THE PRESERVATION OF MATERIAL 373 



therefore, to sponge the animal with a preserving fluid which will 

 penetrate the coat immediately, or if many specimens are being 

 prepared, to immerse the whole animal for a moment. A suitable 

 fluid for this purpose is formalin-alcohol, made by adding 2 per cent 

 of formalin to a mixture of equal parts of ordinary spirit and water. 

 The alcohol ensures immediate penetration and assists the formalin 

 in preservation. The fluid should be squeezed out of the coat so 

 far as practicable. An excess is undesirable because the alcohol 

 tends to withdraw fluid from the body if the animals are kept for 

 some time before dissection, but more especially because the fluid 

 is likely to get into the material during dissection where it has the 

 effect of removing glycerin, so that the tissues become brittle and 

 dry rapidly on exposure. 



For the storage of material, either before or during dissection, 

 no precaution is necessary except that of protecting the body from 

 undue exposure to evaporation. The animals may be stored in a 

 spirit tank if raised above the level of the fluid, or may be kept 

 individually in special prepared boxes for convenience in the 

 laboratory. A zinc-lined copper box with sliding top, or a paraflin- 

 wax-lined galvanized box with slip over cover, of dimensions 

 7 X 7 X 24 inches, will be found to be adequate and of proper 

 proportions for animals of average size. If less costly individual 

 containers are required, ordinary water-proofed paper sheets or 

 bags may be employed, the latter being now obtainable through 

 regular trade channels. 



