At the recent meteorological conference held at the Health Exhibition, Dr.
J.W. Tripe read a paper of much interest on some relations of
meteorological phenomena to health.
In ages long past these relations excited much attention, but the
knowledge concerning them was of the vaguest kind; and indeed, even now,
no very great advance has been made, because it is only quite recently
that we have been able to compare a fairly accurate record of deaths with
observations taken at a number of reliable meteorological stations. The
more useful and searching comparison between cases of sickness, instead of
deaths, and meteorological phenomena has yet to be accomplished on a large
scale in this country, and especially as regards zymotic diseases. In
Belgium there is a Society of Medical Practitioners, embracing nearly the
whole country, that publishes a monthly record of cases of sickness, of
deaths, and of meteorological observations; but the only attempt on a
large scale in this country, which was started by the Society of Medical
Officers of Health for the whole of London, failed partly from want of
funds, and partly from irregularity in the returns. My remarks, which must
necessarily be very brief, will refer to the relations between (1)
meteorological phenomena and the bodily functions of man, and (2) between
varying meteorological conditions and death-rates from certain diseases.
As regards the first, I will commence with a few brief remarks on the
effects of varying barometric pressures. A great deal too much attention
is paid to the barometer if we regard it as indicating only, as it really
does, variations in the weight of the column of air pressing upon our
bodies, because, except at considerable elevations, where the barometer is
always much lower than at sea level, these variations produce but little
effect on health. At considerable elevations the diminished pressure
frequently causes a great feeling of malaise, giddiness, loss of strength,
palpitation, and even nausea; and at greater heights, as was noticed by
Mr. Glaisher in a very lofty balloon ascent, loss of sight, feeling, and
consciousness. These were caused by a want of a sufficient supply of
oxygen to remove effete matters from the system, and to carry on the
organic functions necessary for the maintenance of life. On elevated
mountain plateaus, or even in high residences among the Alps, an increased
rapidity in the number of respirations and of the pulse, as well as
increased evaporation from the lungs and skin, occur.
For some years past, many persons suffering from consumption, gout,
rheumatism, and anæmic affections have gone to mountain stations, chiefly
in Switzerland, for relief, and many have derived much benefit from the
change. It must not, however, be supposed that diminished atmospheric
pressure was the chief cause of the improvement in health, as its
concomitants, viz., a diminution in the quantity of oxygen and moisture
contained in each cubic foot of air, probably the low temperature, with a
total change in the daily habits of life, have assisted in the beneficial
results. The diminution in the quantity of air, and consequently of
oxygen, taken in at each breath is to a certain extent counterbalanced by
an increased frequency and depth of the respirations, and a greater
capacity of the chest. In this country, alterations in the barometric
pressure are chiefly valuable as indicating an approaching change in the
wind, and as well as of the amount of moisture in the air; hence the
instrument is often called "the weather glass." A sudden diminution in the
atmospheric pressure is likely to be attended with an escape of ground air
from the soil, and therefore to cause injury to health, especially among
the occupants of basement rooms, unless the whole interior of the building
be covered with concrete.
_Temperature._--Experience has shown that man can bear greater variations
of temperature than any other animal, as in the Arctic regions a
temperature of -70 degrees Fahrenheit, or more than 100 degrees below
freezing point, can be safely borne; that he can not only live but work,
and remain in good health, in these regions provided that he be supplied
with suitable clothing and plenty of proper food. On the other hand, man
has existed and taken exercise in the interior of Australia when the
thermometer showed a temperature of 120 degrees Fahrenheit, or nearly 90
degrees above freezing point, so that he can live and be in fairly good
health within a range of nearly 200 degrees Fahrenheit.
The effects of a high temperature vary very much according to the amount
of moisture in the air, as when the air is nearly saturated in hot
climates, or even in summer in our own, more or less languor and malaise
are felt, with great indisposition to bodily labor. With a dry air these
are not so noticeable. The cause is evident; in the former case but little
evaporation occurs from the skin, and the normal amount of moisture is not
given off from the lungs, so that the body is not cooled down to such an
extent as by dry air. Sunstroke is probably the result, not only of the
direct action of the sun's rays, but partly from diminished cooling of the
blood by want of evaporation from the lungs and skin.
The effects of temperature on man do not depend so much on the mean for
the day, month, or year, as on the extremes, as, when the days are hot and
the nights comparatively cool, the energy of the system becomes partially
restored, so that a residence near the sea, or in the vicinity of high
mountains, in hot climates is, other things being equal, less enervating
than in the plains, as the night air is generally cooler. It is commonly
believed that hot climates are _necessarily_ injurious to Europeans, by
causing frequent liver derangements and diseases, dysentery, cholera, and
fevers. This, however, is, to a certain extent, a mistake, as the recent
medical statistical returns of our army in India show that in the new
barracks, with more careful supervision as regards diet and clothing, the
sickness and death-rates are much reduced. Planters and others, who ride
about a good deal, as a rule keep in fairly good health; but the children
of Europeans certainly degenerate, and after two or three generations die
out, unless they intermarry with natives, and make frequent visits to
colder climates. This fact shows that hot climates, probably by
interfering with the due performance of the various processes concerned in
the formation and destruction of the bodily tissues, eventually sap the
foundations of life among Europeans; but how far this result has been
caused by bad habits as regards food, exercise, and self-indulgence, I
cannot say. Rapid changes of temperature in this country are often very
injurious to the young and old, causing diarrhoea and derangements of the
liver when great heat occurs, and inflammatory diseases of the lungs,
colds, etc., when the air becomes suddenly colder, even in summer.
The _direct_ influence of rain on man is not very marked in this country,
except by giving moisture to the air by evaporation from the ground and
from vegetable life, and by altering the level of ground water. This is a
subject almost overlooked by the public, and it is therefore as well that
it should be known that when ground water has a level persistently less
than five feet from the surface of the soil, the locality is usually
unhealthy, and should not, if possible, be selected for a residence.
Fluctuations in the level of ground water, especially if great and sudden,
generally cause ill-health among the residents. Thus, Dr. Buchanan in his
reports to the Privy Council in 1866-1867, showed that consumption (using
the word in its most extended sense) is more prevalent in damp than on dry
soils, and numerous reports of medical officers of health, and others,
which have been published since then, show that an effective drainage of
the land, and consequent carrying away of the ground water, has been
followed by a diminution of these diseases.
Varying amounts of moisture in the air materially affect the health and
comfort of man. In this country, however, it is not only the absolute but
the relative proportions of aerial moisture which materially influence
mankind. The quantity of aqueous vapor that a cubic foot of air can hold
in suspension, when it is saturated, varies very much with the
temperature. Thus at 40 degrees Fahr. it will hold 2.86 grains of water;
at 50 degrees, 4.10 grains; at 60 degrees, 5.77 grains; at 70 degrees,
8.01 grains; and at 90 degrees as much as 14.85 grains. If saturation be
represented by 100, more rapid evaporation from the skin will take place
at 70 degrees, and 75 per cent. of saturation, than at 60 degrees when
saturated, although the absolute quantity of moisture in the air is
greater at the first named temperature than at the latter. As regards the
lungs, however, the case is different, as the air breathed out is, if the
respirations be regular and fairly deep, completely saturated with
moisture at the temperature of the body. In cold climates the amount of
moisture and of the effete matters given off from the lungs in the expired
air is much greater than in hot climates, and the body is also cooled by
the evaporation of water in the form of aqueous vapor. Moist air is a
better conductor of heat than dry air, which accounts for much of the
discomfort felt in winter when a thaw takes place as compared with the
feeling of elasticity when the air is dry. In cold weather, therefore,
moist air cools down the skin and lungs more rapidly than dry air, and
colds consequently result. London fogs are injurious, not only on account
of the various vapors given off by the combustion of coal, but in
consequence of the air being in winter generally saturated with moisture
at a low temperature. The injuriousness of fogs and low temperatures will
be presently dwelt upon at greater length.
Variations in the pressure and temperature of the atmosphere exert a
considerable influence on the circulation of air contained in the soil,
which is called ground air. As all the interstices of the ground are
filled with air or water, the more porous the soil, the greater is the
bulk of air. The quantity of air contained in soil varies very much
according to the material of which the soil is composed, as it is evident
that in a gravelly or sandy soil it must be greater than when the ground
consists of loam or clay. The estimates vary from 3 to 30 per cent., but
the latter is probably too high. If, therefore, a cesspool leak into the
ground, the offensive effluvia, if in large quantities, will escape into
the soil, and are given off at the surface of the ground, or are drawn
into a house by the fire; but, if small, they are rendered innocuous by
oxidation. The distance to which injurious gases and suspended or
dissolved organic matters may travel through a porous soil is sometimes
considerable, as I have known it pass for 130 feet along a disused drain,
and above 30 feet through loose soil.
Winds exercise a great effect on health both directly and indirectly.
Directly, by promoting evaporation from the skin, and abstracting heat
from the body in proportion to their dryness and rapidity of motion. Their
indirect action is more important, as the temperature and pressure of the
air depend to a great extent on their direction. Thus winds from the north
in this country are usually concomitant with a high barometer and dry
weather; in summer with a pleasant feeling, but in winter with much cold.
Southwest winds are the most frequent here of any, as about 24 per cent.
of the winds come from this quarter against 16½ from the west, 11½ from
the east, and the same from the northeast; 10½ from the south, 8 from the
north, and a smaller number from the other quarters. Southwest winds are
also those which are most frequently accompanied 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 14½,
and northeast 11½ 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° F. was adverse to the spread of this disease, that the
greatest relative decrease took place when the mean temperature was below
40°, and that the greatest number of deaths occurred in the months having
a mean temperature of between 45° and 57° 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° F. in the
second week to 36.2° 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 and in
December of the same year there was a rapid fall of temperature, when the
number of deaths from acute diseases of the lungs rose from 297 to 358,
350, 387, 541, 553, and 389 in the respective weeks. From November 29 to
December 9 the sun was seen only on two days for 4½ hours, and from
December 9 to the 18th also on two other days for less than 4 hours,
making the total amount of sunshine 8.1 hours only in 20 days. In January
and February the excess of weekly mortality from all diseases reached the
large number of 504 deaths; in December it was less, the fogs not having
been so dense, but the excess equaled 246 deaths per week.
The relations between a high summer temperature and excessive mortality
from diarrhoea have long been well known, but the immediate cause of the
disease as an epidemic is not known. Summer diarrhoea prevails to a greater
extent in certain localities, notably in Leicester (and has done so for
years); and the cause has been carefully sought for, but has not been
found out. Recent researches, however, point to a kind of bacillus as the
immediate cause, as it has been found in the air of water-closets, in the
traps under the pans, and in the discharges from infants and young
children. In order to indicate more readily how intimately the mortality
from diarrhoea depends on temperature, I now lay before you a table showing
the mean temperature for ten weeks in summer, of seven cold and hot
summers, the temperature of Thames water, and the death-rates of infants
under one year per million population of London:
_London.--Deaths under 1 Year, in July, August, and part of
September, from Diarrhoea per 1,000,000 Population Living
at all Ages, arranged in the Order of Mortality._
Age 0-1 year.
Mean Temperature Deaths from Diarrhoea
Years. temperature, of Thames per 1,000,000
10 weeks. water. population living at
all ages.
1860 58.1° 60.6° 151
1862 59.0 62.0 189
1879 58.7 60.7 228
1877 61.2 63.3 347
1874 61.7 63.8 447
1878 63.7 64.1 576
1876 64.4 64.9 643
As may be seen, the deaths of infants under 1 year of age from diarrhoea
per 1,000,000 population was only 151; while the mean summer temperature
was only 58.1° F. against 189 in 1862, when the mean temperature was
59.0°. In 1879, when the mean temperature was 58.7°, the deaths from
diarrhoea rose to 228 per million, but a few days were unusually hot. In
1877 the mean temperature of the air was 61.2°, of the Thames water 63.3°,
and the mortality of infants from diarrhoea 347 per million population. In
1874, when the mean temperature of the air was 61.7°, the mortality rose
to 447 per million; and in the hot summers of 1878 and 1876, when the mean
air temperatures were 64.1° and 64.9° respectively, the death-rates of
infants were 576 and 642 per million population. The relations, therefore,
between a high summer temperature and the mortality from diarrhoea in
infants are very intimate. I have selected the mortality among infants in
preference to that at all ages, as the deaths occur more quickly, and
because young children suffer in greater proportion than other persons.
The proportionate number of deaths at _all ages_ from diarrhoea corresponds
pretty closely with those of infants. To prove this, I made calculations
for three years, and ascertained that only 3.9 per cent. of all the deaths
from this disease were registered in the weeks having a temperature of
less than 50°; 11.9 per cent. in the weeks having a temperature between
50° and 60°; while in the comparatively few weeks in which the temperature
exceeded 60° F., as many as 84.2 per cent. of the total number of deaths
was registered. In the sixteen years, 1840-56, for which many years ago I
made a special inquiry, only 18.9 per cent. of all the deaths from
diarrhoea occurred in winter and spring, against 81.1 per cent. in summer
and autumn. In the twenty years, 1860-79, there were seven years in which
the summer temperature was in defect when the mortality per 100,000
inhabitants of London was 200; while in ten summers, during which the
temperature was in excess by 2° or less, the mortality was 317 per
100,000. The mean temperature was largely in excess, that is to say, more
than 2° plus in three of these summers, when the mortality reached 339 per
100,000 inhabitants.
These figures show that great care should be taken in hot weather to
prevent diarrhoea, especially among young children; by frequent washing
with soap and water to insure cleanliness, and proper action of the skin;
by great attention to the food, especially of infants fed from the bottle;
free ventilation of living rooms, and especially of bedrooms; and by
protection, as far as possible, being afforded from a hot sun, as well as
by avoiding excessive exercise. All animal and vegetable matter should be
removed from the vicinity of dwelling-houses as quickly as possible
(indeed, these should be burnt instead of being put in the dust-bin), the
drains should be frequently disinfected and well flushed out, especially
when the mean daily temperature of the air is above 60° F.
Time will not admit of more than a mere mention of the relations between
meteorological phenomena and the mortality from many other diseases and
affections, such as apoplexy from heat, sunstroke, liver diseases, yellow
fever, cholera, whooping-cough, measles, etc., especially as the state of
our knowledge on the subject is so very limited. A comparison between the
mortality from several diseases in this and other countries shows that
certain of these do not prevail under closely corresponding conditions.
Thus the curves of mortality from whooping-cough, typhoid fever, and
scarlet fever do not correspond with the curves of temperature in both
London and New York, and the same may be said of diarrhoea in India. It is
therefore evident that some other cause or causes than a varying
temperature must be concerned in the production of an increased death-rate
from these diseases. The subject is of great importance, and I do not
despair of our obtaining some day a knowledge of the agents through which
meteorological phenomena act in the production of increased and decreased
death rates from certain diseases, and the means by which, to a certain
extent, these injurious effects on man may be presented.
* * * * *
P. Rosenbach has found experimentally that potassium bromide diminishes
the sensibility of the cortical substance of the cerebrum to electric
excitement, while, the excitability of the underlying white substance
remains unaltered.
* * * * *