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Glycerine. This may be used, with special precautions, to 

 preserve the natural colour of an animal. But as this reagent 

 produces strong shrinkage in the tissues, it is essential to transfer 

 the specimen into it gradually. This can be done by using 

 successively stronger solutions of glycerine. The specimen may 

 first be placed in a 10 per cent, solution of formalin containing a small 

 quantity of glycerine. After a suitable interval (perhaps half an 

 hour) the specimen, now hardened by the formalin, may be placed 

 in a stronger solution of glycerine in water ; and this process 

 must be repeated each time with an increasing strength of 

 glycerine. If the colour is not too fugitive, the specimen may be 

 hardened in alcohol for a short time, transferred to a dilute 

 solution of glycerine in alcohol, and then left in an open dish for 

 the glycerine to concentrate itself by evaporation. In a hot, dry 

 climate a formalin solution of glycerine might be allowed to 

 concentrate itself in the same way. 



Whatever method is adopted, the specimen should be brought 

 into glycerine of full strength before the colour is lost. 



Iodine, tinctuee of. A small quantity of this will be useful 

 (see " Corrosive Sublimate "). 



Sodium Chloride (common salt). A weak solution of this 

 substance should always be kept ready to hand for the preliminary 

 washing of parasitic worms. 1 gramme of salt dissolved in 99 

 cubic centimetres of water will give the required strength (or about 

 1 oz. in 5 pints). 



APPAEATUS. 



A few dissecting instruments will be required by those who 

 intend to look for parasites. They need not be many or costly, 

 but the following would be indispensable : — 



Forceps. — Two or three pairs of various sizes, including one 

 large and strong pair, and one with slender points. 



Scissors. — A large strong pair for cutting open animals (some- 

 times better than a knife). One or two pairs of smaller 

 dissecting scissors. 



Scalpels. — Three or four of different sizes and shapes. 



Needles. — A few of different sizes mounted in wooden handles. 



Camel's hair brushes. — One or two. 



Glass vessels. — Specimen tubes, with corks, of various sizes, 

 will be required, and can be obtained cheaply from dealers 

 in natural history requisites. 



