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causes are usually at work, as in the case of a grain godown customarily

used for the storage of grain brought from a place which is perennially

infected.

6. It is unfortunate that no accurate record exists for any town in

this Presidency of the genesis and history of the plague epidemics which

have afflicted it, nor has any special attention been directed to the loca-

lities and buildings in which the outbreaks began, or to the sources from

which infection has been imported. Yet these factors should be well

known to the local authorities, and should be the very foundation of

their preventive policy. Recent inquiries have, for example, elicited the

following facts :-

(a) Salem district is regularly infected from the Mysore State

through Hosur, and once plague appears in that town, it is a matter of

a few weeks or even days for it to make its appearance in Salem town

itself.

(b) In Coimbatore town, Uppilipalaiyam and the weavers' and

chucklers' quarters are well-known foci of infection from which plague

spreads year by year, and the town itself is periodically infected from

Mysore State or from South Kanara.

7. It is obvious that preventive measures which ignore fundamental

factors of the kind can have little practical value. It is a needless

extravagance, for instance, to attempt to destroy the rat population of

a whole town instead of concentrating effort on the localities where the

rat population is most dense, or where grain or cotton from areas

known to be infected is habitually stored. Until exact information is

on record for every town which is subject to epidemics, as to the foci

and channels of plague infection, the preventive staff is groping in the

dark.

8. The first duty of a health staff is therefore that of investigation.

To illustrate the kind of investigation needed, plague mortality figures

for the five towns, Bellary, Coimbatore, Salem, Mangalore   and

Vaniyambadi, have been collected for the twenty years, 1902-21, and

graphs have been prepared (attached to this memorandum), showing

the average monthly mortality in each. The first group demonstrates

the seasonal prevalence which plague exhibits everywhere. The second

group of graphs gives the actual deaths by months for the same period,

and illustrate the irregularity with which epidemics have appeared in

the towns in question. While perfect accuracy cannot be claimed for

the figures on which they are based, the graphs prove the need for

ascertaining why plague should break out in a given year and reappear

at irregular intervals of two, three or more years. There must be

some reasons for these irregularly occurring recrudescences and it is

only by intensive inquiry that the causes can be ascertained.

9. Experience proves that in towns and villages susceptible to

epidemics, infection usually spreads from grain dealers' stores, cloth

bazaars and petty shops which afford special facilities in the form of

food and shelter for the multiplication of rats. The first duty of a local

health authority is therefore to compile an accurate record of the

following points:-

(a) the location, method of construction of granaries for trade as

well as for household purposes, and their relation to the course of

epidemics,

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