126 



POPULAR SCIENCE NEWS. 



[August, 1889. 



[Original in The Popular Science Neivs j 

 WATER-SUPPLY AND WATER POLLUTION. 



BY JOHN CROWELL, M. D. 



Watisr is such an essential element in the animal 

 economj, and so nearly affects every department of 

 domestic life, that its purity is of vital importance. 

 The literature touching the various phases of water- 

 supply is so abundant, that it is difficult for the 

 casual reader to gather the few fundamental facts 

 that bear directly upon the practical uses of water, 

 and the appliances which modern ingenuity has 

 devised and adapted to the modes of inodern life. 

 The refinements as well as the necessities of our 

 civilization have essentially changed the questions 

 of water-supply and the disposal of sewage. The 

 purity of the one, and the safe management of the 

 other, are so nearly related that both must be con- 

 sidered together. Modern methods of sewerage 

 cannot be made practical without a good water- 

 supply, and pure water cannot be had without free- 

 dom from the contamination of sewage. Of course 

 the purity of water depends upon the purity of the 

 substances with which it comes in contact. If rain- 

 water is gathered in a basin or tank, those recepta- 

 cles must be free from any sources of contamination. 

 If the roof of the house is of slate or clean shingles, 

 and the tank or cistern free from filth of any kind, 

 the rain-water thus gathered will be pure. But all 

 water collected in tanks, ponds, lakes, or reservoirs, 

 will be pure or impure according to the condition of 

 the water-shed, or of the receptacle containing the 

 supply. The conditions to be considered in every 

 water-supply are : the character of tlie soil through 

 which it passes, the dangers of pollution from sub- 

 soil drainage, and the contamination from inflowing 

 streams of filth along the banks of the river from 

 which the supply is taken. Deep wells and subter- 

 ranean springs are generally pure, if not excessively 

 charged with mineral salts, but even these sources 

 are often contaminated by pollution from some hid- 

 den and unexpected stream, and are sometimes the 

 cause of endemic disease. 



The effects of impure water vary according to the 

 impurity. When the mineral substances do not 

 exceed 17.5 grains to the U. S. gallon, and do not 

 give a taste to the water, it may be considered safe 

 without further analysis. 



The question of the use of leaden pipes in the dis- 

 tribution of potable water has always been of 

 interest to the public, but instances of poisoning 

 frorn such appliances are very rare. The practical 

 fact which interests the users of water conducted 

 through leaden pipes is, that when mineral salts 

 are present in the water, their action with the lead 

 causes an insoluble coating upon the inner surface 

 of the pipe, which forms a protection against all the 

 harmful effects of lead-poisoning. It is well, how- 

 ever, when lead is used for service pipes, to open 

 the faucet in the morning and let the accumulated 

 water run off before drawing a supply for family 

 use. No matter what may be the chemical constit- 

 uents of the water, the contact with the service lead 

 pipes during a constant flow is so slight that no 

 harmful results will follow from their use. Lead 

 cisterns are not so safe, and, should any metal be 

 employed, iron is the best, but this, according to 

 Professor Nichols, should be protected by a coating 

 of asphalt paint or black varnish. 



Zinc is acted upon by most waters, but, according 

 to the best authorities, the corrosion is not active 

 unless the coating is imperfect. Dr. Downes, of 

 Chelmsford, England, and Dr. Boardman, of Bos- 

 ton, both arrived at the same conclusion in their 

 careful experiments, that the action of zinc upon 

 water does not materially endanger the health of 

 those who make use of the water for drinking pur- 



poses. [Other investigators of this point have 

 arrived at an opposite conclusion. — Ed.] 



The question of the contamination of rivers by 

 the inflow of the sewage of large cities is of great 

 importance, and has given rise to a careful investi- 

 gation by scientists the world over. Does river- 

 water purify itself from the sewage received from 

 the drainage of cities, so that the water becomes fit 

 for potable use.' Prof. A. R. Leeds contends, by 

 his own experiments, that the waters of the Passaic 

 river, in receiving the sewage of Paterson, becoiue 

 eminently fit for use before they reach Newark. 

 And he contends that this water, when furnished to 

 the consumer at Newark, is of better quality than 

 before it became polluted ! 



The experiments of Dr. Ranch, of the State Board 

 of Health of Illinois, as given in the Report of 1886, 

 are full of interest. He contends that his laboratory 

 investigations show that the sewage of Chicago, in 

 its canal passage of thirty-three miles, is so nearly 

 divested of all contaminating qualities, that, if ex- 

 tended a few miles further, it would be entirely free 

 from all vestige of sewage. The conclusions of Dr. 

 Ranch are not considered as final, as other experi- 

 ments, upon a more extended scale, in the waters of 

 the great western rivers, which receive the sewage 

 of large cities, show that the absence of contamina- 

 tion is due more to the immense dilution of the 

 sewage than to any chemical action resulting in 

 self-purification. 



The English River-Pollution Commission, in the 

 report of their extended experiments in the rivers of 

 Great Britian, expressed the opinion that, while 

 many contend that running water becomes purified 

 in its flow, there was not a river in England of 

 sufficient length to warrant the oxidation and de- 

 struction of any sewage that might be received, even, 

 at its source. This is a subject of vital moment, as 

 most large cities depend upon rivers for their water- 

 supply, which rivers also receive the sewage of the 

 cities and towns along their banks. Some very 

 interesting statistics have been collated, which bear 

 upon the vital issues of the question. The city of 

 Brooklyn, N. Y., uses water which is, perhaps, less 

 polluted by sewage than that of any other city in 

 the country, and in 1885, ^3 pcsons in every 100,000 

 died of typhoid fever. In New York, where the 

 water-supply is guarded with care, the rate of deaths 

 from typhoid was, in the same year, 21. For the 

 same year, Boston is recorded as 38; Cincinnati, 

 44; Philadelphia, 44. These figures are significant, 

 inasmuch as the waters of the last three cities men- 

 tioned are more or less polluted, and the death rate, 

 as compared with that of Brooklyn, is emphatically 

 striking. 



It is a curious fact that New Orleans, with the 

 reeking filth in its streets, with no sewers and no 

 strict sanitary regulations, has a lower death rate 

 from typhoid than the sewered cities of the North, 

 it being, in the year 1885, only 16. But this result 

 is owing, not to the lack of sewers, but from the 

 fact that New Orleans receives its water-supply free 

 from the contaminations of sewage. The waters of 

 the Mississippi are pumped up chiefly for flushing 

 the streets, while the water-supply for domestic use 

 consists of rain-water stored in cypress-wood cis- 

 terns, which preserve it from all suspicion of pollu- 

 tion. Stored waters undergo purification from the 

 subsidence of their suspended matters, yet they are 

 liable, especially in summer, to become affected 

 with a vegetable taint, which sometimes produces 

 diarrheal troubles. Several of our great cities have 

 been troubled, from time to time, by the bad taste 

 of the waters in cisterns and reservoirs. In 1859, 

 the Croton waters were affected by a bad taste and 

 odor. In 1881, Prof. Remsen was called upon to 

 examine the cause of the disagreeable odor and 



taste of the Boston supply, and he referred the cause 

 to the presence of a large quantity of fresh-water 

 sponge, in a partially decayed condition. Boston 

 water is not yet free from the fishy taste caused by 

 this or some other conditions of the Cochituate 

 supply. So great is this defect that many private 

 families and most of the first-class hotels obtain 

 their table supply from some of the numerous pure 

 springs in the city suburbs. 



Apparatus for filtering has been applied to most 

 of the great systems of water-supply, and generally 

 with good results. A filtering basin has sides of 

 solid masonry, with floors of brick laid in hydraulic 

 cement, with channel ways for the collection of the 

 filtered water. The filtering medium consists of 

 several layers of broken stone, screened gravel, and 

 sand, the coarser material at the bottom and the 

 finer at the top. Filter-beds are often constructed 

 of gravel, or coarse sand. The city of Poughkeepsie 

 was the first to construct filter-beds for tlie purifica- 

 tion of the water-supply. These beds were made of 

 layers of stone of varying size, topped with gravel 

 and sand. The great expense attending the con- 

 struction of these beds has prevented their general 

 adoption in this country. The English make use 

 of beds of sand for filtering. Experiments showing 

 the relative purity of filtered and unfiltered water by 

 the sand process, reveal the fact that, in the unfil- 

 tered waters of the Thames, in the month of March, 

 18S6, there were found in each cubic centimetre 

 11,415 microbes. In the filtered water the propor- 

 tion was strikingly less. 



Domestic filters are largely in use, and they sub- 

 serve a most excellent purpose. These filters need 

 proper adjustment and constant care as to cleansing. 

 The Newark filters answer a good purpose in clear- 

 ing the water when it is made turbid by clay or fine 

 silicious particles, which choke the ordinary appli- 

 ances. Science is bus^' in devising ingenious 

 methods for the protection of the public from the 

 deleterious influences of impure water. With an 

 advancing civilization, and the attendant refinement 

 of domestic living, with all the complications of the 

 "convenience.s" of domestic life, it is a relief to 

 know that the benign hand of the investigator is 

 constantly at work devising means for diverting 

 evil, and protecting the eager multitudes that 

 throng the great centres of traffic from the dangers 

 that attend the introduction of every new appliance 

 that caters to the refinements of luxurious livinsr. 



[Specially Conipiltjii lor The /'oputar Science Aews.\ 



MONTHLY SUMMARY OF MEDICAL 



PROGRESS. 



BY W. S. WELLS, M. D. 



Dr. a. Mi:eller, of Victoria, communicates to 

 the Australasian Med. Gazette an article on the cure 

 of poisonous snake-bites, by hypodermic injections 

 of liq. strychniie. He says : 



"The diagnosis of snake-poisoning is not, in every 

 case, as easy as it may appear to the uninitiated. 

 No doubt, of course, remains where the snake has 

 been seen to strike, or even to bite and hang on to 

 the bitten limb, and where the symptoms are fully 

 developed. But frequently the srfake is not seen to 

 have bitten, but its proximity excites such terror as 

 to simulate the symptoms of snake-poisoning. 

 Terror, alone, has been known to cause death. The 

 influence of terror and snake-poisoning are both 

 capable of causing paralysis of the motor nerve 

 centres." 



Dr. Mueller calls attention to a fruitful source of 

 error that has cost many human lives, viz. : That 

 poisonous snakes, under all circumstances, leave 

 only two punctures, and that in any alleged case of 

 snake-bite, showing more than two punctures, we 

 may safely infer and rest content that it was not 



