Equipment 385 
the coldness of the material. As sometimes constructed, 
they are also slippery, but this need not be the case, 
as a rough finish will obviate this difficulty. The coldness 
may be avoided either by the liberal use of bedding or 
by an overlay, which consists of a board platform laid over 
that part of the cement floor on which the pigs are to 
lie and the bedding placed on top of this. In summer, of 
course, this platform should be removed and the pigs 
allowed to lie on the cool floor. Some persons have 
recommended two layers of coal tar between the grouting 
and surface layers of cement. In winter, moisture some- 
times accumulates under the platform, so that it will 
need to be moved from time to time, but if the dust is 
kept from beneath it, very little dampness will accumulate. 
Those who have used concrete floors differ in their judg- 
ment on them. Some maintain that the pigs warm the 
concrete floor through their bedding, and the floors re- 
main warm, provided they are dry. On the other hand, 
others maintain that the floors are always cold and clammy, 
and must make the pigs uncomfortable. Undoubtedly 
the drainage and ventilation of the building have much 
to do with the condition of the concrete floor. If the 
ventilation is not good, more moisture will accumulate 
on the floors; and if drainage is poor, they will like- 
wise be damp. If ventilation and drainage are good, 
however, keeping the floors dry is a much easier problem, 
especially if the floors are thoroughly water-proof, which 
will not be the case unless the concrete is made from the 
correct mixture and properly tamped. 
DIPPING VAT 
In order to keep pigs free from external vermin and 
occasional. attacks of mange, some system of dipping is 
2c 
