190 THE VIVARIUM. 
hinged to the front part of the frame which supports the zine 
bottom. This will act as a door to close the opening between the 
zinc bottom and the bottom of the case upon which the sheet- 
iron has been fastened. The door, which may be fastened below 
by means of a couple of buttons, is wseful for cleaning out the 
débris which from time to time must fall through the perforated 
zinc on to the floor of wood and sheet-iron below. The débris will 
chiefly consist of particles of dried feeces and bits of shed cuticle. 
A hinged door is made in one or both ends of the case, which will 
be very useful for cleansing purposes, and for the insertion of 
food and water. The bottom of the door or doors should be 
quite level with the perforated zinc floor. This latter arrange- 
ment is very convenient for sweeping out the interior of the 
Vivarium. The doors should be fastened by means of a small, 
strong spring-bolt—a bolt which always shoots into its socket 
when the door is closed. The particular bolt I am recommend- 
ing is made with a small ring-handle which lies flush with its 
' brass surroundings, and which withdraws the bolt from its 
socket when used to open the door. In addition to this bolt, 
each door should be fastened at the top and the bottom by a little 
button. 
In the centre of the roof of the case there ought to be another 
door, not less than 13ft. square, formed of perforated zinc. The 
door may be made in the following way: A strong frame of wood 
is constructed to exactly fit the square or oblong opening made in 
the top of the case, and over the outside or upper part of this 
frame is nailed a stout piece of perforated zinc—the zine extend- 
ing beyond the outside of the frame by at least 1din. This over- 
lapping of the zine will prevent the door from falling through 
into the case. The door is fastened by means of at least four 
wooden or metal buttons. This is the door which should be 
chiefly used in attending to the wants of the inmates of the 
Vivarium. The interior of the case ought to be quite smooth, and 
coloured according to the taste of the owner. The outside of the 
Vivarium, in order to prevent the loss of heat, should be covered 
with some thick felt of a pleasing colour, the felt being fastened 
in its place by strong drawing-pins ; for if it be glued on to the wood, 
there will be a difficulty in removing it should occasion require. 
