ON THE
MODE OF COMMUNICATION
OF
CHOLERA.
BY
JOHN SNOW, M.D.,
MEMBER OF THE ROYAL COLLEGE OF PHYSICIANS, FELLOW OF THE ROYAL MED. AND
CHIR. SOCIETY, FELLOW AND VICE-PRESIDENT OF THE MEDICAL SOCIETY OF
LONDON.
Second Edition, much Enlarged.
LONDON:
JOHN CHURCHILL, NEW BURLINGTON STREET.
M.DCCC.LV.
LONDON:
T. RICHARDS, 37 GREAT QUEEN STREET.
PREFACE TO THE SECOND EDITION.
The first edition of this work, which was published in August 1849, was
only a slender pamphlet. I have, since that time, written various papers
on the same subject, which have been read at the Medical Societies, and
published in the medical journals. The present edition contains the
substance of all these articles, together with much new matter, the
greater part of which is derived from my own recent inquiries.
I take this opportunity of expressing my thanks to the Registrar-General
for the facilities afforded me in making these inquiries.
I feel every confidence that my present labours will receive the same
kind consideration from the Medical Profession which has been accorded
to my former endeavours to ascertain the causes of cholera.
Sackville Street, Piccadilly,
11 December, 1854.
CONTENTS.
PAGE
Outline of the history of cholera 1
Cases proving its communication from person to person 3
Cholera not communicated by means of effluvia 9
The pathology of cholera indicates the manner in which it is
communicated 10
Analysis of the blood and evacuations in cholera 11 and 14
Cholera is propagated by the morbid poison entering the alimentary
canal 15
Evidence of this mode of communication in the crowded habitations
of the poor 17
—— amongst the mining population 19
Instances of the communication of cholera through the medium of
polluted water, in Horsleydown 23
—— at Albion Terrace, Wandsworth Road 25
—— at Ilford and near Bath 32
—— at Newburn on the Tyne 33
—— at Cunnatore 35
—— in the Black Sea Fleet 36
—— in the neighbourhood of Broad St., Golden Sq. 38
—— at Hampstead West End (the water being carried from Broad
Street) 44
Explanation of the Map showing the situation of the deaths in and
around Broad Street, Golden Square 45
Table of attacks and deaths near Golden Square 49
Outbreak of cholera at Deptford caused by polluted water 55
Communication of cholera by means of the water of rivers which
receive the contents of the sewers 56
Influence of the water supply on the epidemic of 1832, in London 57
Table showing the mortality from cholera, and the water supply 58
Influence of the water supply on the epidemic of 1849, in London 60
Table showing this influence 62
Communication of cholera by Thames water in the autumn of 1848 66
New water supply of the Lambeth Company 68
Effect of this new supply in the epidemic of autumn 1853 69
Tables showing this effect 71 and 73
Intimate mixture of the water supply of the Lambeth with that of
the Southwark and Vauxhall Company 74
Opportunity thus afforded of gaining conclusive evidence of the
effect of the water supply on the mortality from cholera 75
Account of inquiry for obtaining this evidence 77
Result of the inquiry as regards the first four weeks of the
epidemic of 1854 79
—— the first seven weeks of the same epidemic 82
Tables illustrating these results 84, 85
Inquiry of the Registrar-General respecting the effect of the
water supply of the above-mentioned Companies during the later
period of the epidemic 87
Comparison of the mortality of 1849 and 1854, in the districts
supplied by the above-named Companies 89
Effect of the water supply on the mortality from cholera amongst
the inmates of workhouses and prisons 91
Cholera in the district of the Chelsea Water Company 93
Effect of dry weather to increase the impurity of the Thames 95
Relation between the greater or less mortality from cholera in
London and the less or greater elevation of the ground 97
This relation shown to depend on the difference of water supply at
different elevations _ib._
Effect of water supply on the mortality of cholera in Birmingham,
Leicester, etc. 98
—— in Exeter 99
—— in Hull 100
—— in York 101
—— in Dumfries, etc. 102
—— in Nottingham and Glasgow 103
—— in Paris and Newcastle-upon-Tyne 104
Limited inquiry respecting the effect of the water supply at
Newcastle 107
Assent of the medical profession to the influence of polluted
water on the mortality from cholera 109
True explanation of this influence 110
Answers to certain objections 111
Circumstances connected with the history of cholera explained by
the principles advocated in this treatise, as,—
The duration of the epidemic in each place usually bears a
direct relation to the number of the population 115
The effect of season on the prevalence of cholera 117
Proportion of the sexes who die of cholera at different
periods of an epidemic, and under different circumstances 119
Proportion of deaths from cholera in certain occupations 121
Evidence that plague, yellow fever, dysentery, and typhoid fever
are communicated in the same way as cholera 125
Instances in which ague was caused by impure water 129
Measures required for the prevention of cholera and other diseases
which are communicated in the same way 133
Appendix, containing a list of the deaths from cholera which were
registered in the four weeks ending 5th August 1854, together
with the water supply of the houses in which the fatal attacks
took place, in all the sub-districts to which the supply of
either the Southwark and Vauxhall or the Lambeth Water Company
extends 138
MAPS.
Map 1. Showing the deaths from cholera in Broad Street, Golden Square,
and the neighbourhood, from 19th August to 30th September 1854. A black
mark or bar for each death is placed in the situation of the house in
which the fatal attack took place. The situation of the Broad Street
Pump is also indicated, as well as that of all the surrounding Pumps to
which the public had access.
Map 2. Showing the boundaries of the Registrar-General’s districts on
the south side of the Thames in London, and also the water supply of
those districts.
ON THE
MODE OF COMMUNICATION OF CHOLERA.
The existence of Asiatic Cholera cannot be distinctly traced back
further than the year 1769. Previous to that time the greater part of
India was unknown to European medical men; and this is probably the
reason why the history of cholera does not extend to a more remote
period. It has been proved by various documents, quoted by Mr. Scot,[1]
that cholera was prevalent at Madras in the year above mentioned, and
that it carried off many thousands of persons in the peninsula of India
from that time to 1790. From this period we have very little account of
the disease till 1814, although, of course, it might exist in many parts
of Asia without coming under the notice of Europeans.
In June 1814, the cholera appeared with great severity in the 1st bat.
9th regt. N.I., on its march from Jaulnah to Trichinopoly; while another
battalion, which accompanied it, did not suffer, although it had been
exposed to exactly the same circumstances, with one exception. Mr.
Cruikshanks, who attended the cases, made a report, which will be
alluded to further on.
[Sidenote: ON THE MODE OF COMMUNICATION OF CHOLERA.]
In 1817, the cholera prevailed with unusual virulence at several places
in the Delta of the Ganges; and, as it had not been previously seen by
the medical men practising in that part of India, it was thought by them
to be a new disease. At this time the cholera began to spread to an
extent not before known; and, in the course of seven years, it reached,
eastward, to China and the Philippine Islands; southward, to the
Mauritius and Bourbon; and to the north-west, as far as Persia and
Turkey. Its approach towards our own country, after it entered Europe,
was watched with more intense anxiety than its progress in other
directions. It would occupy a long time to give an account of the
progress of cholera over different parts of the world, with the
devastation it has caused in some places, whilst it has passed lightly
over others, or left them untouched; and unless this account could be
accompanied with a description of the physical condition of the places,
and the habits of the people, which I am unable to give, it would be of
little use.
There are certain circumstances, however, connected with the progress of
cholera, which may be stated in a general way. It travels along the
great tracks of human intercourse, never going faster than people
travel, and generally much more slowly. In extending to a fresh island
or continent, it always appears first at a sea-port. It never attacks
the crews of ships going from a country free from cholera, to one where
the disease is prevailing, till they have entered a port, or had
intercourse with the shore. Its exact progress from town to town cannot
always be traced; but it has never appeared except where there has been
ample opportunity for it to be conveyed by human intercourse.
There are also innumerable instances which prove the communication of
cholera, by individual cases of the disease, in the most convincing
manner. Instances such as the following seem free from every source of
fallacy.
I called lately to inquire respecting the death of Mrs. Gore, the wife
of a labourer, from cholera, at New Leigham Road, Streatham. I found
that a son of the deceased had been living and working at Chelsea. He
came home ill with a bowel complaint, of which he died in a day or two.
His death took place on August 18th. His mother, who attended on him,
was taken ill on the next day, and died the day following (August 20th).
There were no other deaths from cholera registered in any of the
metropolitan districts, down to the 26th August, within two or three
miles of the above place; the nearest being at Brixton, Norwood, or
Lower Tooting.
The first case of decided Asiatic cholera in London, in the autumn of
1848, was that of a seaman named John Harnold, who had newly arrived by
the _Elbe_ steamer from Hamburgh, where the disease was prevailing. He
left the vessel, and went to live at No. 8, New Lane, Gainsford Street,
Horsleydown. He was seized with cholera on the 22nd of September, and
died in a few hours. Dr. Parkes, who made an inquiry into the early
cases of cholera, on behalf of the then Board of Health, considered this
as the first undoubted case of cholera.
Now the next case of cholera, in London, occurred in the very room in
which the above patient died. A man named Blenkinsopp came to lodge in
the same room. He was attacked with cholera on the 30th September, and
was attended by Mr. Russell of Thornton Street, Horsleydown, who had
attended John Harnold. Mr. Russell informed me that, in the case of
Blenkinsopp, there were rice-water evacuations; and, amongst other
decided symptoms of cholera, complete suppression of urine from Saturday
till Tuesday morning; and after this the patient had consecutive fever.
Mr. Russell had seen a great deal of cholera in 1832, and considered
this a genuine case of the disease; and the history of it leaves no room
for doubt.
The following instances are quoted from an interesting work by Dr.
Simpson of York, entitled “Observations on Asiatic Cholera”:—“The first
cases in the series occurred at Moor Monkton, a healthy agricultural
village, situated to the north-west of York, and distant six miles from
that place. At the time when the first case occurred, the malady was not
known to be prevailing anywhere in the neighbourhood, nor, indeed, at
any place within a distance of thirty miles.
“John Barnes, aged 39, an agricultural labourer, became severely
indisposed on the 28th of December 1832; he had been suffering from
diarrhœa and cramps for two days previously. He was visited by Mr.
George Hopps, a respectable surgeon at Redhouse, who, finding him
sinking into collapse, requested an interview with his brother, Mr. J.
Hopps, of York. This experienced practitioner at once recognised the
case as one of Asiatic cholera; and, having bestowed considerable
attention on the investigation of that disease, immediately enquired for
some probable source of contagion, but in vain: no such source could be
discovered. When he repeated his visit on the day following, the patient
was dead; but Mrs. Barnes (the wife), Matthew Metcalfe, and Benjamin
Muscroft, two persons who had visited Barnes on the preceding day, were
all labouring under the disease, but recovered. John Foster, Ann Dunn,
and widow Creyke, all of whom had communicated with the patients above
named, were attacked by premonitory indisposition, which was however
arrested. Whilst the surgeons were vainly endeavouring to discover
whence the disease could possibly have arisen, the mystery was all at
once, and most unexpectedly, unravelled by the arrival in the village of
the son of the deceased John Barnes. This young man was apprentice to
his uncle, a shoemaker, living at Leeds. He informed the surgeons that
his uncle’s wife (his father’s sister) had died of cholera a fortnight
before that time, and that, as she had no children, her wearing apparel
had been sent to Monkton by a common carrier. The clothes had not been
washed; Barnes had opened the box in the evening; on the next day he had
fallen sick of the disease.
“During the illness of Mrs. Barnes, her mother, who was living at
Tockwith, a healthy village five miles distant from Moor Monkton, was
requested to attend her. She went to Monkton accordingly, remained with
her daughter for two days, washed hey daughter’s linen, and set out on
her return home, apparently in good health. Whilst in the act of walking
home she was seized with the malady, and fell down in collapse on the
road. She was conveyed home to her cottage, and placed by the side of
her bedridden husband. He, and also the daughter who resided with them,
took the malady. All the three died within two days. Only one other case
occurred in the village of Tockwith, and it was not a fatal case.” (p.
136.)
“A man came from Hull (where cholera was prevailing), by trade a
painter; his name and age are unknown. He lodged at the house of Samuel
Wride, at Pocklington; was attacked on his arrival on the 8th of
September, and died on the 9th. Samuel Wride himself was attacked on the
11th of September, and died shortly afterwards. These comprise the first
cases.
“The next was that of a person named Kneeshaw, who had been at Wride’s
house. But as this forms one of a series connected with the former,
furnished by Dr. Laycock, who has very obligingly taken the trouble to
verify the dates and facts of the latter part of the series, it will be
best to give the notes of these cases in that gentleman’s own words.
“‘My dear Dr. Simpson,—Mrs. Kneeshaw was attacked with cholera on
Monday, September 9th, and her son William on the 10th. He died on
Saturday the 15th; she lived three weeks; they lived at Pocklington. On
Sunday, September 16th, Mr. and Mrs. Flint, and Mr. and Mrs. Giles
Kneeshaw, and two children, went to Pocklington to see Mrs. Kneeshaw.
Mrs. Flint was her daughter. They all returned the same day, except Mr.
M. G. Kneeshaw, who stayed at Pocklington, until Monday, September 24th,
when he returned to York. At three o’clock on the same day, he was
attacked with cholera, and died Tuesday, September 25th, at three
o’clock in the morning. [There had been no cholera in York for some
time.] On Thursday, September 27th, Mrs. Flint was attacked, but
recovered. On Saturday, September 29th, her sister, Mrs. Stead, came
from Pocklington to York, to attend upon her; was attacked on Monday,
October the 1st, and died October the 6th.
“‘Mrs. Hardcastle, of No. 10, Lord Mayor’s Walk, York, was attacked with
cholera on October 3rd, and died the same day. Miss Agar, residing with
her, died of cholera on October 7th. Miss Robinson, who had come from
Hull to take care of the house, after the death of Mrs. Hardcastle and
Miss Agar, was attacked, and died on October 11th. Mr. C. Agar, of
Stonegate, York, went to see Mrs. Hardcastle on October 3rd, was
attacked next day, and died October 6th, early in the morning. On
Monday, October 8th, Mrs. Agar, the mother of Mr. C. Agar, was attacked,
and on the same day, one of the servants; both recovered. They had lived
with Mr. Agar. All the above dates and facts I have verified.
“‘I am, dear Dr. Simpson, yours very truly,
“‘T. LAYCOCK.
“‘Lendal, December 1st, 1849.’” (p. 160.)
Several other instances of the communication of cholera, quite as
striking as the above, are related in Dr. Simpson’s work.
The following account of the propagation of cholera has been published,
along with several other histories of the same kind, in a pamphlet by
Dr. Bryson.[2]
“Mr. Greene, of Fraserburgh, gives the following account of the
introduction of cholera into two villages in Scotland. Two boats, one
belonging to Cairnbulgh and the other to Inveralochy, met at Montrose,
and their crews on several occasions strolled through the town in
company, although aware that it was at that time infected with cholera.
On their passage homeward, they were obliged to put into Gourdon, where
one man belonging to the Cairnbulgh boat died on the 22nd of September,
after an illness of fourteen hours, with all the symptoms of cholera.
Several of the men of both boats were at the same time attacked with
serous diarrhœa, of which three of them had not recovered when they
reached their respective homes; nor indeed until the first cases of the
epidemic broke out in the villages.
“In Inveralochy the first case appeared on the 28th of September, three
or four days after the arrival of the boat; the sufferer, the father of
one of the crew, had been engaged in removing the cargo along with other
members of his family. Two other cases occurred in this family; one on
the 30th of September, and one on the 1st of October.
“In Cairnbulgh, the first cases appeared on the 29th and 30th of
September respectively, and both patients had also been engaged in
removing the cargo of the boat (shell-fish) belonging to that village.
No other cases appeared until the 3rd of October; so that from the 28th
of September to the 3rd of October none were attacked in either village,
but those who had come in contact with the suspected boats, or their
crews.
“The subsequent cases were chiefly among relatives of those first
attacked; and the order of their propagation was as follows. In
Inveralochy, the first case was the father of a family; the second, his
wife; the third, a daughter living with her parents; the fourth, a
daughter who was married and lived in a different house, but who
attended her father and mother during their illness; the fifth, the
husband of the latter; and the sixth, his mother. Other cases occurred
at the same time, although they were not known to have communicated with
the former. One of them was the father of a family; the second his son,
who was seized the day after his father, and a daughter the next day.”
The following instances of communication of cholera are taken from
amongst many others in the “Report on Epidemic Cholera to the Royal
College of Physicians”, by Dr. Baly.
“Stockport. (Dr. Rayner and Mr. J. Rayner, reporters). Sarah Dixon went
to Liverpool, September 1st, to bury her sister, who had died of cholera
there; returned to Stockport on September 3rd; was attacked with cholera
on the 4th; was taken home by her mother to her mother’s house, a
quarter of a mile distant; was in collapse, but recovered. Her mother
was attacked on the 11th, and died. The brother, James Dixon, came from
High Water to see his mother, and was attacked on the 14th.
“Liverpool. (Mr. Henry Taylor, reporter.) A nurse attended a patient in
Great Howard Street (at the lower part of the town), and on her return
home, near Everton (the higher part of the town), was seized, and died.
The nurse who attended her was also seized, and died. No other case had
occurred previously in that neighbourhood, and none followed for about a
fortnight.
“Hedon. (Dr. Sandwith, reporter.) Mrs. N. went from Paul, a village
close to the Humber, to Hedon, two miles off, to nurse her brother in
cholera; the next day, after his death, went to nurse Mrs. B., also at
Hedon; within two days was attacked herself; was removed to a
lodging-house; the son of the lodging-house keeper was attacked the next
day, and died. Mrs. N.’s son removed her back to Paul; was himself
attacked two days afterwards, and died.”
It would be easy, by going through the medical journals and works which
have been published on cholera, to quote as many cases similar to the
above as would fill a large volume. But the above instances are quite
sufficient to show that cholera can be communicated from the sick to the
healthy; for it is quite impossible that even a tenth part of these
cases of consecutive illness could have followed each other by mere
coincidence, without being connected as cause and effect.
Besides the facts above mentioned, which prove that cholera is
communicated from person to person, there are others which show, first,
that being present in the same room with a patient, and attending on
him, do not necessarily expose a person to the morbid poison; and,
secondly, that it is not always requisite that a person should be very
near a cholera patient in order to take the disease, as the morbid
matter producing it may be transmitted to a distance. It used to be
generally assumed, that if cholera were a catching or communicable
disease, it must spread by effluvia given off from the patient into the
surrounding air, and inhaled by others into the lungs. This assumption
led to very conflicting opinions respecting the disease. A little
reflection shews, however, that we have no right thus to limit the way
in which a disease may be propagated, for the communicable diseases of
which we have a correct knowledge spread in very different manners. The
itch, and certain other diseases of the skin, are propagated in one way;
syphilis, in another way; and intestinal worms in a third way, quite
distinct from either of the others.
A consideration of the pathology of cholera is capable of indicating to
us the manner in which the disease is communicated. If it were ushered
in by fever, or any other general constitutional disorder, then we
should be furnished with no clue to the way in which the morbid poison
enters the system; whether, for instance, by the alimentary canal, by
the lungs, or in some other manner, but should be left to determine this
point by circumstances unconnected with the pathology of the disease.
But from all that I have been able to learn of cholera, both from my own
observations and the descriptions of others, I conclude that cholera
invariably commences with the affection of the alimentary canal. The
disease often proceeds with so little feeling of general illness, that
the patient does not consider himself in danger, or even apply for
advice, till the malady is far advanced. In a few cases, indeed, there
are dizziness, faintness, and a feeling of sinking, before discharges
from the stomach or bowels actually take place; but there can be no
doubt that these symptoms depend on the exudation from the mucous
membrane, which is soon afterwards copiously evacuated. This is only
what occurs in certain cases of hæmorrhage into the alimentary canal,
where all the symptoms of loss of blood are present before that fluid
shows itself in the evacuations. In those rare cases, called “cholera
sicca,” in which no purging takes place, the intestines have been found
distended with the excretion peculiar to the disease, whenever an
examination of the body has taken place after death. In all the cases of
cholera that I have attended, the loss of fluid from the stomach and
bowels has been sufficient to account for the collapse, when the
previous condition of the patient was taken into account, together with
the suddenness of the loss, and the circumstance that the process of
absorption appears to be suspended.
The symptoms which follow the affection of the alimentary canal in
cholera are exactly those which this affection is adequate, and, indeed,
could not fail to produce. The analyses which have been made of the
blood of cholera patients, show that the watery fluid effused into the
stomach and bowels is not replaced by absorption, or is replaced only to
a small extent. The analyses of Dr. O’Shaughnessy and others, during the
cholera of 1831–32, show that the amount of water in the blood was very
much diminished in proportion to the solid constituents, and that the
salts of the blood were also diminished. The analyses of Dr. Garrod and
Dr. Parkes, in the spring of 1849, were more numerous and exact.[3] The
amount of water in the blood of healthy persons is on the average 785
parts in 1000; whereas, in the average of the analyses performed by Drs.
Garrod and Parkes, it was only 733 parts, while the amount of solid
constituents of the blood, relatively to the water, was increased from
215—the healthy standard—to 267. The globules, together with the albumen
and other organic constituents of the serum, amount in the healthy state
to 208 parts in 1000, while in the blood of cholera patients they
amounted to 256 parts. The saline constituents in 1000 parts of blood
are somewhat increased, on account of the great diminution of water;
but, when estimated in relation to the other solid ingredients, or to
the whole quantity existing in the healthy body, the amount is
diminished. Dr. Garrod is of the opinion that a chemical analysis will
determine whether or not a specimen of blood has been derived from a
cholera patient.
The stools and vomited matters in cholera consist of water, containing a
small quantity of the salts of the blood, and a very little albuminous
substance. The change in the blood is precisely that which the loss by
the alimentary canal ought to produce; and, indeed, it is physically
impossible that the alteration in the blood can be caused in any other
way. The sweating which takes place in an advanced stage of the disease
may increase the density of the blood to a trifling extent; but it does
not come on till the blood is already altered, and it is only a
consequence of the diminished force of the circulation, like the
sweating met with in collapse from hæmorrhage or severe injuries, and in
faintness from venesection.
The loss of water from the blood causes it to assume the thick tarry
appearance, so well known to all who have opened a vein in cholera. The
diminished volume of the blood causes many of the symptoms of a true
hæmorrhage, as debility, faintness, and coldness; while these effects
are much increased by its thick and tenacious condition, which impedes
its passage through the pulmonary capillaries, thereby reducing the
contents of the arteries throughout the system to the smallest possible
amount, as indicated by the small thready pulse. The interruption to the
pulmonary circulation occasioned by the want of fluidity of the blood,
is the cause of the distressing feeling of want of breath. Proofs of the
obstructed circulation through the lungs generally remain after death,
in the distended state of the pulmonary arteries and right cavities of
the heart. The deficient supply of blood to the various organs, and its
unfitness to pass through the capillaries, are the cause of the
suppression of the renal, biliary, and other secretions. The cramps
appear to consist chiefly of reflex action, caused by the irritation,
and probably the distension, of the bowels.
If any further proof were wanting than those above stated, that all the
symptoms attending cholera, except those connected with the alimentary
canal, depend simply on the physical alteration of the blood, and not on
any cholera poison circulating in the system, it would only be necessary
to allude to the effects of a weak saline solution injected into the
veins in the stage of collapse. The shrunken skin becomes filled out,
and loses its coldness and lividity; the countenance assumes a natural
aspect; the patient is able to sit up, and for a time seems well. If the
symptoms were caused by a poison circulating in the blood, and
depressing the action of the heart, it is impossible that they should
thus be suspended by an injection of warm water, holding a little
carbonate of soda in solution.
It has often been contended that the collapse of cholera cannot be the
mere result of the purging and vomiting, because, in some of the most
rapid and malignant cases, the amount of the stools and vomited fluid is
less than in milder and more protracted ones, or even in some cases in
which the patients recover. But, in the most rapid and malignant cases,
there is sufficient loss of aqueous fluid by the alimentary canal to
alter the blood into the thick tenacious state peculiar to this disease;
and the fact of more purging occurring in other cases which are more
protracted, only proves that, in these latter, absorption from the
stomach and intestines has not been altogether arrested, or that the
stools have been diluted with fluids drank by the patient. The loss of
fluid in every case of fully developed cholera must be sufficient to
cause the thickened state of the blood, which is the cause of the algide
symptoms; and the amount of malignancy of the case must depend chiefly
on the extent to which the function of absorption is impaired.
If absorption were altogether arrested in every case of cholera from the
beginning, the amount of discharge from the alimentary canal would not
equal that of a fatal hæmorrhage, for the thickened blood which remains
is certainly not able to maintain life so well as the same quantity of
healthy blood. Indeed, it is easy to calculate the amount of fluid
separated from the blood, by means of the analyses previously quoted,
and others which have been made of the cholera stools. In some analyses
of these evacuations made by Dr. Parkes,[4] the average composition in
1,000 parts was found to be 982.4 water and 17.6 solids; consequently,
the problem is merely to find how much of such a fluid requires to be
subtracted from blood consisting of water 785 and solids 215, in 1000
parts, in order to reduce it to blood consisting of water 733 and solids
267. The answer to this problem is that 208.5 parts would require to be
subtracted from 1000 parts of blood. M. Valentin has estimated the
average amount of blood in the human adult at thirty pounds; and,
therefore, the whole quantity of fluid that requires to be effused into
the stomach and bowels, in order to reduce the blood of a healthy adult
individual to the condition in which it is met with in the collapse of
cholera is, on the average, 100 ounces, or five imperial pints. This
calculation may be useful as indicating the amount of fluid which ought
not to be exceeded in the injection of the blood vessels.
Diseases which are communicated from person to person are caused by some
material which passes from the sick to the healthy, and which has the
property of increasing and multiplying in the systems of the persons it
attacks. In syphilis, small-pox, and vaccinia, we have physical proof of
the increase of the morbid material, and in other communicable diseases
the evidence of this increase, derived from the fact of their extension,
is equally conclusive. As cholera commences with an affection of the
alimentary canal, and as we have seen that the blood is not under the
influence of any poison in the early stages of this disease,[5] it
follows that the morbid material producing cholera must be introduced
into the alimentary canal—must, in fact, be swallowed accidentally, for
persons would not take it intentionally; and the increase of the morbid
material, or cholera poison, must take place in the interior of the
stomach and bowels. It would seem that the cholera poison, when
reproduced in sufficient quantity, acts as an irritant on the surface of
the stomach and intestines, or, what is still more probable, it
withdraws fluid from the blood circulating in the capillaries, by a
power analogous to that by which the epithelial cells of the various
organs abstract the different secretions in the healthy body. For the
morbid matter of cholera having the property of reproducing its own
kind, must necessarily have some sort of structure, most likely that of
a cell. It is no objection to this view that the structure of the
cholera poison cannot be recognised by the microscope, for the matter of
small-pox and of chancre can only be recognised by their effects, and
not by their physical properties.
The period which intervenes between the time when a morbid poison enters
the system, and the commencement of the illness which follows, is called
the period of incubation. It is, in reality, a period of reproduction,
as regards the morbid matter; and the disease is due to the crop or
progeny resulting from the small quantity of poison first introduced. In
cholera, this period of incubation or reproduction is much shorter than
in most other epidemic or communicable diseases. From the cases
previously detailed, it is shown to be in general only from twenty-four
to forty-eight hours. It is owing to this shortness of the period of
incubation, and to the quantity of the morbid poison thrown off in the
evacuations, that cholera sometimes spreads with a rapidity unknown in
other diseases.
The mode of communication of cholera might have been the same as it is,
even if it had been a disease of the blood; for there is a good deal of
evidence to show that plague, typhoid fever, and yellow fever, diseases
in which the blood is affected, are propagated in the same way as
cholera. There is sufficient evidence also, I believe, in the following
pages, to prove the mode of communication of cholera here explained,
independently of the pathology of the disease; but it was from
considerations of its pathology that the mode of communication was first
explained, and, if the views here propounded are correct, we had a
knowledge of cholera, before it had been twenty years in Europe, more
correct than that of most of the older epidemics; a knowledge which,
indeed, promises to throw much light on the mode of propagation of many
diseases which have been present here for centuries.
The instances in which minute quantities of the ejections and dejections
of cholera patients must be swallowed are sufficiently numerous to
account for the spread of the disease; and on examination it is found to
spread most where the facilities for this mode of communication are
greatest. Nothing has been found to favour the extension of cholera more
than want of personal cleanliness, whether arising from habit or
scarcity of water, although the circumstance till lately remained
unexplained. The bed linen nearly always becomes wetted by the cholera
evacuations, and as these are devoid of the usual colour and odour, the
hands of persons waiting on the patient become soiled without their
knowing it; and unless these persons are scrupulously cleanly in their
habits, and wash their hands before taking food, they must accidentally
swallow some of the excretion, and leave some on the food they handle or
prepare, which has to be eaten by the rest of the family, who, amongst
the working classes, often have to take their meals in the sick room:
hence the thousands of instances in which, amongst this class of the
population, a case of cholera in one member of the family is followed by
other cases; whilst medical men and others, who merely visit the
patients, generally escape. The _post mortem_ inspection of the bodies
of cholera patients has hardly ever been followed by the disease that I
am aware, this being a duty that is necessarily followed by careful
washing of the hands; and it is not the habit of medical men to be
taking food on such an occasion. On the other hand, the duties performed
about the body, such as laying it out, when done by women of the working
class, who make the occasion one of eating and drinking, are often
followed by an attack of cholera; and persons who merely attend the
funeral, and have no connexion with the body, frequently contract the
disease, in consequence, apparently, of partaking of food which has been
prepared or handled by those having duties about the cholera patient, or
his linen and bedding.
[Sidenote: PREVALENCE OF CHOLERA IN THE MINING DISTRICTS.]
Deficiency of light is a great obstacle to cleanliness, as it prevents
dirt from being seen, and it must aid very much the contamination of the
food with the cholera evacuations. Now the want of light, in some of the
dwellings of the poor, in large towns, is one of the circumstances that
has often been commented on as increasing the prevalence of cholera.
The involuntary passage of the evacuations in most bad cases of cholera,
must also aid in spreading the disease. Mr. Baker, of Staines, who
attended two hundred and sixty cases of cholera and diarrhœa in 1849,
chiefly among the poor, informed me, in a letter with which he favoured
me in December of that year, that “when the patients passed their stools
involuntarily the disease evidently spread.” It is amongst the poor,
where a whole family live, sleep, cook, eat, and wash in a single room,
that cholera has been found to spread when once introduced, and still
more in those places termed common lodging-houses, in which several
families were crowded into a single room. It was amongst the vagrant
class, who lived in this crowded state, that cholera was most fatal in
1832; but the Act of Parliament for the regulation of common
lodging-houses, has caused the disease to be much less fatal amongst
these people in the late epidemics. When, on the other hand, cholera is
introduced into the better kind of houses, as it often is, by means that
will be afterwards pointed out, it hardly ever spreads from one member
of the family to another. The constant use of the hand-basin and towel,
and the fact of the apartments for cooking and eating being distinct
from the sick room, are the cause of this.
The great prevalence of cholera in institutions for pauper children and
pauper lunatics, whenever it has gained access to these buildings, meets
with a satisfactory explanation according to the principles here laid
down. In the asylum for pauper children at Tooting, one hundred and
forty deaths from cholera occurred amongst a thousand inmates, and the
disease did not cease till the remaining children had been removed. The
children were placed two or three in a bed, and vomited over each other
when they had the cholera. Under these circumstances, and when it is
remembered that children get their hands into everything, and are
constantly putting their fingers in their mouths, it is not surprising
that the malady spread in this manner, although I believe as much
attention was paid to cleanliness as is possible in a building crowded
with children. Pauper lunatics are generally a good deal crowded
together, especially in their sleeping wards, and as the greater number
of them are in a state of imbecility, they are no more careful than
children in the use of their hands. It is with the greatest difficulty
that they can be kept even moderately clean. As might be expected,
according to the views here explained, the lunatic patients generally
suffered in a much greater proportion than the keepers and other
attendants.
The mining population of Great Britain has suffered more from cholera
than persons in any other occupation,—a circumstance which I believe can
only be explained by the mode of communication of the malady above
pointed out. Pitmen are differently situated from every other class of
workmen in many important particulars. There are no privies in the
coal-pits, or, as I believe, in other mines. The workmen stay so long in
the mines that they are obliged to take a supply of food with them,
which they eat invariably with unwashed hands, and without knife and
fork. The following is a reply which I received from a relative of mine
connected with a colliery near Leeds, in answer to an inquiry I made:—
“Our colliers descend at five o’clock in the morning, to be ready for
work at six, and leave the pit from one to half-past three. The average
time spent in the pit is eight to nine hours. The pitmen all take down
with them a supply of food, which consists of cake, with the addition,
in some cases, of meat; and all have a bottle, containing about a quart
of ‘drink’. I fear that our colliers are no better than others as
regards cleanliness. The pit is one huge privy, and of course the men
always take their victuals with unwashed hands.”
It is very evident that, when a pitman is attacked with cholera whilst
at work, the disease has facilities for spreading among his
fellow-labourers such as occur in no other occupation. That the men are
occasionally attacked whilst at work I know, from having seen them
brought up from some of the coal-pits in Northumberland, in the winter
of 1831–2, after having had profuse discharges from the stomach and
bowels, and when fast approaching to a state of collapse.
Dr. Baly, who has done me the honour of giving a very full and impartial
account of my views in his “Report on Cholera to the College of
Physicians”, makes the objection to what I have said about the colliers,
that the women and children who do not work in the mines, were attacked
in as large numbers as the men. I believe, however, that this is only
what ought to occur from the propagation of the cholera in the crowded
dwellings of the pitmen, in the manner previously explained. The only
effect of its communication in the pits would be, that the men and boys
in a family would have the cholera a day or two earlier than the women
and children; and if a special inquiry were made on this point, this
would probably be found to be the case. It has often been said that, if
cholera were a communicable disease, women ought to suffer in much
greater numbers than the men, as they are employed in nursing the sick.
I leave this objection and Dr. Baly’s to combat each other.
It is very probable that, when cholera occurs amongst people who are
employed in the preparation or vending of provisions, the disease may be
spread by this means, although from the nature of the subject it is
hardly to be expected that the fact would be discovered. The following
cases, perhaps, afford as decisive proof of this variety of
communication of cholera as can be expected. In the beginning of 1850, a
letter appeared in the _Provincial Medical and Surgical Journal_, from
Mr. John C. Bloxam, in the Isle of Wight, being an answer to the inquiry
on cholera by Mr. Hunt. Among other interesting information, Mr. Bloxam
stated, that the only cases of cholera that occurred in the village of
Carisbrook, happened in persons who ate of some stale cow-heels, which
had been the property of a man who died in Newport, after a short and
violent attack of cholera. Mr. Bloxam kindly made additional personal
inquiries into the case, in consequence of questions I put to him, and
the following is a summary of the information contained in his letter:—
[Sidenote: COMMUNICATION OF CHOLERA BY POLLUTED WATER.]
The man from whose house the cow-heels were sent for sale died on
Monday, the 20th of August. It was the custom in the house to boil these
articles on Monday, Wednesday, and Friday; and the cow-heels under
consideration were taken to Carisbrook, which is a mile from Newport,
ready boiled, on Tuesday the 21st. Eleven persons in all partook of this
food, seven of whom ate it without any additional cooking. Six of these
were taken ill within twenty-four hours after eating it, five of whom
died, and one recovered. The seventh individual, a child, who ate but a
small quantity of the cow-heels, was unaffected by it. Four persons
partook of the food after additional cooking. In one case the cow-heels
were fried, and the person who ate them was taken ill of cholera within
twenty-four hours afterwards, and died. Some of the food was made into
broth, of which three persons partook while it was warm; two of them
remained well, but the third person partook again of the broth next day,
when cold, and, within twenty-four hours after this latter meal, she was
taken ill with cholera, of which she died. It may be proper to mention,
although it is no unusual circumstance for animal food to be eaten in
hot weather when not quite fresh, that some of the persons perceived the
cow-heels to be not so fresh as they ought to have been at the time they
were eaten, and part of them had to be thrown away a day or two
afterwards, in consequence of being quite putrid.
It is not unlikely that some of the cases of cholera which spring up
without any apparent connection with previous cases, may be communicated
through articles of diet. It is the practice of the poor people, who
gain a living by selling fruit and other articles in the streets, to
keep their stock in the very crowded rooms in which they live, and, when
visiting the out-patients of a medical charity a few years ago, I often
saw baskets of fruit pushed under the beds of sick patients, in close
proximity with the chamber utensils. I need hardly say that if cases of
disease were propagated in this way, it would be quite impossible to
trace them.
If the cholera had no other means of communication than those which we
have been considering, it would be constrained to confine itself chiefly
to the crowded dwellings of the poor, and would be continually liable to
die out accidentally in a place, for want of the opportunity to reach
fresh victims; but there is often a way open for it to extend itself
more widely, and to reach the well-to-do classes of the community; I
allude to the mixture of the cholera evacuations with the water used for
drinking and culinary purposes, either by permeating the ground, and
getting into wells, or by running along channels and sewers into the
rivers from which entire towns are sometimes supplied with water.
In 1849 there were in Thomas Street, Horsleydown, two courts close
together, consisting of a number of small houses or cottages, inhabited
by poor people. The houses occupied one side of each court or alley—the
south side of Trusscott’s Court, and the north side of the other, which
was called Surrey Buildings, being placed back to back, with an
intervening space, divided into small back areas, in which were situated
the privies of both the courts, communicating with the same drain, and
there was an open sewer which passed the further end of both courts.
Now, in Surrey Buildings the cholera committed fearful devastation,
whilst in the adjoining court there was but one fatal case, and another
case that ended in recovery. In the former court, the slops of dirty
water, poured down by the inhabitants into a channel in front of the
houses, got into the well from which they obtained their water; this
being the only difference that Mr. Grant, the Assistant-Surveyor for the
Commissioners of Sewers, could find between the circumstances of the two
courts, as he stated in a report that he made to the Commissioners. The
well in question was supplied from the pipes of the Southwark and
Vauxhall Waterworks, and was covered in on a level with the adjoining
ground; and the inhabitants obtained the water by a pump placed over the
well. The channel mentioned above commenced close by the pump. Owing to
something being out of order, the water had for some time occasionally
burst out at the top of the well, and overflowed into the gutter or
channel, afterwards flowing back again mixed with the impurities; and
crevices were left in the ground or pavement, allowing part of the
contents of the gutter to flow at all times into the well; and when it
was afterwards emptied, a large quantity of black and highly offensive
deposit was found.