THE TWO BREATHS.  A LECTURE DELIVERED AT WINCHESTER, MAY 31, 1869

Ladies,—I have been honoured by a second invitation to address you here, from the lady to whose public spirit the establishment of these lectures is due.  I dare not refuse it: because it gives me an opportunity of speaking on a matter, knowledge and ignorance about which may seriously affect your health and happiness, and that of the children with whom you may have to do.  I must apologize if I say many things which are well known to many persons in this room: they ought to be well known to all; and it is generally best to assume total ignorance in one’s hearers, and to begin from the beginning.

I shall try to be as simple as possible; to trouble you as little as possible with scientific terms; to be practical; and at the same time, if possible, interesting.

I should wish to call this lecture “The Two Breaths:” not merely “The Breath;” and for this reason: every time you breathe, you breathe two different breaths; you take in one, you give out another.  The composition of those two breaths is different.  Their effects are different.  The breath which has been breathed out must not be breathed in again.  To tell you why it must not would lead me into anatomical details, not quite in place here as yet: though the day will come, I trust, when every woman entrusted with the care of children will be expected to know something about them.  But this I may say—Those who habitually take in fresh breath will probably grow up large, strong, ruddy, cheerful, active, clear-headed, fit for their work.  Those who habitually take in the breath which has been breathed out by themselves, or any other living creature, will certainly grow up, if they grow up at all, small, weak, pale, nervous, depressed, unfit for work, and tempted continually to resort to stimulants, and become drunkards.

If you want to see how different the breath breathed out is from the breath taken in, you have only to try a somewhat cruel experiment, but one which people too often try upon themselves, their children, and their work-people.  If you take any small animal with lungs like your own—a mouse, for instance—and force it to breathe no air but what you have breathed already; if you put it in a close box, and while you take in breath from the outer air, send out your breath through a tube, into that box, the animal will soon faint; if you go on long with this process, it will die.

Take a second instance, which I beg to press most seriously on the notice of mothers, governesses, and nurses: If you allow a child to get into the habit of sleeping with its head under the bed-clothes, and thereby breathing its own breath over and over again, that child will assuredly grow pale, weak, and ill.  Medical men have cases on record of scrofula appearing in children previously healthy, which could only be accounted for from this habit, and which ceased when the habit stopped.  Let me again entreat your attention to this undoubted fact.

Take another instance, which is only too common: If you are in a crowded room, with plenty of fire and lights and company, doors and windows all shut tight, how often you feel faint—so faint, that you may require smelling-salts or some other stimulant.  The cause of your faintness is just the same as that of the mouse’s fainting in the box: you and your friends, and, as I shall show you presently, the fire and the candles likewise, having been all breathing each other’s breaths, over and over again, till the air has become unfit to support life.  You are doing your best to enact over again the Highland tragedy, of which Sir James Simpson tells in his lectures to the working-classes of Edinburgh, when at a Christmas meeting thirty-six persons danced all night in a small room with a low ceiling, keeping the doors and windows shut.  The atmosphere of the room was noxious beyond description; and the effect was, that seven of the party were soon after seized with typhus fever, of which two died.  You are inflicting on yourselves the torments of the poor dog, who is kept at the Grotto del Cane, near Naples, to be stupified, for the amusement of visitors, by the carbonic acid gas of the Grotto, and brought to life again by being dragged into the fresh air; nay, you are inflicting upon yourselves the torments of the famous Black Hole of Calcutta; and, if there was no chimney in the room, by which some fresh air could enter, the candles would soon burn blue—as they do, you know, when ghosts appear; your brains become disturbed; and you yourselves run the risk of becoming ghosts, and the candles of actually going out.

Of this last fact there is no doubt; for if, instead of putting a mouse into the box, you will put a lighted candle, and breathe into the tube, as before, however gently, you will in a short time put the candle out.

Now, how is this?  First, what is the difference between the breath you take in and the breath you give out?  And next, why has it a similar effect on animal life and a lighted candle?

The difference is this.  The breath which you take in is, or ought to be, pure air, composed, on the whole, of oxygen and nitrogen, with a minute portion of carbonic acid.

The breath which you give out is an impure air, to which has been added, among other matters which will not support life, an excess of carbonic acid.

That this is the fact you can prove for yourselves by a simple experiment.  Get a little lime water at the chemist’s, and breathe into it through a glass tube; your breath will at once make the lime-water milky.  The carbonic acid of your breath has laid hold of the lime, and made it visible as white carbonate of lime—in plain English, as common chalk.

Now, I do not wish, as I said, to load your memories with scientific terms: but I beseech you to remember at least these two—oxygen gas and carbonic acid gas; and to remember that, as surely as oxygen feeds the fire of life, so surely does carbonic acid put it out.

I say, “the fire of life.”  In that expression lies the answer to our second question: Why does our breath produce a similar effect upon the mouse and the lighted candle?  Every one of us is, as it were, a living fire.  Were we not, how could we be always warmer than the air outside us?  There is a process going on perpetually in each of us, similar to that by which coals are burnt in the fire, oil in a lamp, wax in a candle, and the earth itself in a volcano.  To keep each of those fires alight, oxygen is needed; and the products of combustion, as they are called, are more or less the same in each case—carbonic acid and steam.

These facts justify the expression I just made use of—which may have seemed to some of you fantastical—that the fire and the candles in the crowded room were breathing the same breath as you were.  It is but too true.  An average fire in the grate requires, to keep it burning, as much oxygen as several human beings do; each candle or lamp must have its share of oxygen likewise, and that a very considerable one; and an average gas-burner—pray attend to this, you who live in rooms lighted with gas—consumes as much oxygen as several candles.  All alike are making carbonic acid.  The carbonic acid of the fire happily escapes up the chimney in the smoke: but the carbonic acid from the human beings and the candles remains to poison the room, unless it be ventilated.

Now, I think you may understand one of the simplest, and yet most terrible, cases of want of ventilation—death by the fumes of charcoal.  A human being shut up in a room, of which every crack is closed, with a pan of burning charcoal, falls asleep, never to wake again.  His inward fire is competing with the fire of the charcoal for the oxygen of the room; both are making carbonic acid out of it: but the charcoal, being the stronger of the two, gets all the oxygen to itself, and leaves the human being nothing to inhale but the carbonic acid which it has made.  The human being, being the weaker, dies first: but the charcoal dies also.  When it has exhausted all the oxygen of the room, it cools, goes out, and is found in the morning half-consumed beside its victim.  If you put a giant or an elephant, I should conceive, into that room, instead of a human being, the case would be reversed for a time: the elephant would put out the burning charcoal by the carbonic acid from his mighty lungs; and then, when he had exhausted all the air in the room, die likewise of his own carbonic acid.

* * * * *

Now, I think, we may see what ventilation means, and why it is needed.

Ventilation means simply letting out the foul air, and letting in the fresh air; letting out the air which has been breathed by men or by candles, and letting in the air which has not.  To understand how to do that, we must remember a most simple chemical law, that a gas as it is warmed expands, and therefore becomes lighter; as it cools, it contracts, and becomes heavier.

Now the carbonic acid in the breath which comes out of our mouth is warm, lighter than the air, and rises to the ceiling; and therefore in any unventilated room full of people, there is a layer of foul air along the ceiling.  You might soon test that for yourselves, if you could mount a ladder and put your heads there aloft.  You do test it for yourselves when you sit in the galleries of churches and theatres, where the air is palpably more foul, and therefore more injurious, than down below.

Where, again, work-people are employed in a crowded house of many storeys, the health of those who work on the upper floors always suffers most.

In the old monkey-house of the Zoological Gardens, when the cages were on the old plan, tier upon tier, the poor little fellows in the uppermost tier—so I have been told—always died first of the monkey’s constitutional complaint, consumption, simply from breathing the warm breath of their friends below.  But since the cages have been altered, and made to range side by side from top to bottom, consumption—I understand—has vastly diminished among them.

The first question in ventilation, therefore, is to get this carbonic acid safe out of the room, while it is warm and light and close to the ceiling; for if you do not, this happens—The carbonic acid gas cools and becomes heavier; for carbonic acid, at the same temperature as common air, is so much heavier than common air, that you may actually—if you are handy enough—turn it from one vessel to another, and pour out for your enemy a glass of invisible poison.  So down to the floor this heavy carbonic acid comes, and lies along it, just as it lies often in the bottom of old wells, or old brewers’ vats, as a stratum of poison, killing occasionally the men who descend into it.  Hence, as foolish a practice as I know is that of sleeping on the floor; for towards the small hours, when the room gets cold, the sleeper on the floor is breathing carbonic acid.

And here one word to those ladies who interest themselves with the poor.  The poor are too apt in times of distress to pawn their bedsteads and keep their beds.  Never, if you have influence, let that happen.  Keep the bedstead, whatever else may go, to save the sleeper from the carbonic acid on the floor.

How, then, shall we get rid of the foul air at the top of the room?  After all that has been written and tried on ventilation, I know no simpler method than putting into the chimney one of Arnott’s ventilators, which may be bought and fixed for a few shillings; always remembering that it must be fixed into the chimney as near the ceiling as possible.  I can speak of these ventilators from twenty-five years’ experience.  Living in a house with low ceilings, liable to become overcharged with carbonic acid, which produces sleepiness in the evening, I have found that these ventilators keep the air fresh and pure; and I consider the presence of one of these ventilators in a room more valuable than three or four feet additional height of ceiling.  I have found, too, that their working proves how necessary they are, from this simple fact:—You would suppose that, as the ventilator opens freely into the chimney, the smoke would be blown down through it in high winds, and blacken the ceiling: but this is just what does not happen.  If the ventilator be at all properly poised, so as to shut with a violent gust of wind, it will at all other moments keep itself permanently open; proving thereby that there is an up-draught of heated air continually escaping from the ceiling up the chimney.  Another very simple method of ventilation is employed in those excellent cottages which Her Majesty has built for her labourers round Windsor.  Over each door a sheet of perforated zinc, some 18 inches square, is fixed; allowing the foul air to escape into the passage; and in the ceiling of the passage a similar sheet of zinc, allowing it to escape into the roof.  Fresh air, meanwhile, should be obtained from outside, by piercing the windows, or otherwise.  And here let me give one hint to all builders of houses.  If possible, let bedroom windows open at the top as well as at the bottom.

Let me impress the necessity of using some such contrivances, not only on parents and educators, but on those who employ work-people, and above all on those who employ young women in shops or in work-rooms.  What their condition may be in this city I know not; but most painful it has been to me in other places, when passing through warehouses or work-rooms, to see the pale, sodden, and, as the French would say “etiolated” countenances of the girls who were passing the greater part of the day in them; and painful, also, to breathe an atmosphere of which habit had, alas! made them unconscious, but which to one coming out of the open air was altogether noxious, and shocking also; for it was fostering the seeds of death, not only in the present but in future generations.

Why should this be?  Every one will agree that good ventilation is necessary in a hospital, because people cannot get well without fresh air.  Do they not see that by the same reasoning good ventilation is necessary everywhere, because people cannot remain well without fresh air?  Let me entreat those who employ women in work-rooms, if they have no time to read through such books as Dr. Andrew Combe’s ‘Physiology applied to Health and Education,’ and Madame de Wahl’s ‘Practical Hints on the Moral, Mental, and Physical Training of Girls,’ to procure certain tracts published by Messrs. Jarrold, Paternoster Row, for the Ladies’ Sanitary Association; especially one which bears on this subject, ‘The Black-Hole in our own Bedrooms;’ Dr. Lankester’s ‘School Manual of Health;’ or a manual on ventilation, published by the Metropolitan Working Classes Association for the Improvement of Public Health.

I look forward—I say it openly—to some period of higher civilisation, when the Acts of Parliament for the ventilation of factories and workshops shall be largely extended, and made far more stringent; when officers of public health shall be empowered to enforce the ventilation of every room in which persons are employed for hire; and empowered also to demand a proper system of ventilation for every new house, whether in country or in town.  To that, I believe, we must come: but I had sooner far see these improvements carried out, as befits the citizens of a free country, in the spirit of the Gospel rather than in that of the Law; carried out, not compulsorily and from fear of fines, but voluntarily, from a sense of duty, honour, and humanity.  I appeal, therefore, to the good feeling of all whom it may concern, whether the health of those whom they employ, and therefore the supply of fresh air which they absolutely need, are not matters for which they are not, more or less, responsible to their country and their God.

And if any excellent person of the old school should answer me—“Why make all this fuss about ventilation?  Our forefathers got on very well without it”—I must answer that, begging their pardons, our ancestors did nothing of the kind.  Our ancestors got on usually very ill in these matters: and when they got on well, it was because they had good ventilation in spite of themselves.