in four particulars, namely, as to whether it is still or windy, whether
it is cool or hot relatively to the local surface, whether it is heavy
or rarefied, whether it is dry or saturated with moisture. It is also an
important fact that the atmosphere consists of layers and currents
differing in these qualities, and that the higher layers can be reached
by ascending to high-lying lands. At the same time it seems that in a
flat country the ascent of a comparatively low hill brings you into a
layer or “stratum” of air differing more from that of the plain or
valley than would be the case were you to ascend to the same height in a
mountainous region. The seaside and the mountain may owe the beneficial
character of their air to some of the varying qualities noted above.
Chemical differences may or may not be important, and seem hardly to
have been as yet brought within the range of accurate knowledge. Ozone
may be more or less present, so may perfumes and volatile oils, such as
are given off by pine trees, and there may be more or less minute
quantities of carbonic acid and of sulphurous acid, and still minuter
quantities of the newly-discovered gases—argon and helium—which, for
all we know, may have some effect on the human body. There seems to be a
great field open for accurate investigations in regard to the action
upon human health of all these varying conditions of the air. In the
meantime, we proceed by guesswork, and are influenced by tradition and
beliefs which are based on a sort of experience, but are of a very vague
and unsatisfactory description.
The case is much the same with regard to the natural waters of
celebrated resorts. So far as their chemical composition is known, they
can be manufactured and applied for drinking or bathing anywhere. But
minute quantities of certain gases and other elements may be present in
these natural waters and have escaped until now the observation of the
chemist, and it is possible, though not demonstrated, that these rare
chemical constituents may have some action on those who drink or bathe
in the water. Ever since the time of the Romans natural mineral waters
have been sought, and the springs which discharge them have been
frequented, not because their chemical composition was known, but
because experience seemed to show that they produced a beneficial
result. It can hardly be doubted that the baths and springs frequented
at the present day are not so much themselves the cause of the benefit
to the cure-seekers as are the change of scene and diet, and the repose
and regular life willingly accepted by those who travel so far to reach
these springs.
With regard to ozone, there remains something more to be said, namely,
in regard to its application, in a far less diluted form than is
possible when it is taken into the lungs, to the destruction of
putrefying organic matter and putrefactive and disease-producing
bacteria. It is now some five or six years since air containing a high
percentage of ozone—produced by the action of the electric
discharge—was used for the purification of the water-supply of large
towns. It is a fact that river water into which such ozone containing
air is pumped becomes pure in the highest degree, in consequence of the
destruction by the ozone’s oxydising action, both of the bacterial germs
always present in vast numbers in river water and of the organic matter
on which the bacteria depend. This application of ozone is in use in
several large towns for the purification of drinking-water, for which
purpose it has very great advantages. It has also been successfully used
by Dr. Allen, the director of the Plymouth Marine Laboratory, for
keeping the water of the marine aquarium there in a state of purity and
well charged with oxygen gas. A similar use has been made of oxygen
containing a considerable percentage of ozone by enterprising surgeons
for the cleansing of ulcer and abscess. It is clear that such a gas may
present mechanical advantages over any liquid application.
Ozone is not, apparently, in favour or fashion with the general body of
medical practitioners at the present day, but possibly further
examination and determination of its physiological properties may lead
to its receiving more attention in medicine. Already the peroxide of
hydrogen—which is more or less correctly described as “ozonised water,”
and is used (under the name “Auricomous hair-wash”) to change dark hair
by its oxydising action to a golden tint—is used by surgeons for
washing out purulent wounds and abscess. Those who use the gas itself
only go a step further. Some day we may see a more general use of ozone;
on the other hand, it remains to be seen by direct and accurate
experiment whether its properties are as valuable to man as we may hope
they will prove to be.
XXVII
OXYGEN GAS FOR ATHLETES AND OTHERS
Since the preceding chapter on ozone was written I have learned that
this peculiar triple-condensed variety of oxygen (it is called by
chemists “O_{3}” whereas ordinary oxygen is “O_{2}”) is now being most
successfully applied to the purification of the water-supply of several
large cities. A notable case is that of the great winter resort, Nice.
Ozone gas is one of the most effective destroyers of organic impurity
known; it destroys both bacterial germs and the putrescible impurities
of water completely, and is itself converted in the process into
harmless health-giving oxygen, whilst the water is rendered absolutely
free of all germs. It is readily manufactured by treating oxygen with
the electric discharge, and is produced at a cost which renders its use
in water-purification an economical and financially satisfactory method.
The use of ozone gas as a medicinal application to cavities in the
living body in which disease-producing bacteria are lodged is making
progress. It has to be administered with great care by a medical expert,
and though there has been delay and opposition on account of the novelty
of the treatment, there are signs that ozone will become established as
a valuable therapeutic agent. It is a singular fact that so little has
been done of late by scientific observers either as to the presence of
ozone in the atmosphere or as to the action of ozone on the healthy
animal body when present in minute quantity in the air taken into the
lungs. The general opinion appears to be that it is either altogether
absent from the atmosphere or present only in quantity so minute as to
be negligible from the point of view of the physiologist except in very
high mountain regions, and there the exact quantity remains
undetermined. The only experiments in the last ten years on the subject
of its action on animals are some which led the inquirers to the
conclusion that constant exposure (in a closed chamber) to an atmosphere
containing 4 per cent. of ozone caused death after five or six days by
an inflammation of the lungs. Clearly it is desirable that further
investigation on this subject by competent authorities should be made,
and the effect of smaller quantities of ozone in the air respired,
whether continuously or at intervals, should be ascertained.
The action of ordinary oxygen gas is a separate matter. The atmosphere
which we breathe consists of one part by volume of this gas and of four
parts of nitrogen gas. It is the oxygen which is necessary to us and to
all animals, and the nitrogen is merely an inert diluting accompaniment
of the essential oxygen gas. It is, of course, easy to increase or to
diminish the proportion of oxygen in the air breathed accordingly as one
introduces additional pure oxygen or, on the other hand, diluting
nitrogen into a collapsible bag or sac from which one continuously draws
breath. Such a bag can be connected by a tube to a helmet or mask
enveloping the head. The expired air is discharged by a specially
provided passage. It used to be thought that it was dangerous to breathe
pure undiluted oxygen, although the proportion of oxygen to nitrogen in
the air taken into the lungs might be increased to as much as a half
without injury, and, indeed, with great benefit in some serious
conditions of collapse. Dr. Leonard Hill, F.R.S., of the London Hospital
Medical College, has, however, recently shown that oxygen gas, of 97 per
cent. purity, may be breathed continuously for as much as two hours
without any ill-effects or sense of inconvenience. Contrary to what has
been stated, it is neither exciting nor unpleasant. He has made the
experiment on himself and on some of his assistants, and in doing so has
made use of such an apparatus as that above-mentioned—so as to ensure
the in-take of undiluted oxygen.
Dr. Hill and Mr. Martin Flack have further found that the exhaustion and
labouring of the heart which is brought on by such special exertion as
that involved in running a hundred yards race or a quarter-mile race, is
almost completely avoided if the runner “fills his lungs” with oxygen
gas before starting. The runner takes the oxygen gas into the lungs for
some two or three minutes before starting to race; of course, the lungs
are not thus actually “filled” with oxygen, but a much larger proportion
of that gas is lodged in them than when ordinary air is breathed, and a
full supply is thus afforded to the blood. The “distress” caused by
violent athletic efforts appears to be entirely due to the using up of
the available oxygen by the unusual activity of the muscles. The heart
itself suffers most, the breathing becomes laboured, and there is a
sense of suffocation, due simply to the urgent demand by the blood,
heart and muscles for more oxygen. If, therefore, we ensure that there
is an extra supply of pure oxygen in the lungs before the unusual effort
is made, we avert these distressing symptoms: the unusual quantity of
oxygen needed is ready for use. Dr. Hill himself and young men who have
tried the plan of inspiration of oxygen before a foot-race, declare
that they cannot believe that they are really running hard, even when
surpassing their usual performance. They come in at the end of the
quarter-mile, having beaten their record; and with no sense of having
made a special effort; they feel fresh and ready to start again after
more oxygen and a short rest. Moreover, the after-effect on the muscles
is stated to be such that “stiffness” and what is called “grogginess”
(due in ordinary circumstances to the retention of lactic acid in the
muscle) do not supervene.
Swimming and diving, as one would expect, are greatly affected by the
preliminary oxygen inhalation; the length of time during which
submersion can be endured without discomfort is doubled, and the great
effort of fast swimming rendered less rapidly exhausting. Cycling uphill
at a rapid pace becomes, according to Dr. Hill’s own frequent
experience, possible after oxygen inhalation when in ordinary conditions
it was impossible. Hockey players and boxers he has found notably
benefited by oxygen given both in the intervals of and after the
exercise. It is, of course, to be expected that a wider practical
application should be made of this simple method of increasing our power
of sustaining muscular effort, and of enduring submersion. Dr. Hill
suggests that the divers of the Mediterranean, who, without any
apparatus, plunge into the shallow sea and remain below long enough to
find, cut, and bring to the surface the valuable sponges of commerce,
might use the method of preliminary inhalation of pure oxygen gas. He
has also tried the method with a young racehorse, but owing to the fact
that the course run was only a mile, and the animal perfectly fit and
strong, he tells me that no advantage was found to result from the
inhalation. With an older cart-horse somewhat tired by a day’s work—he
obtained the most satisfactory results, the animal becoming obviously
recuperated and working without distress.
The question has been raised as to whether the administration of oxygen
gas to a man or to a horse when about to run a race should be considered
as “doping.” It may perhaps be objected to by sportsmen, as involving
the provision of special apparatus which all competitors would not be
equally able to secure. But it is not “doping,” since that applies to
the use of a drug, which, whilst exciting to violent effort, produces an
injurious after-effect. Oxygen is not in this category; to take an extra
quantity of oxygen into the lungs before starting on a race is no more
unnatural or risky than to take an extra drink of water into the stomach
or to swallow meat extract and such special preparations before or
during a race. It would be interesting to see whether a runner in the
Marathon race would (as Dr. Hill would expect) be greatly assisted if
his trainer carried with him a supply of pure oxygen, and from time to
time refreshed him with it. Football players might also be given oxygen
at half-time; an oxygenated team would, one surmises, beat its
uninspired competitors. A Fife team is reported to have done so. On the
roads favoured by cyclists one may expect hereafter to find at the
bottom of a long ascent hawkers of “breaths of oxygen” provided with
gas-bags and calling out “Buy the lady a breff, sir!” It is, perhaps,
worth noting that the relief afforded by oxygen-breathing is no less
definite when the gas is taken immediately after a race or sustained
effort than when used as a preliminary. The excess of choke-gas or
carbonic acid formed during great muscular effort is not the principal
cause of the distress experienced. That gas is thrown off by increased
expiration. It is the using up of the oxygen and the insufficiency of
the supply in the atmospheric air inspired that causes, under these
circumstances, giddiness, exhaustion, and often collapse.
The difficulty in breathing and the prostration experienced by many
people in mountain-climbing is largely due, not merely to the muscular
effort of climbing, but to the fact that the rarefied atmosphere at
heights of 8000 ft. to 15,000 ft. and more gives into the lungs in every
inspiration but a fraction of the oxygen which is inspired at low
levels, and moreover, owing to the low pressure, much less is held in
the blood. Even when conveyed by mule, cog-rail, or balloon to these
heights—and, therefore, without muscular exertion, sensitive people
suffer severely from temporary “oxygen-starvation.” They as well as the
laborious mountaineer could be saved from all such inconvenience by the
use of a skilfully-constructed “traveller’s flask” of oxygen gas.
The observations and experiments as to the possible use of pure oxygen
by athletes suggest that we might all benefit by occasional if not
frequent use of such an atmosphere. Indeed, there are some
individuals—amongst others a well-known and distinguished actor—who
before making some special effort, or even when feeling tired and
unequal to their daily work, inhale under medical supervision a certain
quantity of oxygen gas. It would certainly seem that since country air,
sea air, and mountain air are useful and refreshing, an artificial
supply of extra oxygen might be inhaled in London, either in one’s own
house or in establishments provided for the purpose, with definite
benefit to health, especially if the inhalation were combined with
exercise.
The experiments made by Dr. Hill have come about in connection with work
undertaken for the purpose of improving the diving and life-saving
apparatus named after its inventor, Fleuss. This invention consists
essentially in a water-tight helmet and jacket connected with a
cylinder of compressed oxygen gas which is carried by the diver. The
advantage of such an arrangement is that the diver is free from pumping
apparatus and can go where an ordinary diver could not. Mr. Fleuss was
able, by diving with this apparatus, to prevent an immense loss of
property by arresting the flooding of the Severn tunnel which was
imminent during its construction. A difficulty in regard to the Fleuss
apparatus has been that oxygen gas is a poison, causing inflammation of
the lungs and convulsions when under a pressure of from two to three
atmospheres—that is to say, at from 30 ft. to 60 ft. depth in water.
The pressure exercised by the air of the atmosphere at sea-level is
equal to that exercised by a column of water 30 ft. high, and hence at
30 ft. depth in the sea the oxygen gas would be under the pressure both
of the atmosphere itself and of water to the same amount—which is
expressed by saying that it is under two atmospheres’ pressure, or twice
the atmosphere’s pressure. The pressure of the atmosphere is, in plain
figures, 15 lb. on every square inch of surface. Of course, the oxygen
is compressed far beyond this point in the cylinders in which it is
carried. In using it, it is allowed to escape by opening a valve leading
into an elastic sac, and is then and there subject to the pressure
depending on the depth of water to which the diver has descended. It is
found to be dangerous for a diver with this apparatus to descend to a
depth of more than 30 ft. having pure oxygen in his apparatus, because
the oxygen is then compressed under a pressure of two atmospheres.
Accordingly, Dr. Haldane, of Oxford, has proposed that the oxygen should
be diluted with atmospheric air, so as to give a mixture of equal
volumes of oxygen and nitrogen. With this mixture the diver can safely
descend to a depth of 60 ft. The apparatus is provided with a partition
containing caustic soda, which absorbs the carbonic gas thrown out of
the lungs in expiration. With such an apparatus a diver can safely
remain under water at a depth of 60 ft., and walk about and explore for
as long as two hours. A most important application of this
self-contained diving apparatus is found in its use in the exploration
of mines, where smoke or gaseous products resulting from an explosion
render it impossible for rescue parties to penetrate without its use. It
has been the means of saving many lives in such circumstances. A form of
this apparatus is made in which the oxygen is supplied, not by a
cylinder of compressed gas, but by granules of a chemical compound
called pneumatogen, a peroxide of sodium and potassium, which when
breathed into absorbs carbonic acid from the air expired by the lungs,
and gives off pure oxygen. Submarine ships are now being provided with a
dress or outfit of this description for each member of the crew, so that
in the case of the entrance of water into the submarine, every man can
put on his “oxygen helmet,” and one by one, when the ship is full of
water, they can pass out by the conning tower and float to the surface.
The perfected diving dress, with self-contained diluted oxygen supply
and other improvements, has been constructed by Siebe, Gorman, and Co.,
and was exhibited by Dr. Leonard Hill at a soiree of the Royal Society.
XXVIII
SPARROWS, TROUT, AND SELECTIVE BREEDING
The talk about the urgent need for the destruction of sparrows reminds
me that the word “sparrow” is applied commonly in this country to at
least two very different but common birds. No doubt farmers and
gardeners know well enough the house-sparrow (_Passer domesticus_ or
_Fringilla domestica_ of Linnæus), which is the one they consider
injurious. But some boys and some newly-fledged proprietors of country
places may inadvertently confuse the house-sparrow with a very different
bird, though only a little smaller and of a general brown colouring,
also called “sparrow,” namely, the hedge-sparrow (_Accentor modularis_).
The hedge-sparrow is a true denizen of the country. It does not live on
grain, but on insects and grubs, and is useful on that account to
agriculturists. Its eggs are pure blue. A spotted egg of a cuckoo laid
amongst them readily catches the eye, so that cuckoos’ eggs are often
found in hedge-sparrows’ nests. It seems that it is all a mistake on the
part of the cuckoo hen when this occurs. The strain of cuckoos properly
attached to hedge-sparrows lay a beautiful blue egg differing only in
its somewhat larger size from those of the hedge-sparrow itself, and
hence difficult to detect. These blue cuckoo-eggs—proper to cuckoos
which make use of the hedge-sparrow as foster-mother—escape detection
both by boys and the foster-parents, and successfully hatch out and
propagate the race of blue-egged cuckoos with a memory and a sense of
smell which bring them back if they are hen-birds to the little
hedge-sparrow’s nest when they are grown up and have an egg to dispose
of. The spotted grey or brownish eggs are, if not discovered by boys,
ejected (there is reason to believe) by the hedge-sparrows themselves.
They were deposited by mistake by some pippet-loving or warbler-seeking
strain of cuckoo in a hurry, or are throw-backs to a common ancestral
colouring of the egg due, perhaps, to the male parent not being of the
true blue strain. A very fine series of “clutches” and nests of
hedge-sparrow, robin, shrike, reed-warbler, pippet, yellow-hammer, and
other birds with the accompanying cuckoo’s egg may be seen in the
Natural History Museum, and they show how closely the parasitic egg
often resembles that of the foster-parent, though striking failures also
occur.
The hedge-sparrow is placed in that group of small birds which includes
the robin, the thrushes, and the warblers; it is not a finch. On the
other hand, the house-sparrow is a finch, allied to the chaffinch, the
goldfinch, and the brambling. It has, like all the finches, a very
powerful broad-based beak, and is more than a match for bigger birds
than itself. It is really a parasite or “commensal” (messmate) of man,
living and flourishing entirely by helping itself to the grain and the
young buds of shrubs grown by man, and in towns to the waste fragments
of his food and the grain left in horse-dung. Whether it does any good
in the early part of the year by eating grubs seems to be doubtful, but
the conclusion is justified that it does more harm than good, especially
as it drives away other small birds which are exclusively insectivorous.
It has gone with European man to all temperate climates. There are
Spanish, African, Italian and Indian species, closely related to the
common house-sparrow, which I should like to see put out side by side
with it and some of its varieties for the public edification in the
Natural History Museum. These are the true “sparrows,” and should be
compared side by side with the hedge-sparrow, and the differences
pointed out.
There is another true sparrow in England, called the “tree-sparrow,”
which is not nearly so common as the house-sparrow. They are, however,
so closely allied to one another that hybrids have been produced between
the two. On the other hand, the hedge-sparrow is a great deal too remote
from the finches to interbreed with the house-sparrow or any other of
the finch group.
There ought to be a careful report on the probable effects, in every
direction, of a great destruction of house-sparrows before any very
drastic measures are taken in that direction. The employers of
gamekeepers should remember that by destroying owls, hawks, and weasels
they may not only enable small injurious birds to flourish in excess,
but that they may encourage disease and weakness in the game-birds which
they so eagerly desire to multiply, since the natural extermination of
weakly birds by birds and animals of prey is put an end to when the
latter are abolished. In all such matters more knowledge is needed, and
reasonable people will not take irretrievable action until they have
taken the trouble to obtain thorough knowledge.
It is a curious fact that though the house-sparrow does not naturally
sing, yet hand-reared house-sparrows have been made, by association with
bull-finches, to acquire the song of that bird—a truly astonishing
instance of hidden or latent capacity.