118
Taking of smears.
The rat is laid on its back and nailed by its four feet to the table.
With a forceps pinch up a piece of the skin in the middle of the
abdomen, and out it with scissors, insert your scissors into the opening
thus made and cut the skin in the middle line right up the centre of
the belly, through the ribs up to the neck. Carry the incision into the
arm-pits for the examination of the axillary glands. Similarly at the
lower end carry the incision to each groin for the examination of the
femoral glands. Now pick up the liver with your forceps and carry it
well on to the chest : the stomach is thus freely exposed. Throw the
stomach in a similar manner on to the chest : this brings the spleen
into view lying on the posterior aspect of the stomach.
Clean a slide, pick up the spleen with a clean forceps and cut a piece
out of it and smear the slide with the cut surface of the spleen. The
slide is then labelled with the number of the rat and the number of the
division. Place the piece you have cut off into a flat dish containing
carbolic acid (1—20) or perchloride of mercury (1—1,000). These
dishes should be emptied into the incinerator. The pieces should on no
account be thrown on the table or replaced in the rat's abdomen. Stain
the smears with carbolic thionin for a few minutes, wash, allow to dry
and examine under 1/12 oil immersion lens.
Rat fleas,
It is probable that the infection of plague is conveyed to man from
an infected rat by the agency of the rat flea. "Whether the bacillus
undergoes some necessary evolutional development in the flea or is
conveyed mechanically is not at present known.
Fleas do not leave a dead rat for sometime after its death. To
• prevent infection spreading in this way the boiling water in the kerosine-
oil tin will be found effectual. The risk of infection also in the
dissecting room is thus to some extent mitigated.
Preparation and distribution of the bait.
The peons from the sectional offices should be requested to come to
the central office to assist in the preparation of the bait. Supply loaves,
flour and sugar according to the amount oí baits to be prepared. One
1/2 lb. loaf cut up in slices gives approximately 80 pieces of bait 1 inch
square ; and one 12 oz. tin of Common Sense Bat Exterminator will be
sufficient for 7 loaves of bread. If loaves are not procurable chappaties
(wheat, rice or raggi flour) or sliced plantain may be used. The poison
is spread according to the directions on the tin. The bread is cut into
slices, the poison is spread thinly over and covered with sugar and then
with flour to hide the poison. The slice is then cut up into pieces 1
inch square. The bait must not be handled and knives, forks and
spoons must be used in spreading, cutting and lifting the baits into the
poison basket.
The poison peon should go round his section in the evening and
distribute the bait, giving 5 or 6 pieces to each house in a piece of paper.
The poison is placed poison-side down in the corners of their rooms
behind furniture or in corners where the people keep their food chatties
and near rat holes. In cowsheds, etc., the bait is placed at the opening
of drains and near where the grain is stored.