142 HUMANE TREATMENT OF ANIMALS USED IN RESEARCH 
consideration should be given to the modernization of these 
facilities where needed. Institutional administrators frequently 
underestimate the cost of maintaining animals. Some may include 
only the initial procurement expense; and fail to take into 
account the true maintenance costs and depreciation expenses 
for cages and equipment. Supplemental grants made specifically 
for these purposes as well as for such items as resurfacing walls 
and ceilings, and improvement of ventilation and drainage systems 
would be prime investments. 
Section V - Equipment and Materials 
Metal is the most widely used material for the construc- 
tion of cages for animals (Table 11) . Ease and thoroughness of 
cleaning and maintenance as well as the length of useful life 
are the primary reasons for the use of metal cages. Stainless 
steel is a desirable metal for cage construction, not only for 
the aforementioned reasons, but also because of its high resis- 
tance to corrosion by animal discharges, detergents, solvents 
and cleaning compounds. Galvanized metal is the most commonly 
used metal. The high percentage figure for stainless steel 
mouse cages, given in Table 11, was strongly influenced by one 
private laboratory. 
The recent introduction of high impact plastics has 
made available small animal cages having the desirable features 
of metal cages and at a competitive cost. 
Approximately one-half of the institutions visited had 
post -operative recovery rooms for animals (47%) , cage washing 
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