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CHAPTER II.
VITAL STATISTICS.
Till near the end of the decennium 1901 to 1910 Salsette, for the purpose
of the compilation of vital statistics, was divided into the Thána Town Circle
and the Salsette Rural Circle. Since 1908 Bándra has been dealt with as a
separate Town Circle, and it has recently been decided to constitute Kurla as a
separate Town Circle from 1913. These separations of the urban from the rural
population of Salsette will enable variations in the intensity of such diseases as
Malaria, so much more a rural than an urban disease, to be more accurately
studied over a period of years in the future than they can be at present.
In 1911 Captain B. Higham, I, M. S., when acting as Deputy Sanitary
Commissioner, carried out for the Western Registration District the statistical
enquiry ordered in Government Resolution, General Department, No. 4796 of
29th September 1910. He prepared charts for two series of years before and
after the outbreak of Plague in the Presidency, showing curves for the mean
monthly figures for each táluka, of Total Births, Total Deaths, and Infantile
Mortality. He discontinued the plotting of curves for Still-births before he
came to the vital statistics of the Thána District, as he found that the curves for
different tálukas of the Násik District showed such a complete lack of con-
formity as to indicate that no reliance could be placed on the registration of Still-
births. He also prepared tables showing " epidemic figures," on the lines laid
down by Major Christophers. The compilations of Captain Higham, on which
his curves were prepared, have been of considerable assistance in preparing the
two charts that accompany this present report. Unfortunately, on account of the
destruction of certain records, he was not able to obtain his pre-Plague figures
for a decennium of continuous years. Apparently on account of some difficulty
in ascertaining the populations on which some of the ratios should be calculated
for this pre-Plague series of years, all the curves for the pre-Plague series, for
Births, for Total Deaths, and for Infant Mortality, are below the corresponding
ones for the post-Plague series. It was, accordingly, inadvisable to attempt to
draw conclusions based on the differences shown between the several kinds of
curves of the two series of years.
For the present report only the vital statistics of the intercensal decen-
nium 1901 to 1910 have been taken. The figures are for the whole of Salsette
Taluka,. including its urban populations.
THE DEATH-RATE.—A description of the Seasonal Chart (Chart
No. 1) is given on it. The principle followed in the preparation of the lowest
curve in it has been that rural registration work, at any rate, is generally accurate
as regards the total number of deaths, and that if the figures for certain diseases
which (1) tend to be seasonal in their incidence, (2) are easily recognized even
by ignorant persons and (3) are not themselves the sequelæ of Malaria, are
deducted from the total, the residue will give a fair idea of the seasonal variations
in mortality due to Malaria. A curve showing the death-rate among children
under one year, calculated, not on the population, but upon the births, has been
shown, both because this is the most accurate of all death-rates, and because it
affords a very good indication of variations in the intensity of Malaria, infants
being extremely susceptible to the disease. Letters and figures showing the
normal mean wind direction and steadiness for the day for each month of the
year at Colaba (Bombay) Observatory are given at the foot of the chart, as
also figures showing the mean monthly velocity of the wind in miles per hour
for the year 1911. The " steadiness " is the excess percentage of observations
in the direction of the monthly resultant.
It will be noticed that it is towards the end of the year that the Total
death-rate curve and what we may term, the curve of the Death-rate minus the
rate for Special Diseases most closely approach each other, i. e., it is then that
there is least of those diseases. Early in the year they begin to diverge, as Plague
begins to increase, and they remain widely apart for some months, their further
divergence from each other in April being due to the superaddition of Cholera
to Plague. The decline of Plague after April brings about a rapid fall in the
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