INSTITUTE OF PUBLIC HEALTH, RANGOON, FOR THE YEAR 1936.

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to live in complete darkness. Crocidura fed on rice or bread and kept
in an ordinary lighted room died in a few days. This difficulty was,
however, overcome by feeding them with meat and keeping the cage in
a dark room.

          The experiment was carried out only after the C. Coerulea had been
kept alive under observation for at least a week and the indigenous
house rat (M. Concolor) was used as a control. In all, nine
C. Coeruleas were used. The technique adopted was as follows:—

          After keeping them under observation for seven days, they were
injected with one c.c. of a 48 hours broth culture of Pr. pestis. All
the nine control rats died within a period of four days. All the
C. coerulea remained healthy for several weeks except one which died
on the 9th day. The latter had an abscess at the site of injection.

          The above experiment indicates that C. Coerulea has some degree
of natural immunity against the plague baccilus. The next point that
has got to be considered is what role if any do these animals play in
the propagation of plague among human beings. Hirst in the year
1926-27 urged the preservation of these animals as they are enemies of
rats but the very fact that they appear to be immune to plague infection
weighs against Hirst's suggestion as they may play a part in acting as a
reservoir of plague infected fleas. Being a semi-domesticated animal,
they stand a good chance to come in contact with house rats
(M. Concolor) and should a fight ensue, a plague infected flea that
might have been harboured on the Crocidura may infest the Concolor
which could result in an epizootic among rats (rat fall).

          It is intended to prosecute further, this interesting and possibly
important enquiry.

III. Effect of Sulphur Fumigation on Vermin.

          The following experiment was done in this Institute to observe
the effect of sulphur fumigation on rats and vermin:—

Animals and insects used.

          The experiment was carried out on 24th July 1936 in the Plague
Laboratory which has a capacity of 5,302½ cubic feet. Every precau-
tion was taken to make the room perfectly air-tight. A total amount of
25 lbs. of sulphur was burnt. The floor of the room was sprinkled with
an adequate quantity of water and in addition several trays containing
water (totalling about 7 gallons) were placed on the floor as well as on
the working tables. Sulphur was ignited at 3 p.m. Samples of gas were
taken out and tested with the help of Clayton's gas-testing apparatus at
4 p.m. and 5 p.m. the concentration of SO₂ being 2 per cent and 2½ per
cent respectively. At 5 p.m. nothing was visible. inside the room. The