Public, farmers', and wholesale markets, commission houses, and
similar places where vast quantities of foodstuffs are assembled and
redistributed are nearly always infested with large numbers of rats.
Such structures are usually concentrated in districts, and these often
become rat-breeding centers, from which the rats constantly overflow to
adjoining sections of the city. Rat proofing a district of this kind
would seem to be almost hopeless, yet it has often been demonstrated
that the task is not only feasible but entirely practicable. . Here,
more than anywhere else, the great need is the elimination of rat
shelters, which in turn means the free use of concrete or other
masonry. Scrupulous cleanliness is essential in markets, but even where
this is practiced it is not possible completely to eliminate rat food,
so the main reliance must be placed on the removal of all rat harbors.
Not only must the building in which the market is housed be rat
proofed, but also all the fixtures. In old public markets the stalls
were frequently constructed as if designed for the protection of rats.
Dark, out-of-the-way holes under counters, stands, and shelves afford
convenient places for the accumulation of trash, which it would be well
to destroy; and in such locations, with abundance of food at hand,
rats are in the best possible position to thrive and multiply. The
use of smooth concrete or tile counters (fig. 23) erected on concrete
floors deprive rats of the essential shelter, provided that the space
underneath the counter is kept clean and that stored material is moved
frequently. The smooth surface also prevents the rats from climbing and
makes it possible to leave edible products on the counter overnight
without fear of their being damaged or contaminated by the rodents. If
wooden floors are used, the boards should be laid flat on the concrete
or on sleepers not more than half an inch high.
[Illustration: B3137BM
Figure 23.--Rat proof market stalls. Rats are unable to climb the
smooth tiles to get at foodstuffs left on the counter]