the market which use the wick system are (a) too little surface, (b) hand feeding, (c) clogging of wicks by deposits from water.

I have been able to greatly increase the surface by arranging close parallel troughs either across or lengthwise to the radiator. A sufficient evaporation is possible by this arrangement.

Automatic feeding I secured by the method shown in Fig. II. I had one such humidifier running for six weeks without touching it and estimate that it evaporated nearly a barrel of water a week.

So far as the third difficulty-namely, clogging of wicks-is concerned, I find it is less if the wicks are never permitted to get dry, as they are almost sure to do in any hand-fed system. I also find that cheap wick substance such as blotting paper and the heavy absorbent paper used by botanists as plant driers are just as good as the fancy wicks found in the apparatus sold in stores. These paper wicks can be used for a while and thrown away.

Unless a slightly, efficient, automatic humidifier for hot water systems can be worked out along the lines indicated, I believe that those who have hot water heating will have to fall back on accessory apparatus such as electric fans to aid evaporation, or special water boilers to put vapor into the air. Such apparatus has been patented but apparently has not proven a commercial success. It would surely be somewhat expensive. Remember you have to face all the time the necessity of evaporating one third to one half a barrel of water a day for an ordinary house.

So far as steam systems are concerned the problem seems easier. There are devices on the market for letting steam out noiselessly into the room. I have not tested any of these; but if large enough they ought to be efficient as moisteners. But engineers state that they are dangerous in that they lower the water level in the boiler and that no safe automatic boiler feed is known.

Another method used in steam systems is to provide steam coils to boil water in separate receptacles. This is free from the previous criticism and ought to be effective, provided said receptacles furnish sufficient free surface of water-air contact and also provided auto

matic water supply to the humidifiers is arranged.

The older hot air furnaces often had a small water tank at the base of the air space. This was totally ineffective. I tested one that evaporated less than a quart a day.

Later types of furnaces have a tank above the fire box. These must be better, but the examples I have seen offer only a small water-air contact, and I should want an actual test before endorsing them.

Nevertheless if I were to put a heating system into a small house in Minnesota in the present state of development of hygiene and of heating engineering, I would choose a hot air furnace. I would have no outside air flue, but rather a cold return flue from every room to the base of the furnace. I would look to this system to secure circulation, which we now recognize as a very important hygienic factor. I would trust to leakage for renewal. I would have double windows, expecting even with these to have ample oxygen for an ordinary family. I would supply moisture by a sufficient number of broad shallow pans just above the fire pot, the water level in these being automatically maintained by connection with the city water system. I would have a good phychrometer and see to it that the relative humidity was kept above 40%. I would have a good thermometer and keep the temperature at 65° F. unless the women folks complained, and not above 68° F. even if they did complain. I should expect good health and comfort dividends on the outlay of money and trouble required to get these conditions.

It will be seen that I have confined my discussion to houses and other places where few people assemble. The humidity problem is entirely different for public halls. Remember that each person gives off in the neighborhood of one quart of water as vapor each twentyfour hours. One hundred people give off twenty-five gallons. Three thousand people give off twenty-five barrels. Excess humidity is ordinarily the cause of discomfort in theatres, picture shows, etc. Public halls in this climate ordinarily need artificial renewal of air and a lower temperature rather than artificial humidification.

DISCUSSION.

DR. H. W. HILL: I wish to express my gratification at hearing the Dean of the University of Minnesota Medical School preach to this high-class medical audience the very facts that brought me nearly to crucifixion for stating them three or four years ago. Particularly that the circulation of air was quite sufficient for ventilation and there is no necessity for opening windows.

As to the ladies objecting to low temperatures, a county superintendent related to me a method which he had employed of overcoming that difficulty. He found that the teachers were complaining very much of a temperature of 65 degrees. The thermometers were at this height on the wall. (Indicating a height of about 42 feet above the floor.) He put those thermometers up a foot or so higher, where they registered 68, and there was no further trouble. (Laughter and applause.)

DR. L. M. ROBERTS, Little Falls: I would like to commend this paper as dealing with my own experience regarding a hot-air furnace. Some twelve years ago I put in a hot-air furnace. I had a very large old-fashioned house with double windows, and when the plumber put in the water tank he put it in at the base of the furnace. I asked him why he put it in there. He said, "They all do it." I said, "What for?" And he said, "To evaporate the water." I said, "What do you put it in that part of the furnace for?" He said, "Oh, they all do it that way." I said, "Go ahead, you are the furnace man." So he went ahead.

At that time I had a man who had been a locomotive fireman in his day taking care of my furnace, and we found that with the temperature as high as 80 degrees we were not comfortably warm and we were very uncomfortable at 70, and the air was dry and smelly and altogether unsatisfactory. My wife had some heavy portieres between the living room and the parlor, and they shrunk up about 4 inches from the floor, and our furniture went to pieces, and my wife was almost distracted and wanted another type of furnace put in. I said, "No, that furnace is calling for water and it is going to get it;" and I studied it out and I got a tinner to come up to the house, and I had him cut a hole in the jacket at the top of the furnace and make a galvanized iron receptacle 5 feet long and 8 inches wide and about 8 inches deep, which held 7 gallons and a half by actual measurement, of water. It rested on the peak, the top of the furnace, and all inside jacket. The trouble stopped; the portieres came down, the furniture went back to normal and my wife was satisfied. Best of all, the temperature of 65 is all we have cared to maintain since. There has never been any humidity on the glass anywhere, the wallpaper has never been affected, and the atmosphere is exceedingly pleasant and very sweet. It is automatic. In extreme weather I calculate that I burn as high as 35 or 40 gallons of water a day in that receptacle. The hotter the fire the greater the

evaporation. You can sometimes hear the water boiling. It is right where the hot air rushes past it and is carried up into the house. It is a very distinct success.

I want to say another word about ventilation. All of you who have been accustomed to being out late at night, and leaving your home and going into some other people's homes, and then returning to your own, have doubtless often noticed the difference in the atmosphere. I do not care how hygienic people try to be or how carefully they ventilate during the day, when they are shut up at night and you go into an ordinary house at 2 o'clock in the morning, and you have a hot water or steam-heating plant, the house smells. It may smell of perfume, it may smell of more or less sweet odors, but the house smells. This is what I call the acid test of any ventilating system, and in winter heat and ventilation should be synonymous terms. You may go into a house that is heated as my house is heated after we have had a stag party there, and everybody has smoked until the air is absolutely blue, two hours afterwards that air is absolutely odorless. I certainly commend my method and advise my friends to adopt it, as a great saver of fuel and health. Previous, we noticed the irritation in our throats and larynxes very markedly with that dry air, but with this moistened air it is very much like a June day.

And it is certainly a great saver of coal. When we first started in with the other method we burned as high as 12 tons of coal, ineffectually trying to warm the house. Since this, I do not think any winter, and that has been over a period of 10 or 11 years since, I do not think we have averaged over 9 or 10 tons with the same house.

DR. J. C. BOEHM, St. Cloud: A winter or two ago I was calling on the Dean for a meeting. I did not get the proper notice, so I had to stay over at his house, and I saw him experimenting with the humidifier. We exchanged a few remarks. For that reason I came up here to listen to this paper.

At this time, when the price of coal is so high and the quantity of fuel is so scarce, we ought to put our heads together right now and hire men, if we cannot get them otherwise, to perfect something which would reduce the required temperature in our houses, in our schools, churches and other places which have to be heated.

Some years ago I came into my house which was at a temperature of 68 or 70. I took off my coat, and I was chilly. I was alone in the house. I covered all the rugs on the first floor with about 3 inches of snow and waited an hour and a half. The snow disappeared, of course. I looked on the floor; there was not a drop of water there. I sat down and was comfortable. I had lowered the temperature in that house from 2 to 3 degrees. I was then convinced that although I have a hot-water system, that I would not have a hot-air system, for the simple reason that I have yet to find one (except Dr. Roberts'), that brings in a sufficient amount of moisture into the system to overcome the monoxide that is

being formed by the heated air that comes in contact with the hot iron. If that can be overcome the hot-air furnace may be all right.

Dr. Lyon has given us the mathematical explanation of our body evaporation, the amount needed, and has advised a very good humidifier. He did not show me that until today.

I myself have tried various schemes, and the best one, if you wish to supply the water, is to have a pipe leading along that radiator. Stretch a towel right across here (illustrating). A linen towel is better than any other kind. Your pipe should be slanting with holes in it, so that the water drops down, and a receptacle such as a five gallon pail beneath. It is not very pretty but it does the work. You will be surprised how easy it is to live in that room at a temperature of from 62 to 65 degrees.

I wish we had a mathematician here to figure out the amount of fuel we would save if we all did that, and especially at this crisis. I do not think that too much publicity can be given this topic, and this paper, and to bring it into every household.

Tell the salesman that this is no good (referring to a device which had been exhibited by Prof. Lyon during his address.) I have half a dozen of them. Mine have even a wick, and by capillarity it is supposed to evaporate some water. This has not got even that.

The other experiment I performed was in St. Paul, with my father-in-law, who is a contractor in the plumbing and heating business, and I have talked with him about this. He said, "We will fix up a little arrangement;" and he went to work and connected with the waterworks in the house, and 1 brought down a sprayer, and we took a half-inch pipe, and on top we had the nozzle strike a kind of umbrella-shaped affair, and that gave a nice spray, and behind that we had a little electric fan which did not use very much electricity. In thirty minutes the house was comfortable all over, by the use of the fan running thirty minutes. And whenever after that the house was cold, we did not go down and shake the furnace and build a bigger fire, but simply started the fan, and the vaporizer, as we called it, and the house got nice and comfortable.

That which I wish to direct to your attention is, what is it that makes us feel cold? Take a room at 65 degrees, and in the winter the ladies will claim that that is too cold. Why is it too cold? Because the evaporation away from the skin into the dry atmosphere makes it feel cold. If you take a bottle of alcohol and have it sitting in a room, it does not take long before the temperature of the alcohol in that bottle is the same as that surrounding it, 65 degrees. Take ether, which is a little bit better, and the same thing is true. Put the alcohol or ether on your hand, and see how cool you get it. Why? It is because the evaporation has gone away from your skin. All these things tend to seek their level approximately or absolutely. And if the atmosphere is saturated approximately to that same degree that our body is, there will be no evaporation away from

the skin, and we feel comfortable at 62 degrees. If on the other hand, the atmosphere is dry, there will be evaporation and you will feel cold at 70 or even 75.

The question the Dean asked was as to the therapeutic effect or the pathological effect, which was it, that this dry atmosphere has? My personal knowledge and experience have been in my practice. I have now before my mind five families, with from four to seven children in each family, that had sore throats from the time they started the furnace and the weather began to be near zero, until it got warm enough so they could open the windows and have the air come in. I kept drumming at them to throw out the hot-air furnace, which they finally did. They put in a humidifier. That evidently had a good effect, because they did not get sick any more and I lost their practice. A lady who previously complained of being cold at a temperature of 70 or 72 degrees, now sits there thoroughly satisfied in a temperature of 64 or 65.

DR. L. M. ROBERTS, Little Falls: I had my waterworks arranged so that there is a pipe right off of my tank with a short section of hose, and it is no labor at all to keep the tank full. Any time any one goes down to the furnace he looks at the tank and can easily keep it filled. All that is necessary is to push a small trapdoor open, put the hose in and turn a stopcock. There is no carrying of water. It is a great convenience to have the water system arranged in that way.

PROF. E. P. LYON (closing the discussion): The psychological factor is well illustrated by Dr. Hill. We have to be careful in drawing conclusions because people "feel" a good deal according to what they think. If they think the temperature is 70° when it is really 65°, they feel better than if they think it 65° when it is really 70°!

I have a little evidence, which though not strictly scientific tends to confirm the general impression of feeling more comfortable with higher humidity. In my own house last winter I set the regulator so that the temperature was at 68°, without the women folks knowing anything about it; and with the higher humidity which I now maintain, there was no complaint, although in previous years at 70° to 72° there had been complaints. The ladies dress more lightly than the gentlemen, which is one reason why they complain more than we do.

This psychological factor made me say nothing at all about possible coal saving. We often hear it said that there is a saving of fuel if proper humidity is maintained. But I know of no experimental data. If any of you have absolute records on your coal extending over a considerable period of time and under varying humidities I should like them very much. I should like the facts in tons and dollars rather than general statements founded on general impressions. I believe there is a saving but I don't know. You have to evaporate more water to get humidity, and that takes more heat; but nevertheless, the loss of heat from the house in radiation

from the walls and leakage through them must be less when the temperature is lower than when the temperature is higher. Of these factors I should suppose the latter would more than compensate the former. I should be particularly gratified to have any of you send me distinct observations which satisfy you in this matter, or distinct records of coal used which any of you may have. DR. J. C. BOEHM, St. Cloud: May I add one word more? Dr. Lyon spoke of spoiling the wallpaper. That can be overcome very easily. But of course you have to build your house for it. You cannot go into an old house and do it unless you tear off the siding and rough boards outside. But when the house is built, if it is a frame house, between the studding you should put plenty of paper over this way (illustrating) and nail the lath over it, creating dead-air space. Have good building paper, of good quality. In front of this, lath another one, and so on, until you have practically several air-tight spaces, but not air-tight like Dr. Hill wants it, but that will allow the air to become warm inside and gradually cool on the outside, and it will prevent that precipitation that Dr. Lyon spoke of.

PATHOLOGY AND TREATMENT OF OSTEOMYELITIS.

ALEX R. COLVIN, M. D., St. Paul, Minn.

The one feature of osteomyelitis that cannot be too often dwelt upon is that it is most frequently an acute destructive inflammation of bone, and that the bone should be opened early and widely. One will not be lessening the emphasis on this feature by saying that it is at the present day difficult to imagine anyone failing to open a bone under such conditions after the diagnosis has been made, but one can readily understand a difficulty in diagnosis in the early stage of the trouble, and for some reason or other we hesitate to do exploratory operations on bone as readily as we explore the abdominal cavity. Under urgent circumstances, however, it is just as imperative to do SO. Once the pathology of the disease is mas

OSTITIS ACUTE

OSTITIS CHRONIC

tered, the more extensive and difficult anatomical knowledge required need not deter us from exploration.

The classification given in the table shows the area of bone which may be involved, and enables us to carry clinical pictures, but we must realize that after all the disease is one affecting the whole structure of bone and that any localization of it is in a sense accidental.

The question of periostitis needs some consideration. Unless we think of periostitis as really part of an ostitis we are liable to err in treatment.

In acute hematogenous infections the incidence of periostitis means that the infection has travelled from the interior of the bone and that pus has accumulated beneath the periosteum. We have been deceived in the past because on opening such subperiosteal collections the condition was recovered from at once and hence we concluded that the interior of bone was not involved. We know now, however, that even with extensive involvement of the interior of the bone, nature may establish drainage and the condition be recovered from without surgical assistance of any kind. While this occurs often enough, neverthelesss it is exceptional and must not influence us in our conduct of the treatment of acute infections except by proving that periostitis is not an independent condition and that opening the bone is essential.

The mere opening of the bone is neither difficult nor hazardous. The difficult part of the dissection is to reach the bone.

Joint complications, necrosis with its prolonged and complex pathology, will be less often encountered if the opening in the bone has been extensive enough to establish competent drainage.

Having recognized the osteal character of the infection, the localization of infections is the next most important item in pathology. This has become such common knowledge that one scarcely need refer to it except to empha

Acute Periostitis

Acute Central Osteomyelitis Acute Osteomyelo-perioslitis Acute Perisstitis

Acute Central Osteomyelitis Acute Osteomyelo-periostitis

size by illustration the resulting lesions. It will be noticed in the illustrations how often the trouble is located in the shaft rather than in the epiphysis, indeed epiphysitis in pyogenic disease is quite rare. The anatomy of each individual bone must, of course, be kept clearly in mind to enable us to realize the possibility of shaft, epiphyseal and joint involvement. The frequency of purulent arthritis of the hip in infections of the upper end of the femur, for instance, is due to the fact that the diaphysis or shaft is included within the capsule of the joint. In most of the other joints only the epiphysis is thus included and consequently because of the infrequency of epiphyseal involvement purulent arthritis is uncommon, the attending joint swelling being as a rule serous in character. The infecting agent having arrived at a certain point in the vascular areas of the bone, the resulting conditions will depend upon the virulence of the invading micro-organism and the resistence of the organism involved.

The great variability in the clinical and pathological manifestations of infection can be beautifully shown in bone. An acute general septic invasion where the bone infected is but an incident in the process of annihilation of the individual, contrasts markedly with an infection of one or more bones so slow in its progress and indolent in its manifestations that sarcoma is mimicked. Drainage having been established, restoration to the normal may occur especially in the young. On the other hand, in spite of drainage, destruction may proceed slowly, necrosis may have been limited rather than presented, and the complex condition of sequestrum formation and bone regeneration in vary ing ratios, is encountered. It is in this stage that radiographs furnish us with valuable information. Taken from time to time they show quite clearly the separation of the sequestrum and the formation of the involucrum. much as bone regeneration and production play so important a part in the complex pictures of destruction and repair, a clear conception of the share taken by the different parts of the bone in repair is essential.

Inas

Much speculation has been indulged in regarding this osteogenetic function of the various divisions of the bone tissue. It is now conceded that the osteoblast whose mesoblastic

origin and relation to connective tissue has always been acknowledged, is the dominating factor in bone regeneration; whether this tenacious cell is locked up in bone lacunae, lines the boundaries of the medullary cavity, clings to the trabeculae of the spongy tissues, or congregates on the confines of the compact tissue beneath a limiting or protective membrane, all are agreed that it is an integral part of bone, having the same vital connections with its surroundings that other cells have, and that regeneration of this most highly differentiated connective and supporting tissue is presided over by the familiar osteoblast.

Bone production goes hand in hand with bone destruction in the chronic stages of the disease and this may result in localized thickenings on the surface, or in a surrounding new shaft, or to a uniform thickening of the old shaft. This latter condition may result from a slowly progressive infection without any actual bone destruction.

The recognition of these facts is of the utmost importance in enabling us to interpret the complex pathological condition as seen in the radiograph. Our operative treatment is really an unravelling of pathology and can be much more intelligently done under radiographic guidance. It is sometimes said that if acute osteomyelitis were treated properly there would be no such thing as the chronic stage. This is only true in part, for many cases are so insidious in onset that marked bone changes have occurred before we see them at all, and before the patient has had any symptoms impelling them to seek assistance. It is in these chronic forms that the greatest difficulty in dignosis occurs because of the tumor-like thickening of the bone with few symptoms; and tumor-like masses of indurated tissues surrounding the bone increase the difficulty.

After the removal of the sequestra, each case. demands separate consideration as to the best means of dealing with the resulting cavity. In the young where osteogenesis is comparatively rapid, the bone wax is especially valuable if for no other reason than furnishing a kind of drain, but occasionally where drainage ceases it keeps the cavity filled until such time as osteogenesis has built sufficient new bone to obliterate the cavity from which the wax has been