548 



APPENDIX 



Metal and plastic cages are used in most colonies. Stainless steel is the most durable 

 and most expensive metal, aluminium alloys are intermediate in cost and durability, 

 and tinned or galvanized iron is the least expensive and most susceptible to the corrosive 

 effects of urine. Various kinds of plastics are being used for construction of cages. 

 The transparent plastics are desirable because of the convenience they provide in allow- 

 ing observation of the animals. Such plastic materials, however, cannot withstand 

 high temperatures and are quite fragile. Molded fiberglass cages are more durable, 

 but are not transparent. Plastics are also easily scratched or chewed so that efficient 

 cleaning eventually becomes a problem. 



Fig. 88. Clean stainless steel cages stacked on dolly. 



Two kinds of cages are in use in our colonies: (1) stackable two-compartment stain- 

 less steel cages and (2) two-compartment transparent plastic cages which are also stack- 

 able. Only a few are of the latter type. Each half of the two-compartment cage 

 has a floor dimension of 4 by 11 inches. The walls are about 6 inches high. Each 

 compartment provides adequate space for 5 adult mice or a mated pair with a litter. 



The steel cages are made of a single, seamless, deep-drawn sheet of metal. It has 

 rounded corners and a polished surface. The cage is practically indestructible, easy 

 to clean, and can be autoclaved or washed at very high temperatures. It is impervious 

 to the corrosive effects of urine, feces, water, and cleansing chemicals. Although the 



