comma-bacillus of Koch; _a_, spirillum stage of growth, with vibrating
flagellum, by which it is driven along with screw-like movement; _b_,
the spirillum has lost its flagellum, and is motionless: it is marked
off into separate segments; _c_, the segments have separated from one
another as comma-shaped pieces, hence the name “comma-bacillus” given to
it by Koch; _d_, a number of comma-bacilli of cholera which have
developed tails of vibratile protoplasm (like a single cilium), and are
swimming about, being driven by the lashing of these tails; _e_, a
cubical packet of sarcina; _f_, a double row of the spherical units
(cocci or micrococci), which form a sarcina-packet; _g_, similar cocci
separated.]
The circumstances which determine whether the cholera-bacillus, when it
gets into the human intestine, will develop and cause an attack of
cholera, or will simply be digested or will remain alive, but inactive,
for a time, have yet to be exactly determined. Obviously a knowledge of
them must be of immense importance. Certain experiments show that other
minute parasitic organisms—especially those called _Sarcina_ (Fig. 46,
_e_), which often, but by no means always, are abundant in the human
intestine—favour the growth of the cholera-bacillus—in fact, prepare
the ground or soil, as we may call it, for that deadly organism. This
has been shown experimentally by sowing cholera-bacillus on plates of
slightly acid gelatine, or jelly. It will not grow on this, but if at
certain points on the surface of the jelly the _Sarcina_ organism is
planted, then it is found that all around the points where the _Sarcina_
is growing the cholera-bacillus also flourishes and multiplies. And it
seems probable that, just as there are microbes which are adjuvant or
helpful to the cholera microbe, so there are others which are repressive
or destructive of it. We know that this is the case with regard to some
other microbes—namely, that a microbe which will flourish abundantly on
a prepared jelly if it is alone, is entirely repressed and arrested in
its growth by the presence of one other ascertained kind. It is, in
fact, thus that some of the commoner putrefactive kinds of microbes
occurring in river water are repressive of the typhoid-bacillus, which,
if it should get there, flourishes best in the purest water or in water
containing no other microbe. There is some ground for thinking that in
certain districts there may be microbes present which make their way
into the human intestine, and then actually repress the
cholera-bacillus, should it subsequently be taken in with food or water.
It would, of course, be of immense importance to discover such a
microbe, if it exist, and the inquiry is at the present moment
proceeding in Paris.
A very striking and at first sight astonishing fact in regard to this
subject is that there are a very large number and variety of microbes
habitually present in the human digestive tract. There are so many
different kinds—differing altogether from one another in their chemical
action—which are present in greater or less abundance in this tract
from one end to the other, that no one is at present able to say even
approximately how many there are, nor to give anything like a complete
account of their properties. The fact is that their isolation and study,
and the definite determination of their properties, is not an easy job.
Many workers are engaged on it, and it will be years before the matter
is threshed out. One most curious result of these studies is that a
person may have the cholera-bacillus in his intestine—not growing with
any activity, but still alive—and yet be perfectly well. He can,
therefore, carry the cholera-bacillus from one locality to another and
spread the disease, and yet be entirely devoid of suspicion, free
himself from disease, and certified as healthy! The same is true of the
bacillus of typhoid fever. Persons who have had typhoid fever have been
shown to retain the typhoid-bacillus flourishing for as long as fourteen
years afterwards in their intestine, without any ill effects to
themselves, and to have been the constant source of infection and
disease to those living in the same house with them by spreading the
bacillus. The classical case of this is that of a woman who carried on a
baker’s business at Strasburg. Infection by and protection from microbes
is by no means so simple a thing as it is sometimes represented to be.
Now that we are quite sure as to Koch’s comma-bacillus, or spirillum,
being the definite poison-producing agent causing Indian cholera, it is
comparatively easy to understand its mode of dispersal and infection,
and consequently how to avoid its attack. It is cultivated in the
laboratories devoted to the study of such matters—kept in confinement,
so to speak, for ten years and more—and its properties and conditions
of life are well known. For instance, it is destroyed by “dryness,”
hence it cannot be carried in a living infective state as “dust” in the
air. It is also destroyed by exposure to a heat a good deal below that
of boiling water, so that water itself can be freed from it by boiling,
and food dipped in boiling (or nearly boiling) water, or heated on a
metal tray beneath which a spirit or gas flame is burning, can be
rendered safe just before it is swallowed, even when cholera is rife in
the neighbourhood. Ordinary lime is a great destroyer of the bacillus,
and can be used on a large scale to abolish it in refuse.
When the cholera is near one cannot be too scrupulously clean. The
fingers must be carefully washed with antiseptic before a meal, and
everything purified by heat only a few moments before being put into the
mouth, since flies and careless handling may soil food or anything else
exposed in a cool condition even for a few minutes. It is best when
cholera is actually present in the house or town in which you live to
swallow nothing which has been allowed to get cool; everything should be
heated and eaten when hot. Mephistopheles, in Goethe’s _Faust_,
complains of the swarming, pullulating life on the earth. He—the great
destroyer—says:
“How many have I sent to grass!
Yet young, fresh blood, do what I will
Keeps ever circulating still.
In water, in the earth, in air,
In wet, dry, cold—everywhere
Germs without number are unfurl’d,
And but for fire, and fire alone,
There would be nothing in the world
That I could truly call my own.”
The version is Sir Theodore Martin’s. Mephistopheles might be a
bacteriologist explaining the difficulty of dealing with disease germs.
In any case, it is the Mephistophelian spirit of annihilation, and flame
as its instrument, which man brings to his service in the contest with
cholera germs.
The great carriers of cholera are human beings themselves travelling in
caravans, pilgrimages, shiploads. For the fact has now been established
that a man may harbour inside him the cholera-bacillus without its
multiplying largely or rendering him seriously ill. Once it is brought
by such an individual into a favourable locality, it is spread by water
contaminated by him, and yet used for drink and domestic purposes; and
also it is spread by his touching things in which the bacillus can grow,
such as cooked food, fruits, etc., swallowed subsequently by
unsuspecting purchasers or employers. You have, in order to avoid
cholera (and similar infections), not only to have very clean fingers
yourself, but to see to it that your servants’ fingers are clean also,
or else that anything they touch is afterwards heated for a few minutes
to near boiling-point before you let it enter your mouth. A little
history illustrative of the need of this precaution is on record. In
Egypt during a recent outbreak of cholera there was a very wealthy lady
who lived alone in an isolated palace under the charge of a physician.
She had a delicate appetite; her food was most carefully prepared. She
drank and used only boiled sterilised water; no one was allowed to
approach her except her servants, who never left the palace grounds, and
were in good health. She sickened of cholera and died. It was a puzzle
as to how she had acquired the infection. Her physician at last
discovered that she daily partook of cold chicken-broth, prepared
carefully by her cook. The cook, though practically well, was found to
be infected with the cholera-bacillus, which had probably lodged in his
intestine some weeks previously at the commencement of the outbreak of
the disease in Egypt. Though living in him the cholera-bacilli had not
found a favourable field of growth. This man in handling the cold broth,
the cloth used to rub the spoon with which it was stirred, or the basin
itself, had, it was found by making the actual experiment, been able to
transfer the minute bacillus to the cold broth, a most favourable and
nourishing medium for its growth, and so his isolated carefully guarded
employer received an abundant crop of the bacilli and developed a fatal
attack of cholera. Had the lady taken the broth hot, there would have
been no living cholera-bacillus in it, and if she had thus guarded
herself in regard to all food, by the use of heat and great cleanliness,
she would have escaped infection.
The most interesting development of knowledge and speculation with
regard to the microbes which infest the human intestine and other
regions of the human body is (as I mentioned above) connected with the
fact that one kind or species of microbe has the power of favouring the
growth of another, if present alongside of it, and that another kind has
the power of checking or antagonising its growth. Thus common
putrefactive microbes of river water are hostile to the cholera-bacillus
and to the typhoid-bacillus. Those disease-producing bacilli live
longest and best in very pure water! Thus, too, it is found that the
microbe of sour milk—the lactic-bacillus—is antagonistic to the common
putrefactive microbe of the intestinal contents—the well-known bacillus
coli. In virtue of the acid which it produces, the microbe of sour milk
arrests the excessive growth and activity of the putrefactive bacillus
coli. Hence the utility of sour milk in many cases of intestinal
trouble. We contain within us a microbian flora of such variety and
abundance of kinds and so nicely balanced in their antagonisms and
co-operations in a healthy man, that one cannot wonder at the timidity
of the medical man who hesitates to interfere with their conflicts and
established _modus vivendi_. Yet that seems to be the direction in which
action will have to be taken. It seems likely that in different
localities—towns, forests, highlands, lowlands, seaboards—there are
prevalent different microbes which enter the bodies of human visitors
and act as disturbers of the native microbian flora previously
established in the stranger.
That there are great differences in the microbian flora (including
herein minute moulds and fungi as well as bacteria) of different
localities, is shown by the great experiment of cheese-making which
mankind carries on. Each kind of cheese—Stilton, Cheshire, Dutch,
Roquefort, Gruyère, Gorgonzola, etc.—is the result of the combined and
successive action on milk of a vast number of microbes; and it is the
fact that the combination which produces any given kind of cheese is
only found and (unconsciously of the exact nature of what he is doing)
brought into activity by man at certain places. You cannot make Cheshire
cheese in France nor Gruyère in Cheshire, and so on. It is
suggested—and the matter is being pursued by experiment and observation
at the present time in France—that possibly amongst the other things
which go to make up the qualities of the air which agrees or disagrees
with one in any given locality—are the local microbes. This must not be
regarded as a conclusion which has been fully worked out—it is an
ingenious and promising suggestion made by Metchnikoff as the result of
some observations, and will be fully inquired into. The fact which I
have mentioned above (p. 242)—that the presence of the microbe
_Sarcina_ favours the growth of the cholera-bacillus—indeed, enabling
it to grow and flourish in conditions in which it was inert until the
_Sarcina_ was “sown” alongside of it—renders it worth investigating
the question as to whether there are “local” germs or microbes which in
this or that region are abundant and get into man’s food and drink, and
so into his intestine, and become established there, helping or
antagonising the growth of other microbes already there or subsequently
introduced. Thus, to the various considerations in regard to the “air”
of a locality, such as rarefaction, moisture, temperature, movement,
ozone, and the perfumes and exhalations of pine trees, rosemary, and
sweet-smelling grasses, which seem to be those which are the most likely
to affect the health of inhabitants and visitors, it is not improbable
that we must add the influence of an invisible local flora of microbes.
The inquiry is a long and laborious one, but it will be carried through.
The microbes, whether in air or water, or on the surfaces of things, can
be collected by washing them into warm liquid gelatine. Then the
gelatine is poured out on a plate, and hardens as a thin sheet of jelly.
This is protected from all further contamination, and, after a few
hours, each invisible microbe embedded immovably in the jelly makes
itself apparent. It multiplies enormously whilst remaining stuck to one
spot, and is no longer invisible, but presents itself to the eye as a
little sphere, or disc, of characteristic shape, colour, and quality,
consisting of many hundred thousands of crowded microbes produced by the
growth and division of the original invisible one. Some dozens or some
hundreds of little growing “dots,” and of many various kinds, will thus
reveal themselves in the jelly according to the number and kinds of
utterly invisible parent microbes introduced by your “washings” into the
jelly. And so the investigator has the means of getting at each kind of
invisible microbe quite detached from the others, and of separating it
for further cultivation and experiment as to its chemical and
disease-producing qualities. These microbial gardens of jelly-plates
are, indeed, a wonderful revelation and a fitting “horticultural”
accompaniment to the dark and gloomy forests of rampant wild microbes in
our insides, where all are struggling for the soil, one crushing out
another by its sheer exuberance, a third choked by the encircling
luxuriance of a fourth, just as the trees, mosses, and climbers of a
tropical jungle are budding, pushing, grasping, destroying one another
in their irrepressible growth.
Pettenkofer, of Munich, when he found (as Metchnikoff did later) that
the cholera-bacillus could be swallowed in spoonfuls without producing
any harm, came to the conclusion that, though it was a necessary agent
of the disease “cholera,” yet that there was still an unknown additional
determining “cause” of a local character which must be present in order
to render the “cholera-bacillus” effective. Metchnikoff is now seeking
this “local” cause and parallel antagonistic causes, in the microbian
flora of localities which locally effect an entry into the human body,
and are, on the one hand, “favourable,” or on the other hand
“antagonistic.” Take as a concrete example Versailles. When cholera has
been rife in Paris, there has been no cholera at Versailles. There is
something at or about Versailles which does not permit cholera to
flourish in men who live there. The guess—the hypothesis—which is
being investigated at this moment, is that there is possibly a microbe
present at Versailles which enters into the microbial jungle of the
intestine of mankind there, and is inimical to, repressive of, the
cholera-bacillus when it also arrives there. Similarly, the suggestion
is entertained, and is being experimentally tested, that there is in
Paris a microbial inhabitant of the intestine which is favourable to the
energetic growth of the cholera-bacillus when it puts in an appearance,
but that this favouring (as yet undetermined) microbe does not exist at
Versailles.
These imaginings and guesses as to favouring and antagonising microbes
must not be confused with the definitely ascertained facts as to the
cholera-bacillus. But they are quite sufficiently important and probable
to justify their narration to a discreet and sympathetic public.
XXVI
SEA-BREEZES, MOUNTAIN AIR, AND OZONE
Fifty years ago people were very fond of talking about “ozone,” and the
word is popularly used nowadays to signify a mysterious attribute of the
air of the sea-coast or moorland without its real significance being
generally understood. When Sir Oliver Lodge the other day warned people
against hurting their nasal passages by sniffing up an unduly strong
dose of ozone produced by a special ozone-making apparatus, I am
inclined to think that most people who read what he said wondered what
“ozone” might be.
In the eighteenth century it was noticed that the sparks from a
frictional electrical machine are accompanied by a peculiar pungent
smell in the air. Many years after that, namely in 1840, the great
chemical experimenter, Schönbein, the friend and correspondent of
Faraday and discoverer of gun-cotton, found that the smell in question
is produced by a special gas, which is formed in the air when electric
discharges take place. He found that this gas was a powerful
oxydiser—would, in fact, oxydise iodide of potassium so as to set free
iodine—and thus its presence could be detected by means of paper slips
coated with a mixture of starch and iodide of potassium. When they were
exposed in air which contained even minute traces of this strange gas
they became purple-blue, owing to the liberation of iodine and the
formation of its well-known blue combination with the starch. Schönbein
found that in breezy, fresh places his test-papers turned blue, and
concluded from that (confirmed by other evidence) that this smelling
gas, to which he gave the name ozone—which simply means “the smelling
stuff”—is present in good, ordinary atmospheric air, as well as in
artificially “electrified” air. It is destroyed when such air is heated
above the boiling-point of water, and seems to be, as it were, “taken
out” of the air by all sorts of dead organic matter, so that it is not
present in the air of large cities. I remember that when I was a boy we
used to test the air for ozone with Schönbein’s papers (I am aware that
their colour change is not absolute proof of the presence of ozone, as
other oxydising gases might, if present, act in the same way), and we
used to find more ozone when a south-west wind was blowing than in a
north-easter!
Schönbein wrote sixty papers on ozone—but its real nature was made out
by others who succeeded him, chiefly by Andrews, of Belfast, and Tait,
of Edinburgh. It turns out that ozone is a condensed form of the
elemental gas oxygen—squeezed, as it were, and literally “intensified,”
so that three measures of oxygen gas become only two of ozone. It very
readily changes back again—two measures of ozone expanding to form
three of oxygen. It is produced by the action of an electric discharge
upon oxygen gas driven over the discharge and in greatest quantity when
that kind of gently-buzzing electric spark which is called “the silent
discharge” is used. It can be produced in quantity by passing
atmospheric air, or better, pure dry oxygen gas through a glass tube in
which such a silent discharge is made to take place. As much as
seventeen parts in a hundred of the gas can be thus converted into
“ozone,” and some twenty years ago two French chemists succeeded in
getting even a larger proportion, and by submitting it to a tremendous
pressure at a temperature of 100 degrees below the freezing-point of
water, they obtained pure ozone as a transparent liquid. It was of a
dark indigo-blue colour, and somewhat dangerous and explosive when the
pressure under which it had formed was removed. Ordinary oxygen gas has
since then been also liquefied in the laboratory: it is of a paler blue
colour.
The “smell” which old writers had noticed and Schönbein had named was
thus actually obtained as a distinct blue liquid. It is this which,
though present only in minute quantities, gives special oxydising
activity to fresh air. When pure, or present even to the small extent of
4 per cent. in air, ozone is a destructive agent, a sort of
extra-quality oxygen of triple instead of double power. Indiarubber is
rotted and destroyed by it in a few minutes—a sort of combustion or
quick oxydation taking place—and it is, of course, dangerous to the
softer parts of the human body, such as the air passages and lungs and
the eyes—when present in more than a minimal proportion. I believe that
no one has yet determined exactly how great a percentage of ozone can be
tolerated by a human being in the air taken into the lungs. In ordinary
fresh country or sea-coast air only one part by measure in 700,000 has
been found to be ozone, that is, 1/7000 per cent. But it is quite likely
that much more is occasionally present, since it is very difficult to
arrange a satisfactory examination of the air of any locality so as to
determine how much ozone it contains. It is said that at higher levels
the atmosphere contains more ozone than it does at lower levels.
It is not to be wondered at that ozone should thus have attracted
general attention and interest as the distinctive and specially active
agent present in the pure air of the sea-coast and the mountain-top.
People not infrequently, on arriving at the seaside, sniff up the
odours of decomposing seaweed (containing a little iodine), and think
they are smelling the “ozone.” It is doubtful whether enough ozone is
ever present in the atmosphere under simple natural conditions to affect
even a highly-sensitive nose. But it is easy to produce enough by
passing air over a silent electrical discharge to fill a large room with
its peculiar smell. Whether it really is of benefit to the human being
who inhales a properly limited percentage of it seems not to have been
clearly decided by experiment, although both in London and the United
States of America there are enterprising medical men who are convinced
of its value and are using it. It would certainly seem that if the
peculiar benefit which is often derived from sea air or from mountain
air is due to the presence of this extra oxygen in such air, then
nothing can be simpler or more rational than to introduce the proper and
useful percentage of ozone into the air of specially-arranged chambers
in London and other large towns, so that we can visit or even inhabit
them and breathe ozonised air at will without going on a journey for it.
But it is a remarkable fact that, as with various natural so-called
“mineral waters,” so with various “airs” which people find
beneficial—no one has yet clearly and decisively shown, in the first
place, whether they exert any chemical effect of a special kind on the
people who seem to benefit by drinking the one or breathing the other;
still less has any one shown what is the particular chemical ingredient
of the air or of the water of any given resort which exerts the
beneficial effect attributed to that air or that water.