causes there must always be present a primary cause, having a distinct
existence, capable of travelling from one part of the globe to another;
capable of spreading over any space however extended, or of confining
itself to any space however small—a district, a street, a house, a room.
Footnote 10:
See Baltimore case, p. 78.
It is urged that though we are unacquainted with the physical form or
chemical properties of this body, this is no reason why we should not
understand its force as a special agent in the production of disease,
just as we know the forces of other physical bodies, though not their
nature.
The existence of such a body being assumed, it is conceived that it
exists not in a gaseous but in a liquid state. It is supposed that it
cannot exist in a gaseous state because a gas is readily diffused and
dissipated; because when organic matter is reduced to a gaseous state,
it has passed from the organic into the inorganic kingdom, and there is
no evidence that the elementary bodies belonging to this kingdom are
capable of producing any form of fever; and because there is indubitable
evidence that organic matter in a recent state of putrescence—the more
recent the more potent—is capable of producing the most deadly forms of
fever. From these considerations it is conjectured that the primary
cause, whatever it be, is some subtle fluid which has not wholly lost
its organic composition, and that it consists of particles of extreme
minuteness, capable of attaching itself to the surfaces of other bodies,
and even of increasing under favourable circumstances.
It is further thought that this body is not equally diffused through the
atmosphere, but is only partially distributed, and that this accounts
for the local distribution of epidemics, and for their occasional
absence from places which apparently present all the conditions
favourable to their development.
Lastly, the opinion is gaining ground, that this body acts in the manner
of a ferment. It is urged in favour of this view, that a ferment being
an azotized substance in a state of putrefactive alteration, the body in
question must find, in the decomposing organic compounds with which
impure blood is charged, precisely the materials for taking on the
fermenting process. The advocates for this view think that the term
“_zymotic_” is not only the appropriate name of the whole of this class
of diseases, but that it also declares an interesting fact connected
with them. Whatever may be the truth with respect to these points, on
which at present we have no positive knowledge, one thing is certain,
that practically our concern is with the known causes,—the ascertained
conditions. These are palpable, definite, and capable of complete
removal and prevention.
Overcrowding, for example, we can prevent; the accumulation of filth in
towns and houses we can prevent; the supply of light, air, and water,
together with the several other appliances included in the
all-comprehensive word CLEANLINESS, we can secure. To the extent to
which it is in our power to do this, it is in our power to prevent
epidemics.
The human family have now lived together in communities more than six
thousand years, yet they have not learnt to make their habitations
clean. At last we are beginning to learn the lesson. When we shall have
mastered it, we shall have conquered epidemics. Our duties, then, and
our hopes in this respect, I shall proceed to show.
* * * * *
The principal constituents of the atmosphere maintain their equilibrium
steadily over the whole surface of the globe. There is scarcely any
difference in the relative proportion of its oxygen and nitrogen in the
torrid zone and in the arctic regions. Whatever influence the atmosphere
may have on climate must consequently depend on something adventitious
to it and not in anything forming a part of it. Possibly therefore that
something may be, in some degree, under human control.
The main constituents of climate are temperature and moisture, and these
are the climatic conditions that exercise the greatest influence on
epidemics.
Minor but still important conditions are the nature of the soil, the
proportion of land that is cleared and under cultivation, the extent of
forests, lakes, and rivers, the prevailing winds, the electrical state
of the atmosphere, and so on.
The temperature is highest where the sun’s rays are vertical, or nearly
so; where the sky is cloudless; where the day is longest; and where
there is the smallest difference between the fervid noon-tide heat and
the temperature of the short night.
The moisture is greatest where in addition to all the other sources of
humidity there are periodical rains. In the countries subject to these
rains, the entire extent of the level and low land is often covered a
foot deeper with water than before the rain set in.
Elevated temperature and excessive moisture are combined in tropical
countries; and they are concentrated in those parts of the tropics in
which there are extensive forests having an undergrowth of luxuriant
vegetation; in which the tides of the ocean penetrate deeply into the
interior of the land, and mix with the waters of the rivers; and in
which the rivers constantly overflow their banks and form marshes and
swamps.
In tropical countries there are tracts such as these that extend in
unbroken continuity hundreds of leagues. The western coast of Africa
(the Bight of Benin) presents an unbroken area of upwards of 100,000
square miles, consisting of one vast alluvial and densely-wooded forest,
irrigated by Atlantic tides, and intersected by numerous rivers and
creeks, whose muddy banks are constantly overflowed.
In describing a tropical forest, Humboldt says, “Under the bushy, deep,
green verdure of trees of stupendous height and size, there reigns
constantly a kind of half daylight, a sort of obscurity, of which our
forests of pines, oaks, and beech trees afford no example; forming a
carpet of verdure, the dark tint of which augments the splendour of the
aërial light.”
With this luxuriance of vegetation is combined a corresponding abundance
of animal life. The earth and air teem with living creatures.
“The mould,” observes the same distinguished traveller, “contains the
spoils of innumerable quantities of reptiles, worms, and insects.
Wherever the soil is turned up we are struck with a mass of organic
substances, which by turns are developed, transformed, and decomposed.
Nature in these climates appear more active, more fruitful, we might say
more prodigal of life.”
The air is still more alive than the land. Insects fill the lower strata
of the atmosphere to the height of fifteen or twenty feet, like a
condensed vapour. It is estimated that a cubic foot of air is often
peopled by a million of winged insects, which contain a caustic and
venomous liquid, several species being nearly two lines (1.8) long.
When two persons who have their home in these regions meet in the
morning, the first questions they address to each other are, “How did
you find the zancudoes during the night?” “How are we to-day for the
mosquitoes?” An ancient form of Chinese politeness, showing the ancient
state of that country, was—“Have you been incommoded in the night by
serpents?”
It appears that there are still inhabited places in which the Chinese
compliment on the serpents might be added to that of the mosquitoes.
Proportionate to this prodigality of organic life is the amount of
organic decomposition, the products of which are poured into the
atmosphere and suspended in the surrounding vapour and fog,[11] to which
they give a decided and often a highly offensive odour.
Footnote 11:
See note, p. 16.
“On fixing our eyes on the tops of the trees,” describes Humboldt, “we
discovered streams of vapour wherever a solar ray penetrated and
traversed the dense atmosphere, exhaling, together with the aromatic
odour yielded by the flowers, the fruit, and even the wood, that
peculiar odour which we perceive in autumn in foggy seasons. It might be
said, that notwithstanding the elevated temperature the air cannot
dissolve the quantity of water exhaled from the surface of the soil and
of the vegetation.”
“At the distance of several miles from the coast,” says Dr Daniell, in
describing the western shores of Africa, “the peculiar odour arising
from swampy exhalations and the decomposition of vegetable matter is
very perceptible, and sometimes even offensive. The water also is
frequently of a dusky hue, with leaves, branches, and other vegetable
debris floating on the surface, brought down from the interior by
innumerable narrow channels that empty their turbid streams into the
open ocean.”
It is under these climatic conditions that the worst forms of epidemics
are engendered: the most sudden in their attack, the most rapid in their
development, the most general in their prevalence, and the most mortal.
The form of the epidemic prevalent in any particular district is
dependent on the physical characters of the immediate neighbourhood.
Thus intermittents prevail chiefly in marshy and swampy districts:
remittents also chiefly there, though not exclusively; while in other
localities other forms arise approximating to the continued type of
temperate climates.
For the most part these epidemics are strictly endemic, and are confined
to the particular regions in which they are engendered. They never pass
the limit of the equatorial or tropical zone. Yellow Fever, one of the
most common and destructive of these diseases, is still more restricted
in its range, being confined within a definite line determined by
temperature. It is incapable of existing where the average range of the
thermometer is greater than from 76° to 86° of Fahrenheit, or where the
temperature varies more than from 5° to 10° night and day. Extreme heat
and moderate cold immediately stop it; nay, even the prevalence of a
cold wind for a few hours only.
In other instances these epidemics pass beyond the regions in which they
are produced, and sometimes extend to all the other quarters of the
globe. The Black Death, the range of which we have seen, was engendered
in China; the Cholera of our own day, generated in the delta of the
Ganges, the great source and centre of Indian epidemics, ravaged that
country long before it directed its course to Europe.
When these tropical epidemics advance into more temperate climes, they
lay aside nothing of their nature; they lose but little of their power.
Wherever they go they decimate the populations which they attack.
One remarkable peculiarity of some of these epidemics is, that natives
of the region in which they prevail are for the most part unsusceptible
to them. This is true however only of particular forms of pestilence.
Some of them acknowledge no acclimation. Cholera, for example, attacks
equally natives and new comers. On the other hand, yellow fever rarely
attacks the natives who reside permanently within its zone. Its chief
victims are strangers who have recently arrived within its sphere,
particularly the inhabitants of northern climates. The susceptibility to
its influence appears to be strictly proportionate to the degree of
northern latitude from which the stranger has arrived, and the shortness
of the interval that has passed since he left the European for the
Equatorial regions.
We see something of the same kind in the wide-spread epidemics of our
own country. During the prevalence of Cholera it was observed over and
over again, that persons coming directly from the pure air of the
country into the infected part of a town, were seized with the disease.
The explanation is not obvious. It would seem, however, to be connected
with the suddenness of the shock on the system. Priestley found, that
after shutting up a mouse in a given quantity of air a considerable
time, it seemed to be weak, and to be slowly dying. If at this period he
put a fresh mouse into the same air, it instantly died. It seems as if
the system can bear a pestiferous atmosphere better when gradually than
when suddenly exposed to it.
I do not know that I can give a more vivid picture of a tropical
epidemic than that which is afforded by the outbreak of Cholera in the
86th regiment at Kurrachee in June, 1846.
On this occasion the atmosphere was very peculiar,—damp, hot, stagnant,
and oppressive. Not a breath of air was stirring. A few isolated cases
of cholera had occurred for some days. The utmost alarm was excited in
the minds of experienced persons, who felt certain that an epidemic was
at hand. Their fears were too fully realized. On the night of the 15th,
upwards of 40 men were seized with cholera in its severest form; in two
days more 256 were attacked, of whom 131 were already dead.
“The floors of the hospital,” says Dr Thom, the surgeon of the regiment,
“were literally strewed with the livid bodies of men labouring under the
pangs of premature dissolution. Many were brought in with the cold and
clammy damp of death; as if sudden obstruction of every vital function
had taken place, and the fountains of life had been arrested by an
invisible but instantaneous shock. It was indeed a sight never to be
forgotten, to behold the powerful frames of the finest men of a fine
corps, who had that morning been in apparent good health, and most of
them on the evening parade, as if at once stricken down, and striving,
with the last efforts of gigantic strength, to resist a death-call that
would not be refused.”
In describing a river on the west coast of Africa, Dr Daniell says—“When
I visited it, I found two vessels moored a short distance from its
mouth, one of which within the space of five months had buried two
entire crews, a solitary person alone surviving. The other, which had
arrived at a much later period, had been similarly deprived of one-half
of its men, and the remainder were in such a debilitated condition as to
be incapable of undertaking any active or laborious duty. Immediately
before, another vessel had sailed from this port in such a deplorable
state as to be solely dependent on the aid of Kroomen to perform the
voyage.”
In the statistical report of Sir Alexander Tulloch it is stated, that
out of 1658 white troops sent out to military stations on the western
coast of Africa, 1271 perished from climatic diseases; while of the 387
who remained to be sent home, 17 died on their passage; 157 were
reported as incapable of further service; and 180 as qualified only for
garrison service; thus leaving only 33 out of 1658 men who were fit for
active service.
As we pass out of the torrid zone a remarkable change takes place in the
general character of epidemics. They lose more and more of their
intermittent type, and become either remittent or continued. The
remittent keeps its hold over the southern part of Europe, and
continually breaks out in the form of Yellow Fever. As we proceed
northward out of the yellow fever zone, that disease wholly disappears,
and typhus and its kindred maladies take its place; typhus commencing
precisely at the point where yellow fever ends.
There is, indeed, one of the ordinary diseases of temperate climes, and
only one, which appears capable of penetrating within the torrid zone,
and of committing greater ravages there than in lower temperatures, and
that is Small-pox. With this exception, the ordinary epidemics of
temperate climates do not enter the tropics, while, on the other hand,
the ordinary epidemics of the tropics every now and then decimate the
temperate regions.
“In these our latitudes,” says Dr William Fergusson, “cold and fatigue,
and sorrow and hunger, will generate fever anywhere; but every region,
every climate, will exhibit its own form of fever. With us it is Typhus;
in the warmer countries of Europe, Remittent; in the upper
Mediterranean, Plague; in the Antilles and Western Africa, Yellow Fever;
this last being restricted to particular localities, temperatures, and
elevation. While typhus fever goes out when you enter the tropics, it is
there that yellow fever commences; the pure epidemic of a hot climate
that cannot be transported or communicated upon any other ground.
Places, not persons, constitute the rule of its existence. Places, not
persons, comprehend the whole history, the etiology of the disease.
Places, not persons! Let the emphatic words be dinned into the ears of
the Lords of the Treasury, of Trade and Plantations, until they acquire
the force of a creed, which will save them hereafter from the absurdity
of enforcing a quarantine[12] in England against an amount of solar heat
of which its climate is insusceptible. Let them further be repeated in
the Schools of Medicine until the Professors become ashamed of imbuing
the minds of the young with prejudice and false belief, which, should
they ever visit warmer climates, may cause them to be eminently
mischievous in vexing the commerce and deeply and injuriously agitating
the public mind of whatever community may have received them.”
Footnote 12:
See Cases of the Eclair, Dygden, &c., _post._
Climate differs not only in different countries but in different parts
of the same country. The climate of the country is different from that
of the city. The climate of every city, town, and village, differs from
that of every other. The temperature, the moisture, and the other
meteorological conditions of different districts, nay, even of different
streets in the same town, vary to such a degree as to influence
materially their relative salubrity and the prevalence or absence of
particular classes of disease. These local climatic conditions and their
connection with prevalent diseases, have not as yet received due
attention: when they shall have received it—and they will receive it—a
new light will be shed on local epidemics.
* * * * *
I pass now to CIVILIZATION.
We have no sufficient knowledge of the state of the people and of their
diseases, in any of the civilized nations of antiquity, to trace the
relation between them. The authentic history of periods, comparatively
near to our own time, as far as concerns the diseases of the people,
goes scarcely further back than the 14th century. The first great
epidemic, to which I have so often called attention, occurred in that
century, and we have reliable evidence, both of the phenomena attending
this plague and the condition of the people at that time. I assume this
period therefore as my starting-point.
I take a civilized community to be one in which there exist—
1. A sovereign authority.
2. Laws incorruptibly administered.
3. Physical comfort generally diffused.
4. Intellectual development and activity generally diffused.
5. Recognition of the fundamental principles of religion and morality.
Without the two first, there can be no security for life and property,
both of which must be placed in absolute and unquestionable safety
before a single step can be taken out of the lowest depth of barbarism.
Without the two last, none of the others can be acquired. These
conditions are therefore the basis of the pyramid of society.
Taking these then as the essential constituents of civilization, and
applying them as a test to Great Britain, we shall see that at the
commencement of the 14th century England was in a state of barbarism,
since every one of these elements was wanting, although the foundation
of political and social institutions containing the germs of liberty and
progress had been already laid.
Practically, however, at that period there was no sovereign authority,
for the king had no sufficient power to maintain order, to protect the
rights and liberties of the people, or to defend his own throne against
armed men nominally his subjects; while the lord of every feudal castle
exercised a more perfect sovereignty over his vassals than the so-called
monarch over the nation.
Every town was a fortress, and every house in which it was safe to dwell
a castle, the inmates of which, like people in a garrison, constantly
held themselves prepared to resist attack, from which they were never
secure. They slept with arms at their side.
Marauders openly encamped on the public roads for the plunder of the
wayfarer, which often ended in his murder. Few persons ventured to
travel alone, and none without the reasonable apprehension that they
might never return alive.
Scarcely a third part of the area of the kingdom was under cultivation.
The remainder consisted of moor, forest, and fen. Vast tracts were under
water during the greater part of the year, and at other times formed
morasses, marshes, and swamps.
Immediately beyond the walls that encompassed the towns were large
stagnant ditches, which being the nearest receptacles for refuse, were
full of all sorts of decomposing filth.
The streets were narrow, unpaved, undrained, uncleansed, and unlighted.
There was no provision for the removal of the town refuse. Gutters were
formed at the sides of the streets, as in Bethnal Green and the
neglected parts of all our towns at the present time, into which the
inhabitants threw the refuse of their houses; forming in dry weather a
semi-fluid mass of corrupting animal and vegetable matter, and in rainy
weather black turbid rivulets which ultimately poured their contents
into some water-course.
The houses were mean and squalid, built of wood and wattles, thatched
with straw, without chimneys, the windows without glass, the floors
without boards, the furniture of the rudest description; the use of
linen was scarcely known; common straw formed the king’s bed. “The
floors,” says Erasmus, writing two centuries later, “generally are made
of nothing but loam, and are strewed with rushes, which being constantly
put on fresh, without a removal of the old, remain lying there, in some
cases for twenty years; with fish bones, broken victuals, the dregs of
tankards, and impregnated with other filth underneath, from dogs and
men.” Contemporary writers concur in representing the offensive odour of
decaying straw and rushes as universal in the houses.
There was no knowledge of the art of collecting, preserving, and storing
fodder. The animals for winter food were slaughtered in autumn, and
their flesh salted or smoked. It was only during three months of the
year, from Midsummer to Michaelmas, that any fresh animal food,
excepting game and river fish, was tasted even by the nobles of the
land. The common people subsisted chiefly on salted beef, veal, and
pork, the price of which was one-half less than that of wheat in the
time of Henry VIII.
There were no fresh vegetables. As late as the 18th century salads were
sent from Holland for the table of Queen Caroline. Sir John Pringle,
writing in the middle of the last century, states that his father’s
gardener told him that in the time of his grandfather cabbages were sold
for a crown a-piece. It was not until towards the close of the 16th
century (1585) that the potato was first brought to England, where it
was limited to the garden for at least a century and a half after it had
been planted by Sir Walter Raleigh in his own garden. It was first
cultivated as a field crop in Scotland so recently as the year 1752.
For many centuries England remained in the condition of country in which
no more subsistence is produced than is barely sufficient for the
necessities of the people. Consequently every year of scarcity became a
year of famine, and such years, about one in ten, occurred for ages with
great regularity, and often equalled in their terrible results the worst
famines of antiquity.