10
These remarks must not be construed as meaning that pucca "build-
ings are not preferable in every way to kutcha, but the provision of
pucca walls and floors is not in itself siifficient to ensure freedom from
rats.
Even in kutcha buildings something can be done towards eliminat-
ing the rat. The rat population of any place is directly determined
by the amount of food and shelter that such place affords. All
measures that lessen the amount of food and shelter for rats automati-
cally effect a reduction in the number of rats. Protection of stores of
food from the depredations of rats, and efficient scavenging, are thus
anti-plague measures of the first importance.
U,—PROTECTION OP THE BATS OF A COMMUNITY FROM PLAGUE.
Before embarking r on a detailed description of active rat-destruc-
tion measures it will be well to consider how best to protect the rat-
population of any town from becoming infected with plague or to
make the ever-present possibility of such an occurrence less likely.
To this end it is important to bear in mind the methods by which
plague-infection is conveyed from place to place.
1. G'rain and plague.—It is a common experience to find plague in
towns and villages beginning in the close vicinity of markets and grain
stores, and it is important to have a dear conception as to why this
should be so. As things are at present the rat population of any given
town or village is very much larger in the neighbourhood of markets
and grain stores than in other localities, with the result that when
plague is present the rat epizootic is likely to be more widespread in
such localities than elsewhere. It follows that grain exported from a
plague-infected town to another, goes from a part of the town of
despatch where plague is most severe, to a part of the receiving town
where the rat population is at a maximum. Not only so but grain and
similar merchandise offer facilities for the transport of rats which
baggage consisting of personal effects rarely affords. Plague-infected
rats are likely to be much more harmful as plague-infecting agents
than are fleas alone which, apart from their definitive hosts, a.ie short-
lived- especially if infective.
From these and other considerations it follows that the methods
of grain storage and grain transport are of paramount importance in
plague-infected and plague-threatened India, where the grain trade is
in a very special sense a ' dangerous trade,' and as such demands very
close supervision. There is a large mass of epidemiológica! evidence to
show that the rate of diffusion of pla.gue-infection is very slow when it
has to rely 011 the movements of the human population per se, but that
the movements of grain afford facilities for the dissemination of infection
equalled by no other agency. Were the grain stores of India kept
relatively rat-free a marked and rapid diminution of plague would most
assuredly result. Is such a consummation as impossible of attainment,,
or as difficult, as is usually assumed ?
A great deal can be done with no prohibitive outlay. In discuss»
ing this matter it is important to bear in mind certain facts regarding
the habits of rats cited above. They explain the logical basis of the
following desiderata of grain stores :-—
(ci) Wherever possible the wholesale storage of grain should bfi
effected in buildings apart from tliose in which retail trade is carried on,