sublimate 

 is also used mixed with acetic or chromic acid or with sulphate 

 of copper. Animals which have been treated with corrosive subli- 

 mate must be washed carefully and thoroughly in fresh water be- 

 fore they are placed in alcohol. Add a solution of iodine drop 

 by drop until the alcohol remains permanently colored thereby; 

 this insures the entire removal of crystals of corrosive subli- 

 mate from the substance of the animal. If this precaution is 

 not taken, the mercury will be reduced from the corrosive sub- 

 limate and will stain the animal black, forming a black pre- 

 cipitate on the sides and bottom of the vessel. The amount of 

 iodine to be used depends upon the size and character of animal 

 to be treated. 



Bichromate of potassium . — This is used as a 5 per cent 

 solution for slowly hardening gelatinous animals without render- 

 ing them too fragile, when it is not possible to work with 

 chromic acid. On account of the troublesome precipitate which 

 forms when objects treated with bichromate are transferred to 

 alcohol, the use of this reagent is not recommended. For bleach- 

 ing the preparations before they are put into alcohol, use a few 

 drops of concentrated sulphuric acid. 



Sulphate of copper . — This is used only in solutions from 

 5 per cent to 10 per cent strength, which are made with hot fresh 

 water, and used alone or mixed with corrosive sublimate for kill- 

 ing larvae and delicate animals. The objects which have been 

 treated with this reagent must be washed repeatedly with water or 

 else they will not remain perfectly clear, owing to the formation 

 of crystals within the tissues, which render them opaque. If they 

 afterwards prove to have been washed too little, the objects 

 should be treated several times with an acid. 



Chloral hydrate . — This is used in very weak solution, from 

 0.1 to 0.2 of 1 per cent made fresh in sea water, for narcotizing 

 several forms before fixing them. This method has the advantage 

 that, if the animal after a certain time does not remain in the 

 condition desired for preservation, it can be replaced in sea 

 water, where it will regain power of motion and continue to live. 

 It is used for killing animals which live in the crevices of a 



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