H—3l

In Fig. IV, persons ill in the test areas are indicated by the black bars, those in the control areas being uncoloured. The situation before Ist November is shown in the upper half of the diagram, that after Ist November in the lower half. The following inferences may be drawn: —

Fig. IV.—Illnesses Amongst Equal Populations (1,091 Each) Visited in December, 1947

(а) Before Ist November suggestive illnesses of long duration were practically identical in the two areas studied, both in frequency and severity. (б) Suggestive illnesses of short duration were nearly twice as common in the test areas as in the control areas (I*B :1).

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