SCIENCE. 



[Vol. XIII. No. 334 



wash. By the method I shall give, and illustrate with specimens I 

 have with me, I will show that walls can be ornamented with any 

 degree of elaboration desired, or plain, and at much less expense 

 than with any of the old modes. The article has been sold for 

 some years, and I find it in use by most of the sanitarians I talk 

 with on this subject. 



We will now consider the prevailing modes a little further. It 

 is well known that most houses are papered, and that care has been 

 taken in most cases to choose dark papers with many figures, for 

 the same reason that a workman prefers a colored shirt ; and I 

 think I do not overstate when I say that seven-eighths of the build- 

 ings papered are papered more than once, that is, that two or 

 more layers have been pasted on, one upon another, and that a 

 large portion of these, say one-half of them at least, have from six 

 to a dozen lp.yers on. It seems as though people should only need 

 to be reminded of this nasty practice, saying nothing about its 

 effect upon health, to induce them to at least remove the old 

 coats of paper and paste, after they have become filled with filth, 

 before applying new coats. It is not necessary for me to explain, 

 what every person knows, that flour-paste will soon mould ; that it 

 is a ready absorbent of moisture and disease germs ; also that pa- 

 per is a very ready absorbent. They may not be aware, however 

 that the coloring and bronzes, which are pulverized metals, brasses, 

 etc., are only temporarily held upon the face of the paper with ani- 

 mal matter (glue), that soon decays ; and glue is the greatest ab- 

 sorbent of moisture, and the natural culture-ground for the germs. 

 If these little pests get sufficient heat while there, they will flourish 

 (and the rooms are sometimes very warm above the lines of the 

 doors and windows, with a moderate fire) ; and where repeated 

 coats of this paste, paper, and glue are applied, from which out- 

 door air with its purifying effects is excluded by the respirating 

 pores being sealed or strangled, the danger is much greater. The 

 glue soon rots sufficiently to allow the air or any friction to remove 

 small particles to which these germs have attached themselves to 

 float about the room unseen, until they lodge in the system of some 

 unsuspecting victim, whose physical condition is such that they 

 take effect ; then they still have the little particles of fertilizer with 

 them to help give them a start on their deadly mission. 



Dr. Henry B. Baker, secretary of our State Board of Health, has 

 shown us many different kinds of these little bacilli, some of which 

 he had printed cuts of, taken from photographs. He explained 

 how, by the aid of the latest improved microscopical instruments, 

 it was possible to distinguish these pests one from the other, — 

 those causing typhoid-fever from those causing consumption, etc., 

 — and explained how their growth can be watched, where they 

 have been caught on bits of moistened glue ; how they must come 

 to a certain state of maturity before they are dangerous ; and that 

 they do not then take effect unless the lungs, or other parts of the 

 body they strike, are in such a weakened or inflamed condition that 

 nature cannot expel them. 



The fact that these conditions do not always cause serious mis- 

 chief ; that some people do live in rooms the walls of which are in 

 a very unsanitary condition, and probably filled with vermin, con- 

 tagion, and filth, without apparent or immediate injury to them, — 

 causes many to think' that these claims made by the sanitarians are 

 without foundation, or not of vital importance, while they probably 

 suffer from these causes, more or less, which they attribute to hav- 

 ing taken cold, or to having committed some impropriety in eating 

 or overwork ; and when they become very sick, they flee to another 

 climate, if they are well-to-do, where they often recover, probably 

 by getting in a room not in so bad a condition, and return home 

 to have the old trouble return, and continue to breathe this slow 

 death-dealing matter, to save the expense of removing the filth 

 froin the walls, or because they do not believe or have not heard 

 the warning. 



Another unsanitary practice is what is known as kalsomining, 

 which is the covering of ceilings and walls with coats of inert pow- 

 ders and colors, temporarily fastened to the wall with the same 

 kind of animal matter used in coating wall-papers. This glue coat 

 also strangles the wall, but is not so bad as wall-paper, seldom 

 contains as much poison, and does not admit of coating so many 

 times without falUng off, though there is more glue in it (and it 

 rots sooner) to be set afloat. Another bad practice is the painting 



of walls with oil-paint, composed of lead, zinc, and colors mixed 

 with oils. This seals the pores of the walls more effectually than 

 does the kalsomine or wall-paper, but remains longer before it de- 

 cays sufficiently for small particles of the lead to be dislodged, 

 though it always gives off a slight smell of -paint, and when the 

 room has been closed it always has a stuffy or stifled smell, some- 

 thing as do also all rooms covered with many layers of wall-paper. 

 The painted walls can be washed ; but, even if washed frequently, 

 the fine cracks always found in walls will be washed full of filth 

 and the germs of disease, if any, in the room. 



The article or process I have referred to as being adapted to 

 making a clean, cheap, and sanitary coat for walls, is composed 

 mainly of sulphate of lime, known as gypsum or alabaster, which 

 has been calcined by subjecting it to great heat in retorts, or boiled 

 in large kettles until its water of crystallization is driven off, so 

 that, when water is added to it again, it will again take up its 

 original water of crystallization. This process is called " setting," 

 and takes place naturally in about seven or eight minutes, re- 

 forming a stone much like the original stone in the quarry, but more 

 porous. This rock in thi natural state, as we grind it at Grand 

 Rapids for use on farm-crops, contains from 35 to 40 per cent of 

 sulphuric acid. The better grades of this rock, after calcining, are 

 so manipulated in making this article for walls, which is known as 

 alabastine, that this setting process is retarded for a number of 

 hours, adapting the plastic, or liquid, to being spread upon walls 

 with a brush in a very thin condition ; so that fifty coats, as applied 

 to walls from tirr^e to time, form a hard, porous shell not thicker 

 than card-paper ; and the coat is not of a glue or paste nature, the 

 size and admixtures used to retard the setting having been ab- 

 sorbed by the base in taking up its water in setting. There is only 

 one other article on the market that is claimed to produce the ef- 

 fects produced by alabastine, and that is called " anti-kalsomine and 

 plastico." These articles are made in many shades, ready for the 

 brush, by adding water. Many kalsomines are put up and sold in 

 the same form, but are dependent on glue to hold them to the 

 walls. 



The late Richard A. Proctor explained, in one of his last contri- 

 butions to the Inter-Ocean, how much moisture, in tons, would be 

 thrown off by respiration from an audience of a certain size in a 

 given number of hours. That this moisture is condensed mainly 

 on the walls of the room, is easily seen by rubbing the finger on 

 almost any painted wall, v^fhere the moisture does not penetrate 

 readily, but is on the surface, as is often seen on windows. This 

 is sometimes seen on paper and kalsomine ; but they absorb moist- 

 ure so quickly that it does not show on the surface, though they 

 attract more than the paint. That this moisture carries contami- 

 nation with it, is certain ; also that it rots such materials. The 

 paint, as explained before, is not quickly rotted, but oxidizes slowly, 

 so that the effect from it is not so bad as from paper or kalsomine. 

 That air passes through walls is proven by the dust-marks seen on 

 plastered walls, or those that hS.ve been only whitewashed or ala- 

 bastined, indicating the spaces between the lathing caused by the 

 dust being filtered from the air more between the laths than on 

 them. 



It should be borne in mind that it is not claimed that the amount 

 of air that will pass through walls the pores of which have not 

 been strangled, cuts any considerable figure in furnishing air to the 

 inmates of the room, but that this purifying of the ceilings and 

 walls takes place by the constant passing of pure air through and 

 through them, oxidizing, or practically burning, these little germs, 

 as it is well known pure air will do. In one of Professor Kedzie's 

 lectures, he cites experiments made by Professors Marker and 

 Shultz, in which they prove that a difference of 20 degrees in tem- 

 perature on either side of a wall of brick and mortar would cause 

 8 cubic feet of air to pass through each yard of such wall every 

 hour. 



I have some samples here of the sanitary coating I have referred 

 to, applied on panels, showing sections of quite elaborate designs, 

 as well as plain work. I will- explain them. This panel I now 

 show you is finished mainly in what is called reUef-work. This 

 corrugated work on the lower portion is done by applying the ala- 

 bastine thick ; then a coarse graining-comb was drawn through it 

 in various shapes, before it set. The colors having been ground 



