6
Total death-rate, which is not shared to any extent by the Infantile death-rate,
and a greater approximation of it to the Death-rate minus the rate for Special
Diseases. June is seen to be the all-round healthiest month. All the death-
rates rise after the monsoon has well set in. The rise is better marked in the case
of the Total death-rate than in that of the Death-rate minus that for Special
Diseases, and more marked still, and earlier marked, in the case of the Infantile
death-rate. Here Cholera, and Diarrhoea and Dysentery are in operation.
Their decline in September and October with the dying away of the monsoon,
and the approximation again of the two lower curves to one another, can be
seen at a glance.
Malaria not being a disease that kills very rapidly, though it is account-
able for so great a proportion of the deaths that do occur, it is not till the
Malaria season is well established that its effect on the mortality is marked.
In October there is slight rise in the Death-rate minus the rate for Special
Diseases, but in the case of the other two death-rates any rise due to commencing
mortality from Malaria is concealed by the fall in the mortality from diseases of
the bowel. But in November the rise is very evident in all the death-rates ;
and, at a time when, as seen by the maximum approximation of the two lower
curves on the chart to one another, there is less mortality from the Special
Diseases taken together than at any other time of year, Infantile mortality is
actually at its highest, because of the severity of Malaria at this season. In
infants Malaria kills much more quickly than in adults, and less often through
late complications, such as Pneumonia. This is probably the reason why the
infantile death-rate is already falling in December and January from, the
maximum in November, while the Death-rate minus the rate for Special Diseases
remains high, and actually reaches its maximum in January.
The continuous fall of this latter death-rate throughout the latter part of
the dry season affords the best indication of the continuous decline that goes on
then in the amount of Malaria. The curve for this death-rate certainly accords
with the account the cultivators themselves give of Malaria, that is essentially
a disease of the cold weather months, and that it is not till the warm weather
commences that the country begins to be healthy. It is with the fall of this
curve that the country residences of well-to-do Indians in Salsstte begin to be
occupied.
It will be noticed that it is in October that the wind is just changing
round to the North, from the West, before beginning to blow steadily from the
North in November, and that the reappearance of the Westerly element in March
synchronizes with the commencement of this steady fall in the mortality that
has been noted. This may be otherwise stated by saying that the absence of
the sea-breezes coincides in point of time with the greater mortality from
Malaria.
A description of the Yearly Chart for the intercensal decenniurn 1901 to
1911 (Chart No. 2) is given on it; it includes a curve for the variations in rain-
fall. The appearance of the curve showing the total Death-rate minus that for
Special Diseases does not suggest that the death-rate from Malaria has shown
any general tendency to increase during the decennium. Nor does it suggest
that there was any very severe epidemic visitation of the disease. But it does
show clearly two facts regarding the relation of Malaria to the rainfall that
have been noticed in other parts of India. One is that a mere heavy rainfall
does not of itself involve any necessary increase in the amount of Malaria. In
the year 1909 the rainfall was over 113", and in 1803 it was 127", yet no marked
rise in the amount of Malaria appears to have resulted in either case. The
other well-known fact illustrated by this chart is that what does cause a marked
rise in the incidence of Malaria is the occurrence of a year of defective rainfall
followed by one of ordinary or even of rather less than ordinary rainfall. The
most malarious year of the decennium was 1906, the rainfall for 1905 having
been so extraordinarily low, for Thána, as to be little over 58".
Hitherto variations in the incidence of Endemic Malaria have mainly
been studied; it remains to be seen whether the figures do or do not give an
indication of the occurrence of waves of Epidemic Malaria, such as have been