while any of the factors invoked may suffice to produce the catarrhal
(sporadic) form, none will explain the specific (epidemic) form of the
disease; both forms may be alike in their lesion and signs, but they
differ widely in their cause. In other words, dysentery is only a
clinical, and is in no way an etiological, expression of a disease. In
this respect dysentery finds its analogue in a much grosser lesion of
the bowels--namely, occlusion, acute or chronic, which, while it
presents pretty much the same train of symptoms, may depend upon a
great variety of causes, as impaction, strangulation, intussusception,
etc. While any of the causes cited may be sufficient to excite the
catarrhal form of the disease, the same causes may stand to the
specific form only in the relation of predisposing agents. Or, as
Maclean has better put it, "It appears that many of the so-called
causes of dysentery must be regarded more as acute agents of
propagation than of causation."
As a secondary disease dysentery occurs in the course of, or as a
sequel to (not infrequently as the terminal affection of), pyæmia and
septicæmia (puerperal fever), typhus and typhoid fevers, pneumonia,
Bright's disease, variola, scarlatina, abscess of the liver (though the
order of sequence is here oftener reversed), scorbutus, marasmus from
any cause, tuberculosis, and cancer. It must not be forgotten, however,
of these latter affections that each produces its own lesions in the
large intestine, which are not to be confounded with those of genuine
dysentery.
The view that dysentery shows a periodicity of recurrence at certain
distinct intervals or cycles--three, five, or ten years--is entirely
without foundation in fact; but there is strong ground for believing
that the disease is gradually abating both in frequency and virulence
with improvements in sanitation and hygiene. Thus, Heberden shows that
the {785} number of deaths set down in the seventeenth century under
the titles of bloody flux and gripings of the guts was never less than
1000 annually, and in some years exceeded 4000, whereas during the last
century the number gradually dwindled down to 20 (Watson)--a number
which is certainly a misprint for 200; and Aitken states that as a
cause of death it has been decreasing since 1852. Geissler also
remarks[1] that the variation in epidemics is nowhere so well
illustrated as in the case of dysentery. A noticeable reduction in the
number of cases in England began about 1850, and has continued almost
without interruption to the present time, so that now (1880) six to
eight times less cases occur than in the forties. The same diminution
has been noticed in Bavaria and Sweden. In Sweden the cases treated by
physicians in 1857 numbered no less than 37,000, with over 10,000
deaths; whereas now the number is reduced to 400-500 a year, and the
mortality has experienced a corresponding reduction from 20-30 to 6-8
per cent.
[Footnote 1: _Periodische Schwanderungen der wichtigsten Krankheiten_.]
At the same time, it is known of dysentery that it sometimes shows an
almost freakish recurrence after long intervals of time, appearing in a
place for many decades free from the disease, to establish itself there
for years as a regular endemic malady, not to disappear again for a
long series of years; in which respect, Hirsch remarks, it much
resembles malaria.
Allusion has been already made to the occasional curious
circumscription of the disease in definite localities. In fact,
dysentery, even when late to assume the proportions of a widespread
epidemic, begins, as a rule, and is confined for a time, in individual
enclosed regions--prisons, barracks, hospitals, etc.; and in the
process of dissemination it is rather characteristic of the disease to
leap over or to spare intervening territory and appear in new foci at
some distance from its original seat. A direct irradiation or linear
transmission of the disease is the exception, and not the rule. The
significance of this fact will become evident in the study of the
etiology of the disease.
Dysentery is pre-eminently a disease of army life, its victims among
soldiers numbering more than all other diseases together. Sir James
MacGrigor, Medical Superintendent of the British army, called it the
scourge of armies and the most fatal of all their diseases. Aitken says
that "it has followed the tracks of all the great armies which have
traversed Europe during the continental wars of the past two hundred
years." It decimated the French, Prussian, and Austrian armies in 1792.
In Cape Colony in 1804 every fourth man among the soldiers was attacked
with the disease, and of those attacked every fifth man died. In
Napoleon's campaign in Egypt dysentery numbered one-half more victims
than the plague; Kinglake says that 5000 men died of dysentery alone in
the war of the Crimea; and in our own country during our Civil War from
1861-65 chronic camp dysentery was the cause of more than one-fourth of
all the diseases reported, the mortality being at the rate of 12.36 per
1000.
Woodward relates that the dysenteries, acute and chronic, with
diarrhoeas, made their appearance in the new regiments at the beginning
of the war, and, though mild at first, quickly assumed a formidable
character. "Soon no army could move without leaving behind it a host of
the victims. They crowded the ambulance-trains, the railroad-cars, the
{786} steamboats. In the general hospitals they were often more
numerous than the sick from all other diseases, and rivalled the
wounded in multitude. They abounded in the convalescent camps, and
formed a large proportion of those discharged for disability." Most of
the prisoners died of this disease, and great numbers succumbed to it
on retirement to their homes after the cessation of the war. It is the
story of many a campaign, Eichhorst says, that dysentery kills more men
than the enemy's guns.
The fact that it sometimes shows itself in periodic form or with
periodic exacerbation, that it is sometimes successfully treated with
quinia, and that, as has been noticed from the days of Hippocrates
down, it prevails in greatest intensity in malarial regions, has given
rise to the view that dysentery is a malarial disease. This view, which
was strongly advocated by many of the older writers, Senac, Fournier,
Annesley, met with renewed support at the hands of many of the surgeons
in our Civil War. But wider observation has shown the fallacy of such a
view; for not only may the diseases prevail entirely independently of
each other in malarial regions, but there are regions where one does
and the other does not exist. Thus Huebner quotes from Rollo concerning
St. Lucie (West Indies), a town situated on a mountain in the midst of
a swampy country in which both dysentery and malaria abound, while the
town itself is almost free from dysentery; and Dutrolan cites Réunion
as a place where marsh fevers do not occur, while dysentery is very
common. Bérenger-Féraud[2] scouts the idea of any such connection. "Let
us mention only St. Pierre de la Martinique," he says, "where there is
not a piece of marsh as big as a hand, but where dysentery has made
great ravage more than once. We might cite also Mauritius, Gibraltar,
Malta, New Caledonia--places exempt, or almost exempt, from malaria,
but often visited by dysentery."
[Footnote 2: _Traité théorique et clinique de la Dysenterie, etc._,
Paris, 1883.]
The view that dysentery is a form of typhus or typhoid fever
(Eisenmann) or scurvy needs no refutation in the light of existing
knowledge regarding the pathogenesis and pathology of these affections.
These diseases may often complicate, but can never cause, dysentery.
Dysentery is a disease which spares no age, sex, or social condition,
the seeming greater suffering of the poorer classes being due to the
filth, food, darkness, dampness--in short, to the bad sanitation--of
poverty.
Though the disease is often confined exclusively to soldiers in the
midst of a civil population, examples are not wanting of an exclusive
selection of civilians or of an indiscriminate attack in every
direction. Lastly, dysentery is a disease which may recur repeatedly in
the same individual, one attack rather predisposing to than preventing
another.
ETIOLOGY.--Dysentery is an omnipresent disease. "Wherever man is,"
Ayres observed of it nearly a quarter of a century ago, "there will
some of its forms appear." But the character of the form, and more
especially the extent and severity of the disease, vary in extreme
degree with the conditions surrounding the abode of man. No one of
these conditions affects the disease so markedly as the climate. It is
the testimony of Hirsch, based upon the study of seven hundred
epidemics of the disease, that no other disease is so dependent upon
the influence of the climate. The home of dysentery is the tropical
zone. It prevails in greatest frequency {787} and virulence in the
tropics, and in those regions of the tropics where the characteristics
of this zone are more pronounced, diminishes in intensity in the
temperate regions, and occurs only in sporadic form farther north. At
40° latitude the line may be pretty sharply drawn; beyond it dysentery
as an epidemic is almost unknown.[3]
[Footnote 3: Shakespeare (_Troilus and Cressida_) cites "griping of the
guts" among the "rotten diseases of the south."]
India has been from time immemorial the hotbed of this disease.
Henderson says it is perhaps more fatal to natives than all other
diseases put together, and Hutchinson, Hunter, and Tytler observe that
it causes three-fourths of the deaths among the natives of Hindostan.
In Egypt the disease is indigenous, and is, according to Frank, post
pestem maxime timendus. Greisinger reports that one-half of all the
autopsies made by him in Egypt showed dysentery as a primary or
secondary affection. It is epidemic here at all times, Roser says, and
all fatal cases of acute or chronic disease finally perish with it.
Similar testimony might be adduced from a large part of Africa, much of
Asia, the Indian Archipelago, and the West Indies. It rages
"murderously" in Peru, causing a mortality in some epidemics of 60 to
80 per cent., and occurs in this country not only in the valleys, but
in cities and provinces at the lofty elevation of 8000 to 13,000 feet.
Heat, moisture, vegetable decomposition, and sudden atmospheric change
are the distinguishing characteristics of southern climes, and the
study of the etiology of a disease incident or indigenous to these
conditions calls for an investigation of these various factors.
It is well established of dysentery that it occurs for the most part in
the hottest season of the year. Of 546 epidemics tabulated by Hirsch,
404 prevailed in summer and fall, 113 in fall and winter, 16 in spring
and summer, and only 13 in winter. Fourteen-fifteenths of the whole
number of epidemics occurred in the months of June to September. And it
is corroborative of these conclusions that of 1500 deaths from
dysentery in the cities of Boston, New York, Philadelphia, and
Baltimore from 1816 to 1827, 1100 occurred in the months of July,
August, and September. In fact, the Census Reports (1860-70) of our
country show the maximum mortality in August and September, and the
minimum in January and February.
The prevalence of unusual heat may also call out an epidemic in places
where the disease usually shows itself only in endemic or sporadic
form. Thus, the severe epidemic of 1540 in England was preceded by a
heat so intense as to dry up the wells and small streams, in
consequence of which many cattle died of thirst; and the epidemics of
1583 in Germany, of 1758 in France, and of 1847 in our own country,
were characterized in the same way. Interesting in this connection is
the statement of Frick concerning the epidemic in Baltimore in 1849,
who found the cases to increase and decrease almost in proportion to
the elevation and depression of temperature. The epidemic of Weimar in
1868, where 12,000 people fell ill with the disease, illustrated the
rule when it ceased suddenly on the approach of cool weather at the end
of August.
But that heat alone is not sufficient to account for the genesis of the
disease is apparent from the occasional occurrence of it in the tropics
in the colder seasons of the year; in the colder climates, Russia,
Sweden, {788} and Canada; and in temperate regions during exceptionally
cool seasons, as in Plymouth in 1769, London in 1808, Massachusetts in
1817. Moreover, the temperate zone is often characterized by seasons of
unusual heat, during the prevalence of which dysentery may be almost
unknown. Thus, during the summer of 1881, in Cincinnati, the
thermometer scarcely fell below 95° F. for weeks at a time, and was
often nearly 100° during the entire night, but the records at the
Health Office show that while cases of heatstroke were alarmingly
frequent, dysentery was unusually rare during the entire season.
That moisture cannot act more, at most, than as an occasional
predisposing cause of dysentery is sufficiently clear from the
statement of Hirsch, that of 119 epidemics, 62 commenced or were
preceded by wet and 57 by dry weather. In truth, dryness long continued
and excessive heat have already been invoked as remote causes of the
disease. But moisture, as contributing to, or being a necessary element
of, vegetable decomposition, the third characteristic of tropical
regions, is entitled to further consideration. Annesley observed that
among troops stationed in the vicinity of rivers, canals, and places
abounding with emanations from the decay of animal and vegetable
matters dysentery became extremely prevalent and assumed a more or less
malignant nature; and Baly, who studied the disease in its famous
outbreak in the Milbank Penitentiary, remarks that "it is greatest at
those seasons and in those states of the atmosphere which most favor
decomposition of organic matter in the soil."
In Africa it has been noticed that dysentery appears with the rainy
season, to disappear only at its close; and the same observation has
been made of Bengal, while in Lower Egypt the disease follows the
inundations of the Nile. Burkhardt says of 10,000 cases that one-half
occur in wet hot seasons, two-fifths in dry hot seasons, and but
one-tenth in cold seasons. Moreover, the removal of camping-grounds to
dry localities has often arrested the disease or checked its further
dissemination. Thus, Mursinna states that the removal of the army of
Prince Henry of Hesse from Nîmes, where the disease raged fearfully, to
Leitmeritz was attended by its immediate cessation, notwithstanding the
fact that the soldiers ate large quantities of fruit. A statement of
Dillenius, quoted by Heubner, is in this connection exceedingly
instructive: "Dillenius had to march with a dysentery hospital of more
than 500 patients from July 26 to August 3, 1812, and it required four
whole days to accomplish an ordinary nine or ten hours' march. The
patients, extremely exhausted, were finally put into a sheep-shed.
Here, in the fresh air and lying on hay, they all improved very
quickly. By advice of the physician they ate for medicine the fresh
whortleberries which they themselves had picked." Werneck attributes
the exemption of the city of Halle since the end of the last century to
the draining and drying of the neighboring marshes.
On the other hand, numerous observations go to prove that dysentery is
likewise prevalent in dry sandy soils where the factors so necessary to
the production of malaria are entirely unknown. Thus, Hirsch quotes
from Harthill to the effect that dysentery never occurred among the
English troops in Afghanistan until they entered upon its thoroughly
dry and sandy plains; and from Lidell, who declared that the disease
prevailed most in Panama in March, the dry season at this place. Again,
a striking confirmation of exemption from dysentery in a marshy region
{789} is offered in the Antilles at Grande-Terre, "a wet, marshy plain
severely visited by malaria, but used by patients attacked with chronic
dysentery at Basse-Terre as the safest place of refuge and recovery."
The rôle of moisture and vegetable decomposition may be, then, summed
up in the words of Annesley, that "all situations which furnish
exhalations from the decay of animal or vegetable productions under the
operation of a moist and hot state of the atmosphere will always
occasion dysentery in the predisposed subject--_circumstances which,
with other causes_ [italics ours], combine to generate the disease."
Atmospheric vicissitudes, checking of perspiration, catching cold, are
synonyms in the present popular as in the ancient professional
conception of the genesis of dysentery. "Of the remote causes of
dysentery," Johnson says, "I need say little; they are the same in all
parts of the world--atmospheric vicissitudes." And in making this
statement the author expresses the almost universal testimony of the
Indian physicians. "Sudden change of temperature," observes
Kaputschinsky of the Trans-Caucasus, where dysentery is rife, "is in
this region no rarity. The sultry heat of noon often alternates with a
cutting cold wind, and vice versâ. In the same place is now a warm, now
a cold, now a glowing hot breeze, and such changes most predispose to
dysentery." And McMullin says of the Barbadoes that "it is a curious
fact that this disease is most prevalent where from the immediate
contiguity of mountains sudden vicissitudes of temperature are
experienced." Didelot says also of South France, "It is not the fruits,
as people still believe to-day, which act as causes of dysentery, but
the sudden variations of the air." Ruthay remarks of the dysentery of
China that the most common cause is a chill caught by sleeping in a
draught uncovered or in the open air. Metzler attributes the exemption
of Stuttgart (since 1811) from any great epidemic to the fact that the
city lies in a valley open only to the east, which permits no contrast
of hot days and cold nights; and Seeger, in speaking of the epidemic
which occurred in Ludwigsberg in 1872 (a city of twelve thousand
population, where no epidemic of any kind had appeared since 1834, and
where 870 were suddenly attacked with dysentery) that it first broke
out in Kaffeeburg in two streets exposed to the wind, and thence spread
to different parts of the city. Exposure of the body, especially the
abdomen, during sleep or when perspiring, the sudden laying aside of
flannel body-clothes, are proceedings, Fayrer says, pregnant with
danger in dysenteric regions. A lamentable dysentery appeared,
according to Trotter, on board H.M.S. Berwick Oct., 1780, "in
consequence of the hurricane on the fifth of the month, by which the
clothes and bedding of the seamen, and indeed all parts of the ship,
were soaked in water, and many of the men slept for nights together on
the wet decks overcome with fatigue and debilitated from want of food."
Fayrer also quotes from Moseley the observation that "it often happens
that hundreds of men in a camp have been seized with the dysentery
almost at the same time after one shower of rain or from lying one
night in the wet and cold."
As illustrating the conjoined operation of all these various causes,
together with filth and foul effluvia, more especially exposure to
cold, the story of dysentery was never better told than by Sir James
MacGrigor, who, in speaking of the Peninsular campaign, remarks that
"the army during June as well as July was traversing Castile, where it
was {790} exposed to the direct influence of a burning sun darting its
rays through a sky without a single cloud, the troops marching and
fighting during the day, and bivouacking during the night on arid,
unsheltered plains. They felt at times every vicissitude of heat and
cold. In the rapid advance they could not be regularly supplied with
food or had not time to cook it, and not unfrequently indulged in bad
wine and unripe fruit." ... The thousands of sick (chiefly from
diarrhoea, dysentery, and remittent fever) were hurried off to Ciudad
Rodrigo, the nearest hospital-station to the frontier of Portugal, a
town "composed chiefly of ruins with very narrow streets," ... and from
having been "so much the object of contest, and alternately the site of
the hospitals of all the contending armies, nearly twenty thousand
bodies were calculated to have been put into the earth either in the
town or under its walls in the course of a few months." ... "It may
easily be conceived," the author adds, "in what state cases of
dysentery must have arrived after having sustained a journey in extent
from four to twenty days, conveyed chiefly in bullock-carts or on the
backs of mules, sometimes under incessant rain for several days
together."
It is really quite superfluous to cite further opinions or examples in
illustration of a fact which is so universally conceded as to be
exaggerated in its general significance. Taking cold is the common idea
of the cause of dysentery, and is always a satisfactory explanation in
a case of obscure origin in this or any disease, even though the
patient may be able to recall no possible exposure. The physician
himself contents himself only too easily with resort to this refuge,
and with further appeal to the locus minoris resistentiæ, as the
explanation of the seat of the disease, which he hopes to cure with the
aid of the vis medicatrix naturæ. But taking cold is only a popular
paraphrase for contracting a disease, and will bear no scientific
analysis of its meaning. Mere reduction of temperature will certainly
not produce a disease whose habitat is the hottest zone, nor will a
sudden chill of the surface be accepted as a sufficient cause so long
as men daily remain exempt after a sudden plunge into cold water. Some
other factor must be invoked to account for the outbreak of specific
(epidemic) dysentery.
The influence of the nervous system, the mechanical and chemical or
specific action of the ingesta and dejecta, remain to be especially
considered in the etiology of the disease.
The influence of the nervous system is more directly seen in the
production of diarrhoeas than dysenteries, but that sustained
disturbances of the emotions play an important part in the production
of dysentery is shown by the greater frequency of the disease among
prisoners of war. In the Franco-Prussian war the French prisoners
suffered more than the Germans, and the records of prison-life in our
own war, at Andersonville, Libby, and Salisbury, furnish ghastly
chapters in the history of this disease. Many other factors contribute
to the development of the disease under such circumstances--in fact,
all the cruelties of man's inhumanity to man--but the influence of the
nervous system is too plain to be mistaken. The communication between
the cervical ganglia and the sympathetic nerve-fibres which preside
over the cerebral circulation and regulate intestinal peristalsis has
been invoked (Glax) in explanation of the direct action of the brain
upon the intestinal canal. Curious in this {791} connection is the
claim of Savignac, who considered dysentery a disease of the nervous
system because in two cases he found spots of softening in the spinal
cord.