contention, at the annual meeting in May last. The office of Licensed Embalmer was created. Proper regulations concerning the office, its duties and its limitations were enacted. These were heartily approved by the representatives of the State Funeral Directors' Association, at the head of which was the distinguished Hohenschuh. Under these rules some sixey-four applicants for the embalmer's license, of whom sixty passed, submitted themselves to a very rigid written examination, at our headquarters in Des Moines July 26th, and the movement is on. The other is that concerning tuberculosis, human and bovine. For several years past this comprehensive subject has had serious consideration of the Board. Due investigation and study, along both lines have duly been employed. Frequent reports on different phases of the subject have been given and conclusions have been reached, which are not unlike those reached by observers in other States, and which will be discussed at this meeting of the Conference. The public of Iowa, has as usual been kept apprised of our actions in this direction, by customary circulars of information, and a more elaborate summing of the question is now about to be put on the press, and will, when issued, be generally disseminated. Another thing we ought to mention: From its inception, the policy of the Board, within the circle of its influence, has been in the direction of the elimination of the idea, that in sanitary matters, at least, the broadest tolerance should not be cultvated, and that no one school in medicine should be preferred to another. The Board-as a Health Board-cares nothing for Pathies, as Pathies. In its opinion, sanitary science is wholly sectless. It holds that "a man's a man for a' that." It realizes the force and aptness of Paul the Apostle's axiom, which is the golden text of the gospel of toleration and unity, "There are, it may be, so many kinds of voices in the world, and none of them is without signification." It never engages in, neither does it countenance, within the lines of its duty, profitless discussions of medical creed titles, which always end where they began. Life is too short and too real for sensible men, nowa-days, to waste brain gray matter on such tom-foolery. Besides, we hold in reverence the wholesome doctrine, noblesse oblige, and to it conform. This total effacement of sectarian lines in non-partisan Boards, like our own, has been an educational object lesson to the profession at large and has done very much to lessen spoken and printed asperities in States where nonpartisan Boards exist under enlightened legislation. So, it is less frequent now than it was fifteen years ago, to see controversial medical asses, who certainly were boors instead of gentlemen before they were born by the breech into the profession; cavorting around with defiant chips on their shoulders; "biting their thumbs" at those with whom they differ and bravely flinging stink-pots at all and singular who decline, at their bidding, to look at facts and things and brother men through the reversed end of the telescope. In concluling: We are instructed to assure our conferees of the State and Provincial Boards here assembled, that Iowa yields to none in her desire that the entente cordiale, which has long subsisted between it and its honored sisters may long continue. She recognizes in them valuable helpers and experienced teachers, whose labors on behalf of the race she applauds and has sought to emulate, for they have been abundant and far-reaching and valuable beyond computation. In the give and take of friendly offices, and in the chivalrous rivalry "to see who best can work and best agree." Iowa has been no laggard. She is not built that way. To this conference of sister State Boards of Health, so long as it holds itself aloof from entangling alliances and remains sui generis, we shall come annually with our fraternal representatives, bearing the gifts of confidence and good will and honorable rivalship; asking nothing in return except a pledge that this body shall remain true to the traditions under which it was formed and "hold the faith in the unity of spirit;" that faith which is outlined in the axiom, which should be, but unfortunately is not, obeyed by all associations-"in certain things Unity; in doubtful things, Liberty; in all things, Charity.” THE PURIFICATION OF SURFACE WATER. BY GARDNER S. WILLIAMS, Detroit. The impurities in surface matters may be classed under five heads: Second-Dead organic matter-in suspension. Fourth-The microscopic organisms indigenous to the water. The processes applied for the purification of waters are straining, aeration, sedimentation, filtration, boiling and distillation, besides chemical treatment which is ordinarily applied in connection with one of the other methods, and each has its counterpart in the preparations through which the waters that are furnished for the use of man are passed in nature's vast laboratory. It is only within a comparatively recent period that this subject has received a much merited attention in America, or even abroad, and today there remain many erroneous ideas concerning its necessities and its possibilities. There are probably before me now those who repose faith in the ancient dictum that running water purifies itself, the amount of running necessary depending upon the distance of their particular water works intake from the nearest source of pollution. In the light of recent investigations no more misleading doctrine in connection with water supply was ever foisted upon an innocent and unsuspecting public, unless it be that chemical analysis alone is sufficient to determine the wholesome. ness of a water to be used for domestic purposes. These twin heresies, bred of the same original error, are so intimately connected that I will briefly consider them together. The impurities found in flowing water comprises certain inorganic or mineral substances in suspenson, usually harmless, and more or less decayed organic matter of both animal and vegetable origin, partly in suspension and partly in solution, in itself not dangerous, together with microscopic living organisms both animal and vegetable, and lastly bacteria, organisms so small that with the most powerful microscopes we can barely distinguish them. As an example, the typhoid bacillus magnified 1,100 times is not so large in body as our common house fly. The inorganic matter is made up of potash, soda, lime, magnesia, iron and alumnia in combination with chlorine and carbonic, sulphuric and silicic acids. The organic matters are composed of carbon, nitrogen, oxygen and hydrogen, animal matters containing more nitrogen and less carbon than vegetable matters. The process of decomposition in the organic matter takes place as follows: The carbon is first oxydized by the oxygen from the air mingled with the water, the resulting compounds being ammonia and carbon dioxide, next the ammonia is oxidized to nitrous acid and this is again oxidized to nitric acid, which combining with the mineral constituents, forms a nitrate and ends the process. So far as the condtions of this process are concerned the chemical anaylsis tells us with fair accuracy in what stage the matter in the water may be, but it fails entirely to indicate the presence of those minute living organisms which constitute the real source of danger in drinking waters. The results of a chemical analysis as usually given show 1, the quantity of chlorine; 2, the amount of so-called free ammonia; 3, the amount of albuminoid ammonia; 4, the amount of nitrites; 5, the amount of nitrates; 6, the amount of fixed residue remaining after heating to a dull red with sodium carbonate; 7, the loss by so heating, and 8, the amount of oxygen consumed when the sample is boiled for a fixed length of time with permanganate of potash. The chlorine, in itself harmless, if in excess of the normal quantity in waters of the particular locality, indicates previous sewage pollution. The free ammonia which, however, is almost never free as the hydrate but is ordinarily the chloride or carbonate, and the nitrates, harmless in themselves, indicate organic matter in a state of partial decomposition. As free ammonia is a prominent constituent of sewage, it has been claimed that this is an evidence of sewage pollution, but high free ammonia is often found in waters in which there is no possibility of sewage pollution, so we must only say that it indicates partially decomposed organic matter.* The albuminoid ammonia measures the amount of undecomposed organic matter, or more exactly the amount of nitrogen in it. The nitrates indicate completed decomposition, and are harmless in the quantities usually occurring. The fixed residue measures the mineral constituents and the loss on ignition is an indication of the volatile constituents. The quantity of oxygen consumed bears some relation to the amount of carbon present, but different substances behave very differently with the permanganate of potash, and hence this factor is only useful in comparing similar waters and has no significance with waters of dissimilar origin and nature.i So far as micro-organisms are concerned they are only indicated in the chemical analysis by a slight increase in the albuminoid ammonia which can in no way be separated from that due to partially decayed or dead matter. One of the best evidences of this is given by Prof. Frankland (Micro-organisms in Water p. 101-102), in an account of an examination of the River Dee in Scotland, which supplies Aberdeen with its water. The examination covered forty miles of river and beginning at the source the number of bacteria per cubic centimeter was first only 88, at the next point of observation they had increased to 2,829, at the next they had decreased to 1,139, then they increased again to 3,780, decreased to 938, increased to 1,860 and finally decreased to 950, and yet through all these changes in which the increases were uniformly caused by added sewage, Frankland says: "It was found impossible by means of chemical analysis to detect any material alteration in the composition of the river, even immediately below each of the above sources of contamination." The fact that chemical analysis does not indicate changes in the bacterial compositions of either sewage or water is shown by the following examples of analyses, taken at random from the report of the Massachusetts State Board of Health for 1891, and covering a wide range of conditions. * Rep. Mass. S. B. H. Water Supplies 1887-1890, p. 550; Rep. Mass. S. B. H. 1892, p. 319 et seq. Rep. Mass. S. B. H. 1892, p. 328. Prof. Drown discussing this subject, says: (Rep. Mass. S. B. H. Water Supply, etc., 1887-1890, p. 536.) "Students of sanitary science have attempted to establish certain standards of purity of water based on the determination of nitrogen. These standards express limits for organic nitrogen, or albuminoid ammonia, free ammonia, nitrites and nitrates, beyond which the water containing them should not be used for drinking. Some of them have the sanction of sanitary congresses, and some are merely the expression of individual opinion. The application of these standards of purity has condemned many waters which were certainly unfit to drink, but it is equally certain that many wholesome waters have been thereby rejected. The following table, another part of the same report (p. 541), brings out this point: Residue on Evap. 3.65 1.65 5 0.30 3.25 0.95 2.30 5.95 0.80 5.15 8.70 3.20 5.00 0.70 4.30 .0000 .0022 0.08 .0060 .0000 .0550 .0009 .0004 "The fallacy of making 'standards of purity,' continues Prof. Drown, "based upon the organic nitrogen, ammonia, nitrites and nitrates, is apparent when we consider that these substances are not injurious in themselves, at least to the extent which they are found in natural waters, and that the presence of any one of these substances in water does not in itself necessarily carry with it any indication of its origin. These standards are relics of the days in which the harmfulness of a water was supposed to be the direct result of the injurious action of specific substances found in it. The theory of to-day is that it is (in the large majority of cases) to the presence of micro-organisms in water that its harmful influence is due." Thus the chemical analysis is seen to be often insufficient to determine previous sewage pollution in water, and in the case of surface water it is often superfluous. As has been very pertinently remarked, "It does not need a chemical examination to decide whether a stream is polluted or not when one can see the sewage flowing into it." In determining the quality of a water supply every source of information bearing upon it should be investigated. The engineer should be called upon to ascertain all possible or probable sources of pollution, and the source of the water itself. This information should be given to the chemist who should then make his examination. The idea often prevalent in some communities that the way to get a fair result from an anaylsis is to keep the chemist in entire ignorance of the source of the water and everything about it, is most erroneous. While chemistry is an exact science and there is not likely to be much doubt as to the constituents found, the interpretation of results depends for its correctness on all the facts concerning the water being properly considered. Next the microscopist should be called upon to determine the organisms, vegetable and animal, that are recognizable with his instruments. These organisms may not be positively harmful but frequently give to the water disagreeable tastes and odors, so that their presence is not to be desired. Finally the services of the biologist should be invoked to determine the number and kind of bacteria in it, as from them oftentimes, though.it may be impossible to find the specific germ of any disease, it is possible to establish the probability of such specific germs being present. The chief, if not the only source of disease germs in water is animal sewage, and the number of bacteria in water, of all kinds, harmless as well as dangerous, may range from none to several thousand per cubic centimeter. The number in sewage being often more than a million. The number per gram (about one-thirtieth of an ounce Troy) in the feces of a healthy man ranges from as low as 10,000,000 to 200,000,000, while those of typhoid fever patients contain as high as 1,000,000,000. "If we assume that a man discharges about seven ounces of feces daily, this would give for typhoid patients 200,000,000,000 bacteria discharged daily per person" (Filtration of Public Water Supplies, p. 133). The number of bacteria found in sewage is usually higher, often double this: number per person. Not all, fortunately, of these bacteria are dangerous, perhaps ordinarily not more than one in two or three thousand, but the feces of typhoid patients contain the germs of that disease, and although in water there is no evidence that they, or any other diseasegerms increase, they retain their vitality for varying periods, and if granted favorable conditions will at once develop colonies of fellows. It is the possible presence of these latter organisms that renders chemical analysis fruitless for the purpose it has been so long considered final. The so-called self-purification of rivers takes place to varying extents in three ways. By dilution, by sedimentation, and by oxidation and light. The first means is by far the most important. The inflow of pure or unpolluted water below the point of contamination reduces the percentage of dangerous organisms in the stream. This inflow of purer water comes not only from visible tributaries, but from subterranean streams flowing into the river at all points, so that while there may be |