Popular Science Monthly/Volume 40/April 1892/Bad Air and Bad Health I

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THE purpose of this paper is to utter a warning against the careless way in which the great mass of people, poor and rich, ignorant and learned, allow the air of their living-rooms to be in an impure condition, and to point out the great sacrifice of energy and health which results from this carelessness. We shall try to show that there is strong ground for believing that not only a large part of the ever-increasing trouble of bronchial and lung affections, but also a very large part of that vague and subtle ill-health which troubles our modern lives in varying forms, is to be placed to the account of the impure air which we so habitually breathe.

As we wish to make the paper plain to every one, we shall occasionally go back to the A B C of certain matters involved. The air which we breathe is made up of two gases, one active, one indifferent. The active gas, oxygen, on which life depends, is in the proportion of about one fifth (twenty-one per cent) of the whole; the indifferent gas, nitrogen, which tempers and dilutes its active partner, is in the proportion of four fifths (seventy-nine per cent), and with these two gases is found a small quantity—varying according to the purity of the air—of carbonic acid, about three to four parts in 10,000 parts, or 0·04 per cent, and in addition a minute quantity of a peculiarly active form of oxygen. called ozone, which is rarely found in the air of towns. Of this gas-mixture (which we call air) we breathe enormous quantities. Of it we breathe in the twenty-four hours, according to Prof. M. Foster, over 2,600 gallons, that is about 425 cubic feet; and as it returns from our lungs the proportions of the mixture are changed, the oxygen being reduced, and the carbonic acid increased.[1] But in all ordinary cases the quantity of oxygen in a room in which people are meeting is only slightly decreased, while the increase of the carbonic acid is not sufficient to cause bad effects. How, then, arises the mischief?

The truth is that, in taking air into the lungs and breathing it out again, we breathe out with it certain organic poisons. About the existence and presence of these poisons there can be no doubt, though very little is known about their nature. Of them Dr. Foster writes (page 552) that they may be formed in the lungs, or may be products of putrefactive decomposition allied to a class of poisons known as ptomaines, which are found in the system. Dr. A. Ransome (Health Lectures, 1875-76, page 160) says:

The aqueous vapor arising from the breath, and from the general surface of the body, contains a minute proportion of animal refuse matter, which has been proved, by actual experiment, to be a deadly poison. . . . It is this substance that gives the peculiar, close, unpleasant smell which is perceived on leaving the fresh air and entering a confined space occupied by human beings or other animals,. . . and air thus charged has been fully proved to be the great cause of scrofulous or tubercular diseases, and it is the home and nourisher of those subtle microscopic forms of life that have lately become so well known under the title of germs of disease, or microzyms. It is probably the source of a large part of that increase of mortality that seems inevitably to follow the crowding together of the inhabitants of towns.

Galton says (Our Homes, page 497): "This organic matter (given off from the lungs), on an average, may be estimated at thirty or forty grains a day for each adult";[2] and both Dr. Carpenter and Sir Douglas Galton notice that if breath be passed through water (and then kept in a closed vessel at a high temperature), putrefaction is set up, and a very offensive smell is given off.[3]

Now let us take the case of a person who sits in a closely shut up room, ten feet high, ten feet broad, and fifteen feet long, for five hours.[4] At the end of that time he is breathing air which contains 1·2 per cent less oxygen than it ought to contain, but, what is far more serious, he is breathing some air which has already passed through his lungs, and which is charged with this special poison. Here is the great secret of the fatal mischief. Nature has got rid of the poison, thrown it out of the system, but the perverse occupant of the room insists on thwarting Nature, and, by means of his closed doors and windows, breathes in again, it may be a second time or a third time, the poison that has once been safely got rid of. Say that in twenty-four hours 500 cubic feet have passed once through the lungs, then in six hours our friend will have vitiated one quarter of that quantity, or 125 cubic feet—i. e., one twelfth of the whole air in the room (1,500 cubic feet). If he still goes on sitting in his study, at the end of nine hours he will have vitiated 187·5 cubic feet, or one eighth of the whole; or, if he has been unfortunate enough to have a friend sitting with him, then in six hours they will have tainted one sixth of the air; and of every mouthful of air they breathe after that time, one sixth of it must be supposed to be charged with poisons that have been already once got rid of, but are now being retaken into the system. Of course, this proportion of one sixth will not remain constant. Each breath expired will make the matter worse.

A few words seem necessary here for those who have never followed the changes going on in the body. We know that we are constantly building up new tissue of different kinds, and that this building up makes it necessary that the old tissue should be got rid of. The larger part of our food measures this change which is going on. If we take our daily food, liquid and solid, for twenty-four hours, as weighing about five pounds eight ounces (Hermann, page 233)—a large proportion being water—we may look upon about five pounds three ounces of this quantity as used for the making of new tissue, the other five ounces forming what is spoken of as exhausted ferments, and which, passing along the alimentary canal, is eventually rejected. Now, all the suitable part of the food, after undergoing various changes, which are necessary to prepare it for its passage from dead food into living tissue, finds its way into the blood; and when by means of the larger blood-vessels it reaches the very minute blood-vessels, called capillaries, it pours a part of itself out through the permeable walls of these minute vessels, bathing and feeding the whole surrounding tissue. Thus, as somebody has said, the whole of the new and living body is in solution in this wonderful food-stream of the blood, which, by a very subtle mechanism of nerves, distributes its good gifts in proportion to the needs of each separate part. But the blood is not simply a food-stream, it is also a sewage-stream, and it is as such that we are specially interested in it. Where no growth or storing of flesh material of any kind is taking place in the system, it is evident that that part of the daily food which is turned into tissue measures not only the daily construction that is taking place within us, but also the daily destruction or waste. In fact we—if we may so speak of the particles of which we are composed—are forever living and dying within ourselves—making a new self, and getting rid of an old self; and just as the new living body is in solution in the blood, so also is the old dead body, that has done its work and has to be got rid of. Now, of this dead body a large part has to escape through our lungs and through our skin.

About this process of waste very little is known. We know, while certain temporary forms of waste are found in muscle, such as kreatin (Gr. Kreas, flesh), which, whether again made use of or not (M. Foster, page 154), is supposed to be eventually changed in some complex manner into urea in the liver (M. Foster, page 755), and an acid called sarcolactic (Gr. sarx, flesh; gala, milk), which is also supposed to be decomposed in the liver into carbonic acid and water (M. Foster, page 836), that all our dead tissue is, with a certain slight but most important exception, got rid of safely at last, as urea, carbonic acid, and water.[5] These are the final forms which the waste that passes from the tissue into the blood takes—the urea being separated from the blood and got rid of by the kidneys, the carbonic acid both by the skin and the lungs, and the water by all three channels of separation.[6]

But we said that urea, carbonic acid, and water did not account for quite all the waste tissue; and among the part not so accounted for are the very hurtful poisons which escape from lungs and skin. What are these poisons? Have they a connection with or a resemblance to the poisons which, as we know, exist at all times within the system on a large scale. Dead or waste tissue probably passes through many forms before it reaches the safe final forms of carbonic acid and water, and we must conclude that some of these forms are highly poisonous. We see this hy what happens to a man when he is drowned. A drowned man is in reality a poisoned man. The waste which is going on everywhere and at every moment in his tissues is producing a poison of so deadly a character that when it can not be oxidized by receiving oxygen from the blood (as it does under ordinary circumstances by means of the two gallons (nearly) of air he breathes in a minute) death ensues in a few minutes. In this case the poison produced all over the system has been no longer rendered harmless by oxygen, and goes as poison to the brain. Now, this poisoning does not appear to be primarily or necessarily due to an excess of carbonic acid, which also accumulates in the blood when a man is drowned. As Dr. Foster shows, even where carbonic acid is got rid of and no oxygen available the same result follows. Thus we have a pretty clear indication that the poisoning which results is the non-oxidization of certain active poisons. Other indications point to the same conclusion. When a man faints from loss of blood he probably faints because the diminished stream of blood does not carry a sufficient quantity of oxygen with it to neutralize the poisons which reach the brain.[7] It is also noticeable that in both these cases convulsions occur—that is, oxygen being denied, the poisons (which retain all their virulence, from being non-oxidized) act as a very powerful stimulant on a part of the nervous center, which, in turn acting through the nerves, throws one set of muscles after another (connected with the respiratory system) into action, in order to obtain the oxygen that is absent; ending at last in that general violent movement which is called convulsions. After a short time the poisons overpower the nerve-centers and death ensues.[8]

Both fevers and violent exercise seem also to illustrate the same thing. In fever the tissue rapidly wastes, and great quantities of waste poison are poured into the blood. These poisons affect the nerves, and are the cause of quickened respiration, and often of quickened circulation,[9] which are necessary in order to get the excess of poison oxidized; when, therefore, unconsciousness supervenes, we may say pretty confidently that the rapid circulation and the rapid breathing have not been sufficient to oxidize and neutralize the mass of poison which is being carried to the brain.[10] So, again, in pneumonia the quickened breathing shows both the effort of Nature to make up for the loss of that part of the lung which is ineffective, and also the stimulus which the increased waste poison in the blood (increased owing to diminished lung capacity, and therefore diminished oxygen) exerts upon the respiratory machinery. So, again, when less blood is carried to the lungs, owing to the artery which leads from the heart to the lungs being partially blocked with a clot, the same effect is produced. Probably a somewhat similar condition arises after hard work, either in old age or in a feeble state of health. The tissue, not being in the firm condition of the tissue of a vigorous person accustomed to daily work, breaks down in large quantities, while at the same time the circulatory and respiratory machineries are no longer at their best, and therefore the oxidation is imperfect. On the next day the infirm man is poisoned by the unusual quantity of waste in the system, and feels discomfort in many parts of his body or limbs. So, also, the discomfort acutely felt by some persons during east winds probably arises from the poison that ought to have been got rid of by the skin, but, owing to the closing of the pores, has been thrown back into the system. So also with ordinary violent exercise. When we take violent exercise an unusual quantity of waste is thrown into the blood, requiring an unusual quantity of oxidation. Here also the waste stimulates the nerve-centers, increasing action of heart, and of respiratory muscles, so that the blood charged with waste and the air may come into quicker contact. The successful

athlete is, therefore, first the good oxidizer (see M. Foster, page 628), the person who has good lung capacity, and especially a powerful heart to drive the blood swiftly; and, secondly, the person who trains well, whose tissue is healthy and firm and does not break down rapidly into waste—waste in his case not outstripping the powers of oxidation, and thus causing distress. On the other hand, the untrained man, who breaks down in the race with every symptom of distress, is the poisoned man—the man who formed waste quicker than he could oxidize it.[11]

Reviewing, then, what we have said, we seem to see three things: first, that so long as we have a sufficiency of oxygen, we get rid of a large amount of daily waste in safe and harmless forms; secondly, that when oxygen is withheld from us there are poisons in every part of our tissue of so deadly a character (either abnormally formed because oxygen is absent, or under ordinary circumstances neutralized by the supplies of oxygen present) as to take life in a few minutes; thirdly, that even when all is well, and our system is functioning under healthy conditions, we are still always breathing out from ourselves, through lung and through skin, certain dangerous poisons, which poisons, when we are living in bad air, we perpetually reabsorb into ourselves, to our own great hurt.

Nothing, however, that we have said satisfactorily explains the presence of these poisons which escape from the lungs and the skin. It seems hard to explain why, when Nature so successfully breaks down the great mass of waste into harmless products, there should be this comparatively slight residue left over—reminding one of a lawless fraction of people in an orderly state—which can not be got rid of on the same easy terms. As we have seen, we have about five pounds three ounces of daily waste that is safely got rid of as urea, carbonic acid, and water, by means of kidneys, skin, and lungs; but accompanying this safe discharge we have a few grains of poison—a sort of surplus of evil—which in some way or other seems to resist the oxidation to which all the other mass of waste has been subject. What, then, is this poison? How far is it the same, how far does it differ from the normal poisons of the tissues, which, as we see, in a few minutes destroy life when oxygen is withheld? Where and how is it formed? Are we to look upon it as a putrefactive poison formed at the surface of the lungs and the skin, when waste of some kind is escaping through these channels? Dr. Klein tells us (pages 61 and 241) that septic bacteria[12] (the authors of putrefactive change) are to be found in those parts of the body into which air penetrates, as the mouth, the air-passages, the whole alimentary tract; but it seems difficult not to believe, whatever changes take place as these poisons reach the air, that they must at all events have existed as chemical poisons when still in the tissues. Are we, then, to look upon these poisons as derived from putrefactive decompositions taking place in certain parts of the body; or as poisons derived from the tissues; or as in turn possessing both characters? At present, both within and without the body, their nature is surrounded with mystery, and many are the interesting questions that remain to be solved about them. When they have passed outside the body, are they the food of any of the bacteria which are found so plentifully in foul air?[13] If so, are the ordinary bacteria (excluding the case of certain bacteria producing disease) our friends or our enemies; do they render the poison itself harmless; or do they themselves produce an excretion which is of a poisonous character; or should they be looked on as neutral, destroying one poison and producing another; are the poisons themselves simply removed by currents of air, or are they oxidized in the air; if so, are they oxidized only when ozone is present (see Our Homes, page 11); and if in the air, why not in the blood, after we have rebreathed them and surrounded them with oxygen, in loose combination with hæmoglobin?[14]

Another light is thrown upon the waste poisons of the tissues by the statement that they exhaust the power of muscle to contract. Muscle taken from a freshly killed animal, if fed with arterial blood, or blood supplied with oxygen, may retain for some time its power of contraction. But if venous blood (blood that has lost its oxygen and is charged with waste poisons) be injected into it, the power of contraction is lost quicker than if no blood be supplied to it. In the same way the power of the muscle is soon exhausted if a solution containing substances which can be extracted from muscle (such as kreatin, lactic acid, etc.) be injected into it (M. Foster, page 150). These facts help us to see the local mischief which must often arise from these poisons, as well as their effects on the nerve-centers. Many an ache and pain are probably due to local effects of the waste poisons, whether they are the normal waste poisons of the system, which under unhealthy conditions of life we are not properly getting rid of, or the special waste poisons of skin and lungs that we have rebreathed into the system.[15]

We now pass to other evidence affecting the poison that escapes from lungs and skin. We all know that a room is offensive when many people are crowded into it; we know the unpleasantness of a bedroom before the air has freely entered it; we know how disagreeable the breath and the clothes can be; we know that animals die when submitted to air that has been breathed, even when the carbonic acid has been removed;[16] we know how necessary is the continuous flood of pure air in hospitals—we have heard it stated that this much freer admission of air is rendering unnecessary the antiseptic treatment of wounds; how by treating men in the open air and in tents recoveries have been made quicker and better than in hospital;[17] and how in the case of the Austrian army "the most severe maladies ran their course much more mildly" in the free air, while the recovery was quicker and more perfect (Ransome, Health Lectures, 1875-'78, page 151). So also Dr. Parkes says (page 181) in cases of blood-poisoning, the best treatment is complete exposure to open air; so also in typhus; and in a less degree in enteric fever, small-pox, and plague. "This complete exposure," he adds, "of patients to air is the most important mode of treatment, before even diet and medicines."[18] In

the same way, the deaths of the Black Hole of Calcutta add their evidence, though it is an evidence of an extreme kind. While out of the one hundred and forty-six persons shut up, one hundred and twenty-three died, of the remaining number (Carpenter, page 357) many afterward died of putrid fever—that is, were poisoned, owing to an insufficiency of oxygen to neutralize the poisons breathed out on all sides of them, and rebreathed by themselves. A much simpler piece of evidence is presented to us daily by our own eyes. Who is not struck by the pasty, anæmic look of our city children, and of the large number of those who follow sedentary occupations, as contrasted with the looks of those who live in the country and are much in the open air? What is that pasty, anæmic look? It is the absence of red corpuscles from the blood, indicating that where oxygen is deficient[19] the red corpuscles are not produced in their proper quantity. So also the effects of living in rooms in which sewer-gas has penetrated illustrate in their own stronger degree the effects of living in unventilated rooms. The one is the lesser form, the other the more serious form of the same evil. In both, bacteria thrive and multiply, and in both, meat and milk rapidly taint. They are both full of organic matter, and the symptoms of headache and feverishness are common to both, though, of course, the case of sewer-gas is much the more acute case.[20] Again, we all know the wonderfully restoring effect that hill air with its ozone has upon us after town life; showing how the poison has depressed all our functions, and how the pure air restores their energy. We see the same effect in the lives of work-people. Sir D. Galton, as we have seen, tells us of better work done, more energy, more appetite, when air is introduced into unhealthy work-rooms. Dr. Parkes tells the same story. Dr. A. Ransome, speaking in 1875, quotes the case of the Guards, picked men, highly cared for, yet who died quite as fast as the civil population. Why? he asks. Mainly from defective ventilation of the barracks (Health Lectures, 1875-'78, page 150).[21] Again, we find disease attacking country districts for the first time, where houses had been improved, and the ventilation, which used to take place through porous walls and less well-fitting windows, has been done away with.[22] So also it is stated by Mr. Angell (Health Lectures, 1879-'80, page 31) that in the old crowded lodging-houses people sleeping on the floor would escape fever, while those sleeping on the bedsteads would be struck by it. Those on the floor got ventilation from the door and fireplace; those on the bedsteads were above the line of it—the colder

and purer air being heavier than the heated impure air, and therefore nearer the line of the floor.

Animals furnish the same evidence. Cows and horses both suffer grievously from want of ventilation in their stables; and cattle, though they require warmth for fattening, still put on flesh better in a colder but well-ventilated place than in a warmer place which is unventilated (Parkes, page 180). So also Parkes tells us about the French cavalry. Before 1836 the mortality among the horses varied from 180 to 197 per 1,000 per annum. With the enlargement of the stables and increased quantity of air, the loss was reduced to 68 per 1,000, and finally to 281/2 per 1,000, and of officers' horses to 20.

Then we have the evidence of the ordinary tests for ascertaining the purity of the air. Air fouled by respiration discolors permanganate of potash and robs it of a portion of its oxygen; the amount of organic matter is then measured by the number of volumes of oxygen required to reoxidize the permanganate and restore it to its former condition. Another test is the presence of certain bacteria, which are found in large numbers in foul air, increasing out of proportion to the molds or fungi found in the air, which appear to be much less affected by impurities. It is stated that these forms of life all originally come from the open air—that reservoir of all things—though they are supposed to multiply in congenial quarters when once they have found an entrance. The significant fact, however, is their number, which might seem to show that they prosper just because they have discovered their proper food—the organic poison which Is poured out into the air from our lungs and skin. On this point. Dr. A. Ransome makes an interesting speculation, which we quote from memory—a wrong thing to do. Impressed with the belief that consumption is communicable in foul air, and non-communicable in good air, he believes that the bacillus (a form of bacteria) which conveys the disease retains its virulence more in foul air than in pure air, and is thus better able to make a lodgment in the human system.[23]Contemporary Review.

[To he concluded.]

  1. It must be remembered that the act of breathing consists in bringing the blood of the system in contact with air, through a delicate membrane in the lungs. Here an exchange takes place—oxygen being yielded up from the air to the blood, and carbonic acid from the blood to the air.
  2. We do not know on what exact grounds this calculation rests.
  3. Foster (p. 552) states that "when the expired air is condensed. . . the aqueous product is found to contain organic matter, which, from the presence of micro-organisms, . . . is very apt rapidly to putrefy." L. P. writes: "If a globe be filled with ice and taken into a close, badly ventilated room, the dew which forms outside is found to be contaminated with these organic impurities." L. T. writes: It is more than likely that it is this animal poison which is the direct cause of typhus fever as that follows overcrowding with mathematical precision."
  4. A considerable quantity of air, however, is always entering through window frames, under doors, even through brick walls. On the other hand, we have made no allowance either for space occupied by furniture or for the (probably) tainted condition of the room.
  5. We are not taking into account certain other substances discharged from the skin in small quantities.
  6. "The natural waste of the body appears in two simple forms of carbonic acid—the gaseous form having the chemical formula CO2O2, while that which is got rid of in solution is urea, that is, CO,(NH2)2, in which the second atom of oxygen in the carbonic acid is replaced by a nitrogenous body termed amidogen."—(L. P.)
  7. One of the writers was informed by a friend in Africa that he was present when a man cut himself badly with a bill-hook and was carried into a cabin. Each time the door was closed the roan fainted; each time the door was thrown open he came back to his senses, indicating pretty clearly that the supply of oxygen, which was unduly diminished by the loss of blood, was increased when the door was open, and was just sufficient to neutralize the effect of the waste poisons and prevent unconsciousness.
  8. It Is interesting to remark here that this reaction of the nerve-center under the effect of the poison seems to be of that "protective character" which occurs so often, and to which Prof. Foster more than once has referred—that is to say, that it produces a violent movement of the muscles in the effort to obtain air, which can alone neutralize the mischief.
  9. In certain cases, however, the heart and circulation are slowed, not quickened. This is the case, Dr. Foster says, in drowning after a slight quickening has taken place. May this not be explained by the supposition that, where oxygen is altogether denied, an increase in the rapidity of the circulation would carry the poison quicker to the brain, and therefore hasten the end? A different effect seems to occur in the case of vitiated air. In this case Müller asserts (as quoted by Mr. Angell, Manchester Health Lectures, p. 33, 1879-'80) that the circulation is slowed. Is this—if correctly stated—a consequence of the depressing action of these peculiar poisons, which escape with the breath, and are rebreathed in vitiated air? The case of flies which died in foul air with unexhausted tissue, alluded to later on, and some other evidence, seem to point in this direction. In exercise, on the other hand, the effect is, as one would expect, different: both respiration and circulation are quickened in order to increase the supply of oxygen required to meet the large increase of waste; thus it would appear as if the ordinary waste poisons stimulated, while the special poisons of vitiated air depressed. The whole subject calls for very careful consideration. A friend remarks that Dr. Burdon Sanderson, of Oxford, has long been and Is working out these questions.
  10. This indicates very clearly that the purest and freshest air should flow through the room of a person suffering from fever. It would be almost as necessary to him as to the person suffering from loss of blood. Such treatment is confirmed by experience (see case of Austrian army, further on).
  11. In such a case it may be asked, Why are not the waste poisons passing into the blood from the tissues safely got rid of in the form of carbonic acid and water when the blood reaches the lungs? It seems difficult to escape from the conclusion (see Foster, p. 603) that these unoxidized waste products may, on occasion, pass the lungs without being got rid of. In the case of violent exercise, it would seem that the quickened heart and quickened breathing must come from the action of waste poisons, which, passing the lungs, reach the medulla and stimulate the nerve-centers, there not having been time, owing to the excessive quantity of waste produced, to reduce all the waste to the safe final products of water and carbonic acid, and therefore some part of the waste in an unoxidized state being carried past the lungs on to the nerve-centers. As regards the poisons we rebreathe from the air, it is, of course, rather a surprising thing, if they entered the circulation, that they should not be oxidized in the blood when we think of how they must be surrounded by the oxygen that the blood has received from the air. But active as oxygen is—in its "nascent" state, just released from hæmoglobin—in the tissues after leaving the blood, there are reasons for thinking that this activity does not exist in the blood itself. Thus we are told that pyrogallic acid, which is an easily oxidizable substance, may pass through the blood without undergoing any change; and fresh blood, as we are told, has little oxidizing effect. This strange powerlessness of the oxygen in the blood increases the danger of these waste poisons. If they were oxidized in the blood we should be able probably to got rid of them quite harmlessly, as they would not be in the condition of poisons when they escaped from lungs and skin; but we may feel sure that there is some good reason why this can not take place. When they are once carried to the tissues, except in the case of persons taking plenty of exercise and leading a healthy life, there may be no superabundance of oxygen, but rather a deficiency, for all the work to be done.
  12. For a different view, see De Bary on Bacteria, p. 44.
  13. Bacteria (Gr. bakterion, a staff) are the smallest living organisms known, and generally included in the vegetable kingdom. They possess a very simple structure, are capable of free movement, and multiply very rapidly. Some kinds are the causes of putrefaction and of certain diseases. It is calculated that we inhale 300,000 germs of these organisms in the day.
  14. Mr. Wager adds the following note: "The bacteria on the surface are constantly at work excreting. At every breath we give off a small quantity of poison, whether we are breathing in pure or bad air. The quantity given off is extremely (extraordinarily) small—so small that it can only be approximately measured by the amount of carbonic acid in the air. These bacteria are present whether we live in foul air or pure air. Their existence there means that they can thrive, and if they thrive they must feed, and if they feed, they must excrete, or something analogous to it. Personally, I am inclined to think they (these special lung and skin poisons) come from the blood, because ptomaines can be formed by the action of various chemical agents (such as acids) upon protoplasmic or albuminous material and as blood (serum) is albuminous, and as it contains various substances derived from tissue waste—e. g., lactic acid, uric acid probably, etc.—it may be that the two react upon one another, producing these ptomaine-like poisons. I think, however, that it is just possible that they may be formed on the surface.
  15. Where Nature does not get fair play, where, for example, the blood is vitiated by our constantly rebreathing poisons that have been already got rid of, other dangers probably exist. In the delicate chemical translations which take place when tissue is being changed into harmless waste, it may happen that the process goes wrong, and an abnormal poison is formed. Thus, under certain circumstances, instead of urea, uric acid is formed; thus in uræmia, or retention of urea in the system, various secondary compounds are formed (Carpenter, p. 448), which act on brain or spinal cord as narcotic poisons; thus, in acute yellow atrophy, where liver-cells lose a part of their activity, a substance called leucin is manufactured to a considerable extent instead of urea (M. Foster, p. 755); thus gall-stones are formed instead of gall, and certain changes take place in the bile, by which some of its constituents cease to be dissolved in it (M. Foster, p. 431); thus the ptomaines—a class of mysterious poisons—are formed in the system (Quain, Ptomaine, p. 1816) after various illnesses. [In connection with these ptomaines a dispute arose during an Italian trial as to whether a poison detected in a body was strychnine, or this naturally formed ptomaine.] Thus, too, Blythe (Poisons, A. W. Blythe, pp. 468-470) describes cases in which narcotic poisons have been formed by synthesis of substances in the tissue or in the blood. So also we might quote the interesting speculation of Dr. Carpenter (p. 368), that a cancer is an excretory organ, formed to get rid of poisons in the system, illustrating once more "the protective nature" even of that which brings pain and death; and the case of certain pathogenic organisms, which, as Dr. Klein suggests (p. 248), may not affect healthy living tissues, but only diseased tissues—the disease implying alteration of the tissue. All these cases are cases, doubtless, of an extreme kind; they imply the abnormal formation of poisons to a serious extent, sufficient to constitute illness; but it may well be that there are many less serious formations of abnormal poisons, which, though not sufficient to produce illness, yet cause much discomfort, and which-are the consequence of the vitiated state of the blood, arising from the habitual breathing of impure air.
  16. If we remember rightly, both Parkes and D. Galton (Our Homes) refer to these experiments—a mouse dying in forty-five minutes when submitted to air treated in this manner. Dr. Richardson also refers in one of his works to experiments, which were conducted by himself, and which are more fully described in a report to the British Association. Dr. Richardson had formerly a theory of "devitalized oxygen," but we suppose he would probably consider now that it was a truer statement to say that this special poison had not been removed from the air which the creatures breathed. Experiments of the same kind have also been made on rabbits in Paris. One of our number (A. H.) adds the following remark: "Though I think probably it would be quite misleading to speak of the experiments upon the mouse, and the experiments conducted by Dr. Richardson as in any sense cruel, yet, speaking my own personal opinion, I remain opposed to all such experiments. While I admit the neat and convenient evidence often supplied by them, and also admit that difficulties of method would at first exist, were they renounced, yet I think the wealth of materials that exist on all sides of us for pushing forward knowledge is so vast, that however convenient these experiments may be, they are not really necessary, while perhaps a keener perceptive sense in tracing out the meaning of the things of common life, which are of such vital importance, would be developed, as investigators renounced this particular method. In writing this, however, I am governed by the moral side of the question, which is the one that, apart from all other considerations, determines my view."
  17. The case of the hospital is, of course, a complicated case, and it might be disputed how far its evidence can be used for our purpose.
  18. "When our health commissioners were sent out to the Crimea to examine the heavy mortality among soldiers in the hospitals, their first act was to use their sticks to break some hundreds of glass panes in the windows, so as to admit air freely. After that the wounded recovered rapidly."—(L. P.) In the same way Dr. Clifford Allbutt reduced the mortality in a heavy epidemic of typhus fever in Leeds by fastening the windows in the fever hospital with screws, so that they could not be shut. He remarks that in Ireland those attacked with typhus, who were put out to die, would often recover.
  19. But why is oxygen deficient in these cases? Is it, once more, because so much organic poison is breathed in with the air of the shut-up rooms, that the functions are depressed and imperfectly performed; that, for example, the act of respiration is impaired? Or does the poison directly affect the formation of the red corpuscles?
  20. It has, however, been shown recently that the air in a well-ventilated sewer is, so far as organic matter and micro-organisms are concerned, purer than the air in a small, badly ventilated room.
  21. "Sir Lyon Playfair, one of the commissioners for inquiring into the state of barracks, passed a couple of nights with the soldiers in their crowded sleeping-rooms, and found the air saturated with organic effluvia which discolored permanganate of potash. The mortality iimong soldiers is now greatly reduced by the better ventilation enforced by the commission."—(L. P.)
  22. A case of this kind is reported to us by Mr. Alexander Campbell, of Auchindarroch, Lochgilphead; and we believe that the same thing was observed in a Westmoreland district. In an interesting letter Mr. Campbell writes: "Some years back I was asked by a medical officer of large experience in the Highlands regarding a phenomenon which had puzzled him. He had exerted himself much, and with great success, to have improved cottages built, but in proportion as the cottages grew better did the health of the people grow worse. I gave him my opinion that in tho old, uncomfortable-looking cottages, built may be of dry stone, and open to the roof, the people were kept healthy in spite of themselves by the wind blowing through them, while the new cottages, tightly built, and with well-fitting doors and windows, excluded the air, and the windows being seldom or never opened, the inhabitants were poisoned. He said he fully agreed in this, and would ask for no more new cottages until the people had learned how to live in them. I have found a considerable amount of ill health among the paupers in the island of Tiree, which, from its situation, exposed as it is to the free action of breezes from the Atlantic, should be one of the healthiest islands of the Hebrides. I attribute this to the mode in which the houses are built, with two walls two or three feet apart, the interval being closely packed with sand. The air is thus hermetically excluded, and unless the windows are made to open, and are freely opened, the inhabitants are constantly, when within their dwellings, breathing vitiated air." It is also worth while quoting from a review of Major Fisher's book (which book we have not read) in The Spectator, May 2, 1891, Through the Stable and Saddle Room: "Everybody knows something of the importance of ventilation, both for man and horse; but it is not so widely known as it ought to be that, while horses seldom or never take cold through being exposed to cold, they are often made ill by being too warm. [It is not the warmth; it is the impure air.] It is the inside, not the outside, air that gives them coughs, sore throats, congestion of the lungs, and sundry other ills to which horse-flesh is heir. For this reason, old ramshackle stables, full of cracks and crevices, are healthier than brand-new buildings with tight doors and windows and impervious roofs. Our author, who never generalizes rashly, and supports his theories with copious instances, mentions one or two curious 'cases in point.' Remounts for cavalry regiments, which are mostly of Irish extraction, have often to travel in severe weather part of the way in cattletrucks, with no other protection from the cold than their own coats. Nevertheless, the remounts nearly always arrive at their destination in perfect health; yet they are no sooner placed in stables, however well ventilated, than they begin to suffer from coughs and colds, which generally end in strangles. During the autumn manœuvres of 1875, Major Fisher's regiment was encamped near Aldershot, and though it rained almost incessantly, and the horses were picketed in the open, without so much as a blanket to cover them, colds and coughs were unheard of, and the favorite charger of one of his brother officers, which at the time she left the barrack-stable suffered from a severe cold, was made whole by a few days' exposure to the elemental strife." The book should contain some valuable facts.
  23. This speculation of Dr. A. Ransome's suggests another speculation. Dr. Klein (pp. 238-248) believes that in the interior of healthy human tissue no bacteria, which cause putrefaction, are found. They are found abundantly in those parts of the system to which air penetrates, as, for instance, in the mouth, or in the alimentary canal; and from the alimentary canal they pass easily, as the food itself does, into the diminutive blood-vessels or the diminutive lymphatics (locally called lacteals) that line the walls of this canal. Cut if the blood is in healthy order they seem to perish, dying for want of food. Dr. Klein goes on to state that if at some point they are carried to tissue that is in an unheal. by condition, there they may obtain a footing and begin to multiply. He does not actually state, as we understand, that the unhealthy condition of the blood keeps them alive, but he implies it; and it would seem probable that the unhealthy state of the blood—for