Collection and Preparation 23 



quently renewed until the macerated soft parts are washed away. 



After removal of the animal, mechanical cleaning is next to be 

 undertaken by scrubbing with a fairly stiff brush and by the use 

 of some small, sharp instrument to remove calcareous deposits, worm 

 tubes, or barnacles. Care must be exercised to avoid injury to 

 delicate sculpture. Immersion in one of the several commercial 

 cleaning fluids similar to Javelle water, effectively aids mechanical 

 cleaning by loosening the attachments of limy incrustations. Muriatic 

 acid is useful but must be handled with care on account of its cor- 

 rosive and destructive properties. A solution of one part of com- 

 mercial acid to three parts of fresh water is sufficiently strong for 

 general use. Shells should not be permitted to remain for more than 

 a few seconds m the acid bath before washmg and careful inspec- 

 tion; the bath may be repeated if desired or further application of 

 acid made with a brush interrupted by frequent thorough rinsings. 

 The hands should be protected from contact with the acid. 



After specmiens are thoroughly cleaned and dried, a film of 

 thin oil may be applied to preserve the surface lustre. Shells which 

 have naturally a high polish may have their surfaces protected by 

 a thin coating of colorless lacquer or an aqueous solution of gum 

 arabic, though this is not necessary. The epidermis and valve liga- 

 ments may be kept from excessive drying by soaking the shell for a 

 time in a weak solution of calcium chloride, equal parts of glycerine 

 and water or some other hygroscopic agent. The opercula of uni- 

 valves should be glued to bits of cotton and adjusted in proper re- 

 lation to the apertures of the shells from which they were removed. 

 Bivalve shells may be closed and so maintained until the hinge 

 is dry enough to resist opening, otherwise the valves are quite cer- 

 tain to become separated. 



Chitons are best handled by placing them in a vessel of sea 

 water as collected until they can be extended on a firm surface and 

 held flat by binding or light pressure until well dried; or they may be 

 left in a shallow dish of sea water until quite relaxed when the water 

 is poured off and the chitons allowed to dry slowly. Unless some 

 such method is followed chitons will contract themselves into a 

 veritable ball from which it is impossible to reduce them without 

 injury. 



