ed by rain, as about 30 per
cent. of the rainy days are coincident with southwest winds. Another set
of observations give precisely the same order, but a considerable
difference in their prevalence, viz., southwest 31 per cent., west 141/2,
and northeast 111/2 per cent. Easterly winds are the most unpleasant, as
well as the most injurious to man of all that occur in this country.

I now propose discussing very briefly the known relations between
meteorological phenomena and disease. I say the known relations, because
it is evident that there are many unknown relations of which at present we
have had the merest glimpse. For instance, small-pox, while of an ordinary
type, and producing only a comparatively small proportion of deaths to
those attacked, will sometimes suddenly assume an epidemic form, and
spread with great rapidity at a time of year and under the meteorological
conditions when it usually declines in frequency. There are, however, in
this country known relations between the temperature and, I may say,
almost all diseases. As far back as 1847 I began a series of elaborate
investigations on the mortality from scarlet fever at different periods of
the year, and the relations between this disease and the heat, moisture,
and electricity of the air. I then showed that a mean monthly temperature
below 44.6 deg. F. was adverse to the spread of this disease, that the
greatest relative decrease took place when the mean temperature was below
40 deg., and that the greatest number of deaths occurred in the months having
a mean temperature of between 45 deg. and 57 deg. F. Diseases of the lungs,
excluding consumption, are fatal in proportion to the lowness of the
temperature and the presence of excess of moisture and fog. Thus, in
January, 1882, the mean weekly temperature fell from 43.9 deg. F. in the
second week to 36.2 deg. in the third, with fog and mist. The number of deaths
registered in London during the third week, which may be taken as
corresponding with the meteorological conditions of the second week, was
1,700, and in the next week 1,971. Unusual cold, with frequent fogs and
little sunshine, continued for four weeks, the weekly number of deaths
rising from 1,700 to 1,971, 2,023, 2,632, and 2,188. The deaths from
acute diseases of the lungs in these weeks were respectively 279, 481,
566, 881, and 689, showing that a large proportion of the excessive
mortality was caused by these diseases. At the end of November a