as regards particular bacteria, that it can modify the subtle
properties of toxic solutions, and we are asked to believe that it may
exercise an important influence on the animal system in determining
the power of the latter to deal with the agents of disease; but, as we
have seen, the mechanism of it all is shrouded in mystery, and we are
at a loss to divine how it works. Might not some fresh light be thrown
upon this problem if we could ascertain the effect of sunshine on some
of these natural fluids of the body, which recent brilliant research
has shown to be endowed with such wonderful protective or immunising
properties? So far as I am aware, the action of sunshine on these
anti-toxins or protective fluids has not yet been investigated. Can
sunshine interfere with the therapeutic effect of diphtheria-serum,
for example? If simple insolation can so profoundly modify the
character of toxic fluids, it is not unreasonable to anticipate some
action on these anti-toxins, and their study in this connection would
appear to offer an important step in the direction of unravelling the
mystery attending the action of light on life.
BACTERIOLOGY AND WATER
Whilst the Hamburg cholera disaster of 1892 will certainly rank in the
annals of epidemiology as one of the great catastrophes of recent
times, it will also be memorable as one of the most instructive which
has ever taken place.
It is perhaps not unnatural that this should be the case, for since
the last European epidemic of importance our study of the principles
of sanitation has received a new impetus, and this impetus must be in
great part ascribed to the science of bacteriology, which has sprung
into existence within the past two decades. We have now no longer to
confront mysterious and unknown morbific material, but have been
brought face to face with some of the most dreaded foes of the human
race. We are no longer groping, as it were, in the dark, but have a
definite object, in the shape of well-recognised micro-organisms
associated with specific zymotic diseases, for our common crusade.
But it is the light which has been thrown for the first time upon
numerous intricate problems connected with the sanitary aspects of
public water-supplies which constitutes not the least important of the
many services rendered by bacteriology to the public. Perhaps one of
the most striking of these may be considered the insight which it has
afforded into the value of various processes of water-purification,
furnishing us with the most subtle and searching tests, surpassing in
delicacy those of the most refined chemical methods.
Thus for years the processes of sand-filtration, as practised at
waterworks in dealing with river and other surface waters, were
regarded by chemical experts as of but little or no value, because, on
chemical analysis, but little or no difference was found to exist
between the filtered and unfiltered samples respectively. Water
engineers started this method of water treatment in London as far back
as the year 1839, with no other object than the distribution of a
water bright and clear on delivery, but, unknown to themselves, they
were carrying out a system of water-purification the nature and extent
of which has been left to the infant science of bacteriology to
unravel and reveal.
It was in the year 1885 that Dr. Koch's new bacteriological
water-tests were introduced, and systematically applied for the first
time to the London water-supply by Professor Percy Frankland, and the
entirely unexpected result obtained, that whereas the River Thames
water at Hampton contained as many as 1,644 micro-organisms in about
twenty drops, this water, after passing through the sand-filters,
possessed as few as thirteen in the same number of drops. The
remarkable purification effected in the treatment of the water was
thus very clearly shown, and an entirely new aspect was given to the
processes of sand-filtration.
The importance of these results was quickly appreciated by the
official water-examiner, the late Sir Francis Bolton, and at the
request of the Local Government Board regular monthly bacteriological
examinations of the London water-supply were conducted.
It is amusing to recall that, at the time when these results were
first published, the public, instead of being reassured by these
facts, were greatly alarmed, and it is a matter of history that the
mere demonstration of the presence of micro-organisms in
drinking-water caused a fall in the price of several of the water
companies' stocks!
These investigations, which have since been confirmed by others both
in this country and on the Continent, have clearly shown, then, that
sand-filtration, when carefully carried out, offers a most remarkable
and obstinate barrier to the passage of microbes, and there was every
justification in presuming that if disease organisms should at any
time be present in the raw untreated water, they would also undergo a
similar fate, as there was no reasonable ground for supposing that
they would behave any differently from the ordinary harmless water
bacteria.
But this was a hypothesis only, and, however satisfactory experiments
in this direction made in the laboratory might prove, there was always
the uncertainty attaching to a fact which had not passed through the
ordeal of practical experience.
The answer to this searching and all-important question has been
furnished in the most conclusive manner by the history of the cholera
epidemic in Hamburg and Altona respectively in the year 1892.
These two cities are both dependent upon the River Elbe for their
water-supply, but whereas in the case of Hamburg the intake is
situated _above_ the city, the supply for Altona is abstracted below
Hamburg _after it has received the sewage of a population of close
upon 800,000 persons_. The Hamburg water was, therefore, to start
with, relatively pure when compared with that destined for the use of
Altona. But what was the fate of these two towns as regards cholera?
Situated side by side, absolutely contiguous, in fact, with nothing in
their surroundings or in the nature of their population to especially
distinguish them, in the one cholera swept away thousands, whilst in
the other the scourge was scarcely felt; in Hamburg the deaths from
cholera amounted to 1,250 per 100,000, and in Altona to but 221 per
100,000 of the population. So clearly defined, moreover, was the path
pursued by the cholera, that although it pushed from the Hamburg side
right up to the boundary line between the two cities, it there
stopped, this being so striking that in one street, which for some
distance marks the division between these cities, _the Hamburg side
was stricken down with cholera, whilst that belonging to Altona
remained free_. The remarkable fact was brought to light that in those
houses supplied with the Hamburg water cholera was rampant, whilst in
those on the Altona side and furnished with the Altona water not one
case occurred.
We have seen that the Hamburg water, to start with, was comparatively
pure when compared with the foul liquid abstracted from the Elbe by
Altona, but whereas in the one case the water was submitted to
exhaustive and careful filtration through sand before delivery, in
Hamburg the Elbe water was distributed in its raw condition as drawn
from the river.
But further testimony was afforded later to the truth of these
results, for during the winter, whilst the cases of cholera had almost
completely died out in Hamburg, suddenly a most unexpected and
unaccountable recrudescence of the epidemic occurred, and this time in
Altona. This outbreak could not be traced to any direct infection from
Hamburg, but must have arisen in Altona itself. In all about
forty-seven cases were recorded between December 23rd, 1892, and
February 12th, 1893. A searching inquiry was instituted, and it was
ascertained that the number of bacteria found in the filtered water,
usually about fifty, had during these months risen to as many as 1,000
and more in about twenty drops of water, clearly indicating that the
filtration of the water was not being efficiently carried out. That
this was actually the case was proved by the fact that one of the
sand-filters which had been cleaned during the frost had become frozen
over, and was not able to retain the bacteria. That the outbreak did
not become more serious Koch ascribes to the fact that this, to all
intents and purposes raw untreated water, was largely diluted with
efficiently filtered water before delivery. Dr. Koch, who personally
superintended this inquiry in Altona, traced another local outbreak of
cholera in the city to the use of a well-water obviously open to
pollution, which was used by about 270 persons. In one of the houses
employing this water, and in the immediate vicinity of the well, a boy
died of cholera on January 23rd, and during the week following a
number of cases occurred amongst persons using this source. On
discovering the cholera bacilli in this polluted water, its
contamination was placed beyond doubt, and five days after the well
was closed all cases ceased in the locality.
There cannot be any longer a doubt as to the value of sand-filtration
as a means of water-purification, but the responsibility which we have
seen attaches to this treatment of water cannot be exaggerated, for
whilst when efficiently pursued it forms a most important barrier to
the dissemination of disease germs, the slightest imperfection in its
manipulation is a constant menace during any epidemic.
It is, as a rule, during the winter months that the largest number of
bacteria are present in the filtered water, and it is therefore of
especial importance that during this season, when the raw river water
is generally richest in bacterial life, and when, therefore, the
filters are most taxed and the consequences of frost are most to be
apprehended, that those entrusted with this responsible task should be
unremitting in their endeavours to obtain a good filtrate.
That waters submitted to exhaustive natural filtration, such as those
derived from deep wells sunk into the chalk, and usually almost
entirely devoid of bacterial life, may at times become the carriers of
disease has been proved by the disastrous outbreak of typhoid fever
which occurred some years ago at Worthing.
This town has long been supplied with water of the very finest quality
for dietetic purposes, and nothing could have been more unexpected
than this most fatal epidemic. It must, however, be borne in mind that
such deep-well waters are not necessarily immaculate, for in the event
of any fault in the water-bearing strata occurring, the filtration
becomes inefficient, and the water may then, as in the case of
Worthing, be the bearer and disseminator of zymotic disease.
The bacteriological methods for the examination of water, although
when first introduced but a few years ago were lightly looked upon,
and by many opposed, have now become of paramount importance in all
questions of water-purification. The immense mass of evidence of a
purely bacteriological character which was taken, and indeed required
by the Royal Commissioners of 1893 on the London water-supply,
indicates clearly enough the change which has taken place in the
public estimation of the value of these methods; and it is highly
significant that in their report the Commissioners lay stress upon the
importance of extensive storage and efficient filtration, two factors
the meaning and worth of which rest almost entirely on the results of
bacteriological research.
Cholera is not, however, the only water-carried disease which has
borne eloquent testimony to the services rendered by the efficient
purification of public water-supplies. The experience of the State of
Massachusetts in America, in regard to typhoid fever and
drinking-water, is also exceedingly instructive.
Massachusetts has, by creating a Board of Health, and affording the
same every facility for the prosecution of hygienic investigations of
the greatest importance, laid the whole scientific world under a deep
obligation. The reports issued have a very wide circulation, and
embrace a variety of subjects, but second to none in interest and
importance is the account of the experimental work carried out by the
officials of the Board on the purification of water and sewage. These
experiments have become classical, and have been conducted with a zeal
and thoroughness which deserve the highest praise. It is in looking at
the results achieved by the city of Lawrence in regard to its
water-supply that some conception can be obtained of the immense
importance to the community of the scientific experiments conducted in
the State Laboratory. No expense has been spared, and for years past
elaborate and costly experiments on a large scale have been carried
out to determine the most efficient manner in which water may be
rendered fit and safe for drinking.
Now the death-rate in a community from typhoid fever may be taken as
an index of the general sanitary conditions prevailing in such a
community, the character of the public water-supply, not without
justification, being regarded as a prime factor in its determination.
One of the most significant points in the sanitary history of the
State of Massachusetts is the almost uniform decline in the mortality
from typhoid fever in proportion as measures have been taken to
introduce better water-supplies and to improve those which already
exist. Thus in the twenty years, from 1856 to 1876, the death-rate
from this disease was 8·6 per 10,000 of population, whilst in the
period from 1876 to 1895 it had fallen to 4·1 per 10,000, the
improvement in respect of typhoid-mortality being coincident with the
improvement made during the last twenty years in providing public
water-supplies. In the words of one of the State reports, "The
death-rate from typhoid fever has generally fallen as the per cent. of
the population supplied with public water has risen, for the reason
that the majority of the deaths from this disease have occurred among
communities and portions of communities _not supplied with public
water_."
That this improvement is being maintained is seen from the fact that
in the four-year period 1896-99 the deaths from typhoid fever in
Massachusetts were further reduced to 2·6 per 10,000.
It is, however, in the city of Lawrence that the most striking insight
is obtained as to the manner in which typhoid fever may be controlled
by conditions surrounding the water-supply to the community. Thus,
whereas the death-rate from typhoid fever reached a mean of 11·2 per
10,000 in 1886-90, it fell to 7·7 in 1891-95 and to 2·5 in 1896-99. It
was in the autumn of the year 1893 that the raw river-water supplied
to the city from the Merrimac River was first begun to be filtered,
and since that time the sand-filters have been subjected to systematic
and most elaborate bacterial supervision, and improvements have been
constantly introduced so as to secure the most efficient purification
possible of the water before distribution, and the results are
reflected in the marked diminution in typhoid fever which has followed
these strenuous efforts to obtain the best water-supply available.
The splendid example set by the State of Massachusetts, in promoting
the welfare of the people by the encouragement of original researches
in practical hygiene, has stimulated other American States to create
Boards of Health and enact laws for the protection of their rivers and
streams. In view of all that has been done to promote sanitary science
in the United States, it is surprising to learn that Lake Michigan,
which receives the untreated sewage of municipalities and small towns
aggregating over two million people, still furnishes Chicago with its
drinking water, and undergoes no preliminary purification before
distribution. The city of Chicago, by constructing the Chicago
Drainage and Ship Canal, opened in January, 1900, has diverted its own
sewage from Lake Michigan, but this great sewer has only been made
possible because of its advantages as a commercial waterway; and it
has been stated, on high authority, that every project for the
drainage of Chicago into the Illinois which has not recognised the
waterway features has been predestined to failure. Dr. Egan, of the
Illinois State Board of Health, however, points out that "with the
present increase in population the Great Lakes, if they continue to be
used as common sewers, will soon become totally unfit for use as
drinking water, ... and one of two alternatives must be
followed--either every source of water-supply must be filtered, or the
sewage of the towns must be efficiently purified before it is allowed
to flow into the lakes."
Doubtless this seeming inertia of the citizens of Chicago in the
matter of filtering their water is attributable to the fact that
already the authorities have expended eighty-five million dollars in
their waterworks and sewerage systems, which represents an investment
of something over fifty dollars per head of population, and that plans
in connection with the great canal which has been described as "the
greatest feat of sanitary engineering in the world," and to which
reference has already been made, will, when carried out, involve an
expenditure of thirty or forty million dollars more. In the face of
such burdens even so prosperous a community as Chicago does not care
to contemplate further capital charges, at any rate until the
unsatisfactory conditions shadowed by Dr. Egan become more pressing in
regard to the source of their water-supply.
The systematic investigations carried out in the great Institutes of
Health on the Continent and elsewhere should surely make the sporadic
work, as by comparison it must be designated, produced in this country
an eloquent argument for the creation of a British Imperial Board of
Health adequately endowed by the State, manned by the ablest
investigators, and forming a centre for the prosecution of researches
which in other countries, as in our own, have contributed so greatly
to the health and welfare of mankind.
Why should England for ever have to knock at the door of foreign
institutes for information and guidance in matters in which once she
was the leader and enlightened example to every civilised country?
The question of how far polluted water-supplies, besides possessing
the potentiality for spreading cholera and typhoid, may disseminate
consumption, has been approached in a very instructive manner by Dr.
Musehold, of the German Imperial Board of Health.
Some ten years ago the discovery of the tubercle bacillus in water for
the first time was announced by a Spanish investigator, Fernandez. The
water containing the bacillus tuberculosis was derived from an open
ditch, and hence had been doubtless exposed to contamination of divers
kinds.
In the course of the elaborate experiments on London sewage and its
treatment, carried out by Professor Frank Clowes, Chief Chemist to the
London County Council, an instance was recently met with in which a
guinea-pig, inoculated with a portion of coke-deposit derived from a
bacterial sewage bed, died from typical tuberculosis, and sections of
its organs showed the presence of numerous tubercle bacilli. Dr.
Musehold has now submitted the whole question of the vitality of
virulent tubercle bacilli present in the expectorations of consumptive
persons in sewage, in river water, and on cultivated land
respectively, to an exhaustive examination, and the novelty as well as
importance of these researches merit their being carefully considered.
In the first instance tuberculous sputum was introduced into river
water in its natural condition, and as this water was abstracted from
the River Spree, in Berlin, it was exposed at any rate to a certain
degree of surface contamination. In this water, kept in ordinary
daylight, the tubercle bacilli remained alive and in a virulent
condition for over five months; in ordinary sewage for six and a half
months. Some of the sewage-infected samples were left in the open air
and exposed to ordinary meteorological conditions, but even the ordeal
of getting frozen up in their surroundings did not in the slightest
shorten the lease of virulence possessed by the tubercle bacilli. Some
of this tubercle-infected sewage was poured over garden soil in which
radishes were growing, and after the bacilli had spent eighty-eight
days in these surroundings, during which time they had experienced
frost, snow, rain, and sunshine, they still retained their virulence.
Of special interest are the investigations Dr. Musehold made to
ascertain if tubercle bacilli could be detected on the fields attached
to a hospital for consumption and irrigated with the sewage from the
same. Not only were tubercle bacilli found, but they were also, as was
to be expected from the laboratory experiments cited above, discovered
in a highly virulent condition.
That disease germs may be distributed with the vegetables grown on
municipal sewage farms is not a mere whim or fancy of the faddist, but
is a very real danger, and must be regarded as a menace to the health
of all who consume such articles as lettuces, radishes, celery, and
other vegetables which are not first cooked before being placed on the
table.
This forcibly suggests the desirability of all expectorations from
consumptive patients being thoroughly disinfected, or, in other words,
deprived of their virulence before being admitted to sewage.
The importance of such precautions being taken is borne out by the
examinations of the clear effluent derived from the treatment of the
sewage of a consumptive hospital which revealed the presence of
virulent tubercle bacilli, whilst they were also discovered in the
bottom of a ditch conducting the effluent away.
Such facts as these deserve the earnest attention of all public
authorities, and it is to be hoped that the overwhelming evidence
which is now available regarding the distribution and Spartan
character of the tubercle bacillus will lead to serious efforts being
made to bestow upon it that measure of consideration which in the case
of recognised zymotic diseases leads to the enactment of rules and
regulations for the restriction at least of the fateful activities of
these malignant foes of mankind.
Before leaving the subject of bacteria in relation to water, it will
be interesting to glance at what is known regarding the attitude taken
up by these minute forms of life towards that large and
ever-increasing class of waters vaguely grouped together under the
synonym of mineral waters. The fortunes made in manufacturing
artificially aërated waters and the mine of wealth contained in a new
mineral spring are sufficient evidence of the popularity enjoyed by
this description of beverage. The beer and spirit statistics of the
country and their contributions to the national revenue do not,
however, permit us to indulge in the belief that this large
consumption of harmless drinks is due to their displacing the use of
intoxicants--the increasing sale of non-alcoholic beverages cannot in
fact be taken as an index of the growing sobriety of a nation; far
more must the greater demand be attributed to the improvements in
manufacture which have cheapened production and placed what was
formerly an article of luxury almost prohibitive in price, and hence
reserved for the few, within comparatively easy reach of the many.
Perhaps also an increased sale may be assisted by a prevailing
impression that by substituting carbonated for ordinary potable water,
the risk of contracting zymotic disease is, if not altogether removed,
at any rate very materially diminished.
It will be therefore instructive to see how far this assumption is
justified by actual facts.
The first fact to be recognised is that the number of bacteria present
may and does fluctuate between such wide limits as is represented by
as few as three, and as many as 100,000 being found in about twenty
drops of artificially aërated waters. Seltzer water, manufactured from
well water, was found by Sohnke to contain numbers varying from 200 to
6,000, whilst when only distilled water was used, _i.e._ water
previously deprived of all bacterial life, only from ten to thirty
microbes were present. But an important and far too little recognised
factor in the manufacture of aërated waters is the contamination which
so frequently takes place subsequent to the initial purification of
the water by sterilisation. In some instances this contamination is
due to the storing of water before use in reservoirs, where an
excellent opportunity is offered for microbial multiplication.