THE ANALYST. APRIL, 1895. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS. The monthly meeting of the Society was held the evening of Wednesday, March 6, at the Chemical Society’s Rooms, Burlington House, the President (Dr. Stevenson) occupying the chair. The minutes of the previous meeting were read and confirmed. hfr. D. J. O’Mahony, Public Analyst for Cork, was elected a member of the Society. Dr. Dupr6 read the following paper : NOTE ON THE CHEMICAL AND BACTERIOLOGICAL EXAMINATION OF WATER, WITH REMARKS ON THE FEVER EPIDEMIC AT WORTHING IN 1893. By A. DUPR$, Ph.D., F.R.S., F.I.C., Leaturer on Chemistry a t the Westminster Hospital Medical School. IT has long been known that certain diseases, as cholera or typhoid fever, were liable to be spread by water which had been contaminated by discharges coming from persons suffering from these disorders. I t is, however, only within coin- paratively speaking recent years that this liability of spreading disease was traced definitely to the presence of certain living organisms occurring in the discharges coming from persons suffering from these disorders.This having once been recog- nised, the conclusion was not perhaps unnaturally arrived at that a water could not be condemned as dangerous unless it contained some of these pathogenic organisms ; and chemical analysis, being unable to detect these, was condemned as useless. I t is because I firmly believe that such condemnation is unwarranted that I venture to bring this subject before you this evening. I need say but little about methods of analysis, but I cannot help drawing attention to the recent remarkable demonstrations of the difficulty connected with the carrying out of the organic carbon and nitrogen process devised by Professors Frankland and Armstrong.Those who have followed the analyses published monthly in the report of the official water examiner must have noticed that while Professor Frankland almost invariably gave the organic carbon higher than did Professors Odling, Crookes, and Tidy, the latter, almost as invariably, gave the organic nitrogen higher than Professor Frankland. The result was that the ratio between organic carbon and organic nitrogen, on which s t one time Professor Frankland pinned his faith in judging of the quality of a water was not infrequently twice as high in the one series as in the other, Here, then, we have74 THE ANALYST.- on the one hand one of the inventors of the process, a chemist of the highest repu- tation, whose experience of this method is certainly unrivalled, and on the other two of our foremost chemists, and the most enthusiastic convert to the process, differing month after month, and year after year, in this remarkable manner. What confidence, I ask, can we place after this in the process in the hands of chemists who cannot claim one-hundredth part of the experience of these observers ? Quite lately a change has come-in consequence, we are told, of some hints given by Professor Frankland -and the two series of analyses now agree very fairly. If Professors Dewar and Crookes are not above taking a hint from another quarter, I would advise them to discontinue their old unscientific method of estimating the oxygen absorbed from permanganate, and adopt the method now, I believe, very generally employed ; namely, the use of stoppered bottles, a temperature of 80" F., and four hours' action.For the purpose of this paper it does not, however, matter what particular method of analysis is adopted, provided it is carried out with care and skill. I will only add on this subject that in my opinion no judgment on any water should ever be formed on one or two analytical features only, but that as many points as possible likely to throw light on the subject should be investigated. For my part? I have for many years been in the habit of giving colour, smell, appearance (clear or turbid), deposit and character of deposit, nitrous acid, phosphoric acid, hardness before and after boiling, total dry residue, colour of the same and behaviour on ignition, oxygen absorbed from permanganate in four hours, sometimes also in fifteen minutes, chlorine, nitric acid, ammonia, albuminoid ammonia, and, only if specially desired, organic carbon and nitrogen.With the help of these data a just conclusion may, I think, be nearly always arrived at. The next point is, What does such a chemical analysis teach us? It does not, as before stated, show us the presence or absence of pathogenic organisms, or, indeed, of any living organism; and in this respect it is, of course, defective. (Examina- tion of the deposit by the microscope often teaches us a great deal, but is not a chemical examination).But it does show us, in ninety-nine cases out of a hundred, whether the water is polluted by sewage or not, particularly if we adopt the plan proposed by Mr. Hehner and myself-viz., comparing the water under examination with one from the same district and formation which the surroundings show to be unpolluted. n o doubt, if a water should be contaminated by a small proportion of, say, a typhoid stool, analysis may not be able to detect this pollution. Such a case, however, very rarely happens, except with artificially-prepared samples ; but if it should occur naturally, the analyst would most likely overlook it. I n nearly all cases, however, a polluted water mill contain the sewage from many healthy persons for that from one person suffering from typhoid, and although the latter by itself could not be detected, the sewage from the larger number of healthy persons can and will be detected.The fact of such pollution having taken place will-and this is a most important point-be detected, however perfect may have been the natural or artificial filtration, and it will of course be detected, whether any pathogenic organisms are present or not. Now we know that a water polluted by sewage, although at the time of analysis no infected sewage was present, may at any time become dangerous if anyone of theTHE ANALYST. 75 persons within the drainage area of the well should suffer from typhoid or cholera. The chemist is, therefore, able to anticipate what may happen in the future; and as no one will pretend that a sewage-contaminated water, even if free from pathogenic organisms, is wholesome, the chemist, by advising the closing up of a well or the abandonment of a watercourse, will close, so to speak, the stable-door before the steed is stolen. To put, then, the case of the chemist shortly : While unable to detect the presence of pathogenic organisms, he is, at any rate in the great majority of cases, able to detect the presence of sewage pollution.He is thereby able to anticipate what may happen in the future, and by timely advice prevent an outbreak of disease. He is, in some cases at least, able to detect the presence of pathogenic organisms in a water, but only after the water has become infected. When an outbreak has occurred, he will furnish the final proof that it has been caused by the water-a fact which, quite irrespective of such proof, would in nine cases out of ten have been demonstratcd by altogether inde- pendent investigation. The bacteriologist, of course, cannot find pathogenic organisms where they are not present, and has not, at least not in t,he same degree, the power of anticipating the future possessed by the chemist.He is able to close the stable- door, for conclusive reasons, but only after, not before, the steed has been stolen. I shall of course be told that in a sewage-polluted water the bacteriologist is able to detect numerous organisms non-pathogenic, but, like the bacillus coli, for example, characteristic of sewage. I answer, this may be so; but you condemned chemical analysis on the ground that it cannot detect pathogenic organisms, and you cannot run with the fox and hunt with the hounds. If you acknowledge that sewage- polluted water is not fit for human consumption, whether specially infected or not, you place yourself in the same position as the chemist, and the question will have to be decided, how can sewage pollution be most certainly detected, chemically or biologically? Do not, however, condemn analysis on the ground that it cannot detect pathogenic organisms, and then presume to judge a water, not by the presence or absence of pathogenic organisms, but by the mere number of the micro-organisms present.The proposal to condemn a water because it contains, say, more than a hundred micro-organisms per cubic centimetre appears to me to be simply nonsense.Take a deep well water, Kent water, for example, which in many instances, as it comes from the well, contains as few as ten organisms per cubic centimetre, or even less. Keep this same water for a day or two in moderately warm weather, and it contains thousands in the same volume. Are we to be told that Kent water is an admirable drinking water as it comes from the well, and absolutely unfit for drinking one or two days after? By means of biological examination we are probably better able to detect pollution in a water contaminated by unfiltered sewage; but this kind of pollution is, in well waters at least, comparatively speaking, a rare occurrence. I n most cases the sewage enters the well after filtration through more or less soil, in which many of the organisms remain behind.Experiments with artificially-polluted waters, in which the pollution is brought about by the addition of a small quantity of an infected stool, and without its proper complement of urine, are therefore greatly mideading. What, now, can the bacteriologist accomplish?76 THE ANALYST. They unduly favour biological examination as compared with chemical analysis. It would be extremely easy to prepare a water highly polluted by sewage, which, on biological examination, would have to be pronounced absolutely free from contamina- tion, but in which chemical analysis would reveal the presence of sewage with the greatest ease. Would biologists consider such an artificially-prepared water a fair sample to judge between biological and chemical examination? I am, of course, aware that there is at least one case on record in which, in all human probability, a single discharge from a person suffering from typhoid, polluting a well, caused a serious outbreak of typhoid.(We shall presently see that, according to Dr. Kelly, the typhoid outbreak at Worthing two years ago was a case of a similar character.) I n such a case bacteriological examination might possibly have succeeded in tracing the mischief to the well, while analysis would probably have failed. But biology would only have succeeded when it was too late to prevent mischief. Moreover, such cases are necessarily rare, and never ought to occur ; they cannot fairly be brought forward as proving the general superiority of biological examination over chemical analysis.I do not wish to be regarded as hostile to the bacteriological examination of water, but 1 do not believe that it can replace chemical analysis. I n many cases biological examination is, of course, of the highest value. Take the case of our London water-supply. We know that the Thames is largely polluted by sewage, which in many cases is infected sewage, and we do not as yet know sufficient of the life-history of these organisms to be justified in affirming that none will ever reach the intake of the waterworks, and find their way on to the filter-beds. Although, as far as I know, none have ever been detected there, their possible presence must be accepted. The safety of the supply depends, therefore, on the efficiency of the filtration.If, then, it can be shown that filtration is able to remove 99 per cent, of all the micro-organisms present, we are justified in concluding that the chance of pathogenic organisms finding their way into the filtered water is but slight. To judge the efficiency or otberwise of the filtration of such a water, biological examination is certainly a far more effective guide than analysis. But this case also shows tho weakness of biological examination. On the strength of it, we are forced to pronounce the water to be pure and free from pollution, whereas the chemist has no difficulty in pronouncing it sewage polluted. Armed with this knowledge, he is able to say : “This water is polluted by sewage, and although not in its present condition injurious, it may at any time, through a breakdown of the filtering arrangements, become dangerous.” Biological examination of water is yet in its infancy; but, judging by the great strides in advance it has made during the last few years, we may confidently look forward to further improvements in the near future.Nevertheless, it will not, in my opinion, ever be able to replace chemical analysis. Let me draw attention, in passing, to the conveniently small measure adopted by bacteriologists to record their results; namely, the number of colonies yielded by 1 cubic centimetre of water. Now, one organism per cubic centimetre means 4,543 per gallon, or about 300 in an ordinary tumblerful of water. Koch’s limit of 100 colonies per cubic centimetre means, therefore, 453,600 per gallon, or 30,000 per tumbler.How beautifully free from impurity would most water, or even sewage,THE ANALYST. 77 appear if we stated our analytical results in parts per cubic centimetre, instead of in parts per 100,000, per million, or in grains per gallon. Now, inasmuch as nobody can tell, at present, how small a number of pathogenic organisms may, say under conditions most favourable to their action, produce serious effects, this statement of organisms per cubic centimetre seems very unsatisfactory, seeing that many of US are in the habit of frequently drinking several pints of water a day. No doubt if the bacteriologist finds pathogenic organisms in a water, that water stands condemned, whatever its other qualities may be; but does the converse hold good? Are we justified in pronouncing a water as perfectly safe in which the bacteriologist has been unable to find any such organisms? Can we be sure that the cubic centimetre, or the litre, or the two litres he has examined contained their proper proportion of all the various organisms present in a large bulk of water? Do we know enough of the con- ditions of existence of these organisms to be justified in such a conclusion? What would be thought of a man who, if he, say, in ten cubic yards of sea-water found no fish, were to pronounce that there are no fish in the sea? or who, when he found a certain number of herrings in ten cubic yards in the midst of a shoal of herrings, would take this as a basis for calculating the number of herrings in the sea? The conclusion, then, that I have arrived at is that each of these two methods of exami- nation has its strong and its weak points, and that neither of them can fully replace the other.They should, if possible, be used in conjunction with each other ; but if one kind of examination only can be done, this one should be chemical analysis. I cannot conclude without making some remarks on the outbreak of enteric fever in Worthing in the spring and summer of 1893, as it offers a good example of the manner in which chemical analysis is often contrasted with bacteriological exarnina- tions, to the disadvantage of the former. Several chemical analyses of ' Worthing ' water, before, as well as after, the date on which the new supply was utilized, are given in Appendix B, and from these it will be seen that, as not infrequently happens, chemistry failed to detect any definit'e impurity in the water.But the result of bacterioscopic examinations, given in Appendix C, furnishes con- clusive evidence of contamination of this supply by fzcal matter. Let us see how the case really stands. The first case of enteric fever at Worthing was notified on May 3 (as subsequently ascertained, the first attack had occurred on April 16, between which date and May 2 fifteen more persons were attacked). The first sample of water sent to me was drawn on May 2 from just below the surface of the water in the well (well C), while the second sample was t'aken on May 6 from a depth of 57 feet below the level of the ground, 30 feet below the water-level, and 154 feet from the bottom of the well.At the time I was entirely ignorant of what had happened at Worthing ; but even now, with it full knowledge of this, I am still strongly of opinion that these samples, particularly that of May 6, were not polluted by sewage. The latter sample is chemically purer than average Kent waterworks water. On May 15 another sample of water was taken from the same well (well C), but this time froni the bottom, and close to the new heading, through which the pollution was supposed to enter the well. This sample was examined by Professor Dr. Theodore Thomson says (p. 17 of his report) : I reported both samples as unpolluted by sewage,78 THE ANALYST, Crookshanks, who found it to contain 118,000 bacteria per cubic centinietre.I n his report no mention is made either of bacillus coli or the enteric fever bacillus, and as the examination was made with a full lrnowledge of what had happened at Worthing, we must assume that none were present. On June 5 two more samples were taken from the bottom of well C. One sample was sent to Professor Crookshanks, the other to Professor Millar Thomson. Professor Crookshanks sums up his report as follows : “ The water-sample of June 5, 1893, ranks, from the bacteriological analysis, as very pure water.” Professor M. Thomson’s analysis shows the water to have been, on the whole, not quite as pure as my sample of May 6, but he reports : “ On the whole, the chemical analysis of the water sent does not point to the water being unfit for drinking purposes.” Here, then, we have three chemical analyses and two bacteriological examinations, none of which point to sewage contamination, the second bacteriological examination being, in fact, highly favourable.Let me repeat here that my second sample-the most important one-was taken 158 feet from the bottom of the well, and 94 feet above the crown of the suspected heading. I t was, therefore, in all probability, purer than a sample taken from the bottom would have been. Why are these two bacteriological examinations, made by an eminent observer, not mentioned in Dr. Th. Thomson’s report? Where, I ask, is the failure of chemical analysis as compared with bacteriological examination, for both methods point to the same conclusion ? On July 26 a further sample of water was taken from well C and sent to Dr.Klein. The depth froin which the sample was taken is, unfortunately, not given, but it was probably taken from the bottom of the well. In this sample Dr. Klein detected, apparently, five bacillus coli in the particulate residue from 2,500 cubic centimetre of water, driven through a Berkefeld filter. No enteric fever bacilli were detected in this sample. On August 2 another sample of water was taken at the Worthing Waterworks, this time drop by drop during twelve hours, from the rising main, through which the water from all the wells, headings, etc., passed. In 1,500 C.C. of this water Dr. Klein detected an abundance of bacillus coli, and three organisms, two on one plate and one on another, which on sub-culture presented morphologically, as well as culturally, all the characters of the enteric fever bacillus.” Observe, Dr.Klein does not say that what he found was actually the enteric fever bacillus, and he was evidently alive to the fact that; it might have been some other organism, otherwise why this caution? If a chemist were to state in his report that he found something which gave the reaction of, say, nitric acid, but did not say that it wa,s nitric acid, we should all know what to think of such a statement. Before finishing this part of the case, it is necessary to say that in Dr. Th. Thornson’s report, p. 16, it is clearly shown that under ordinary conditions no sewage would find its way to the near neighbourhood of the heading through which the pollution is supposed to have entered the well, but that when st heavy rainfall coincided with a tide-locked condition of the sewers, some sewage, by being backed up along an old disused overflow pipe, might find its way there, Now, during March and April, 1893, the rainfall at Worthing was 0.33 inches and 0.08 inches respectively, and for seven weeks prior to May 6 practically no rain at all fell, OnTHE ANALYST.79 the other hand, during June and July the rainfall amounted to 0.58 and 4.95 inches respectively, of which no less than 3.05 inches fell within ten days of June 26 and 0.41 inches on the 26th itself. Where, I ask, is the justification for comparing samples taken on May 2 and 6, at a time of little or no rainfall, and an epidemic only just beginning, with the samples of June 26 and August 2, after heavy rainfall and an epidemic only just past its height, after having run its course for over four months ? If such a conjunction of favourable circumstances is necessary to enable a bacteriologist to detect the presence of three organisms which on subculture presented morphologically and culturally all the characters of the enteric fever bacillus, all I can say is, save us from the bacteriologist ! But the case against bacteriology is not by any means exhausted with regard to this Worthing outbreak.So far I have only dealt with the outbreak at Worthing and other places, the water-supply of which was taken from the Worthing waterworks. There was, however, a similar outbreak at West Worthing, which has a separate supply. This outbreak was also traced by Dr.Th. Thomson to the water-supply, with this difference : that he believes, from the localization of the outbreak in certain districts of West Worthing, that it was due to local pollution of the water in the mains of these districts, and not to pollution of the water at the waterworks. Here, then, was a, fine field for the bacteriologist, who, moreover, as no chemist was employed, had the field all to himself. The result was that Dr. Klein was unable to detect the bacillus coli or the bacillus of enteric fever in either the water taken drop by drop during twelve hours from the rising main at the waterworks, or in the water taken from a tap in direct communication with the water-main in one of the worst stricken streets of West Worthing. It would be highly interesting if we knew what a chemist could have done. What does Dr. Th. Thomson say of this failure of his favourite instrument for water examination? After some remarks I need not quote here, he says : “ For specific organisms are usually present in water in small amounts only, and could readily be absent in the small samples selected for examination.” Precisely SO; this is exactly my view, But it is advisable to point out that here we have not only complete failure to detect the pathogenic organisms which must have been present in the supply, but also a total failure to detect the bacillus coli, the organism by help of which mainly the chemist was supposed to have been vanquished. I ask again, where is the justification for extolling bacteriology at the expense of chemical analysis ? I n conclusion, it may not be uninteresting to state that, in the opinion of Dr. Kelly, the Medical Oficer for Worthing, the outbreak was not due to any sewage pollution of the water in the ordinary sense, but was due, like tbe case at Caterham, to the misbehaviour of some of the workmen working in the new heading shortly before the outbreak began. Dr. Kelly wrote to me on October 4, 1894 : “ Chemistry failed to help us because, as a matter of fact, no sewage entered into our new water- supply.” My own opinion is, that the greater portion of the epidemic was due to pollution of the water in the mains of the town of Worthing just as in the case of West Wort hing. Any comment of mine is unnecessary.80 THE ANALYST. Dr. Thresh then read the following paper :