the paper just read, he should have been glad indeed if he could say he agreed with Dr. Odling's conclusions. The meeting, however, would have been in a much better position to discuss his conclusions if they had been put in print, and he was sorry that this had not been done, as they were in fact, the most important part of the paper. He was so far in accord with him that purity, as expressed by chemists, had a very different meaning to that attached to it by the public, and he hoped Dr. Odling would, in future, say that they must not take the purity of the water as he set it forth in his reports, to mean absolute purity and freedom from unwholesome conditions, that is from organic germs, freedom from what medical men knew to be deleterious to human life. Dr. Odling had said that the pure water of the Kent Company contained more organic matter than the water of the Thames; this appeared to be a fiction-a chemical fiction; and Professor Frankland, who originated the previous sewage contamination theory, now put it aside, and told them it had no value whatever; in fact, it had so little value, that it merely expressed something that chemists understood, and the public did not. The public were not in a fair condition to say what the chemist meant, but they know what they wanted, they wanted water perfectly free from all organic impurities, and if they got that, they cared little whether it was one grain or a dozen grains of mineral matter to a gallon. The one grain, however, which some chemists despised, was more than sufficient if it contained a specific germ, as that of typhoid fever or cholera, to poison a whole town of 40,000 inhabitants. What more did chemists require in the way of impurity? Chemists could tell us of the impurity of water; but they could not assure us of purity and safety. Chemistry could not detect the millionth, or trillionth, part of a grain of deadly organic matter in a gallon of water. That being so, it showed that chemists could only very imperfectly perform the duties undertaken by them; they could not protect the public health, as they had sometimes been led to assert. Dr. Odling had referred to the

Registrar-General's reports of June; but he had in his hand later reports, those of July, also issued from Somersethouse, and with regard to three or four towns supplied with deep well water, he noticed that Brighton had a death-rate of 139 to the 1000; Hull 19 to the 1000; Portsmouth 14'I to the 1000; whilst London had 24 to the 1000. That showed that there was a considerable difference in the death-rate of towns supplied with pure and wholesome water, such as he held deep well-water to be. In London with the rise in temperature, during the month of July, there was a corresponding rise in the deaths from diarrhoea and dysentery; there were 39 in the first week, then 104 in the next, and 336 in the succeeding week. In the next month they rose again to 533, exceeding the corrected average by 242-435 were of infants under one year of age, and 78 of children between one to five. There was usually a considerable difference in the death-rate whenever the temperature of water ranged above 60 degrees, then it was that the danger of an impure drinking water was greater. He had placed on the table two specimens of deep well-water from Canterbury, one taken before being submitted to a softening process, the other after it had been softened by Clark's process. The deposit thrown down he had examined under the microscope, and could find no trace of organic matter, not even a diatomaceous body, which he expected to find under a high power.

MR. EDWIN CHADWICK, C.B., said the chemical tests for water omitted altogether what was called the biological, or stomach test, of which he might give a remarkable instance that was that there was a change in the supply of water of the Millbank Prison from the Thames, which had formerly been used, to that of the well at Trafalgarsquare, and there was a return by the medical officer of the prison, in which he showed the difference produced in the population by this change. The evidence of the benefit resulting from the change was perfectly overwhelming. In Glasgow, Aberdeen, and Manchester, all the water was

found to produce dyspepsia, which chemists did not detect or take account of, but it was perfectly decisive as to the quality of water, especially during particular portions of the year. He thought it would be well if the investigation as to the sanitary results were pursued by asking the officers of prisons to note the difference produced in the health of the prisoners by a change of water; those who have been for a time in a hard-water district, and those who were in a soft-water district, and he had no doubt that result would be obtained similar to those recorded in the instance he had referred to at Millbank, and which were utterly unnoticed by any chemist at present. Again, the Chairman would know very well how the quality of water depended on its aëration. At Pangbourne you might take up water, and find it quite brilliant, showing evidence of good quality, but when that same water was taken to London, and put into a cistern where it came in contact with the air of the cistern, your were really drinking down air with all the impurities which were likely to arise. In going into overcrowded rooms, or low neighbourhoods, medical officers would tell you that in washing, after an operation, their fingers quite smelt of the water they obtained there. He recollected on one occasion, when making an inspection in Rotherhithe, the medical officer cautioned him against taking any water there, for it would be dangerous, because the water beds were situated close by the cesspools and absorbed the cesspool air. Some years ago, he asked Dr. Hofmann if he could analyse a London fog, which carried disease with it; but he could only separate the dust and dirt, and he failed to analyse them. Again, with respect to the paper which spoke of the protection of rivers by the action of plants, he would point out the immense difference between fresh sewage and that which was putrid. When the houses of a town were drained, or water-closetted, so that the sewage discharged fresh, it was noticed that fish returned to the river which they had forsaken. That had been noticed at Carlislethe fish reappeared, and were finer in quality altogether.

Mr. BISCHOF said it had been a point of the greatest interest to him to learn that spongy iron, after a very few minutes' contact, had such a powerful effect in destroying animal and vegetable life. Mr. Anderson had said that his anticipations at Antwerp were not quite fulfilled, and that was quite true; but he never anticipated the difficulty which had been experienced there. To deal with a small tidal river contaminated with all kinds of polluting matter, and to convert such water into a potable water, every one would admit was a matter of the greatest difficulty. However, the plan introduced by him had been styled a "complete success" by the Chairman of the Antwerp Waterworks Company, at the last general meeting. Dr. Odling had been speaking under great difficulties as regards time, no doubt; but to him, as a chemist, it would have been of much interest if he could have given some. hint as to how he arrived at the statement that organic matter in water might be said roughly to contain 40 per cent. of organic carbon. As a chemist, he could scarcely conceive that there should not be an enormous difference in different organic matter, because some water was contaminated largely-in fact, almost exclusively-by animal and other water by vegetable matter, and they all knew that animal and vegetable matter differed very greatly in the proportion of carbon they contained. He wished to refer to only one more point. He had in his hand the return of the Registrar-General for July 20th, 1878, which stated: "The weekly deaths from diarrhoea and simple cholera, which had been 23, rose to 78, 156, 256, and 349 in the corresponding weeks. The deaths from diarrhoea are differently distributed in the fields of the water companics. Thus, the deaths in the last four weeks were 786 in the districts supplied with the Thames and Lea waters, whereas the deaths in the districts supplied with water drawn from the chalk by the Kent Company were 19; but of the same population, the deaths in the former were to the deaths in the latter as 3 to 1." As there might be a visitation of cholera this autumn, and as they all agreed

that diarrhoea and simple cholera, although totally distinct from Asiatic cholera would still predispose to it, this was a point of very great interest, and he should be glad if Dr. Odling, or any one else, would express an opinion whether these figures which he had just read did not throw an important light on the relative wholesomeness of the different supplies of water to the metropolis.

Dr. BARTLETT said, one observation made by Dr. Odling very naturally led up to the few words he had to say. He stated that certain water, when thoroughly filtered, would then be good enough, and pure enough, for all potable purposes; another leading observation was made in Mr. Anderson's paper, namely that by mixing iron in a very finely powdered state with water, a far greater efficacy was obtained than can be in the ordinary way, by passing it through coarse filter beds or compressed blocks of porous iron or other filtering substances. He so far cordially agreed with that statement that it formed the very pith of what he wished to say. At the present time the question of filtration, whether in the water companies' sand-beds, or in the domestic filters which persons now used for the purpose of correcting any omissions on the part of the companies, was highly prominent. One section of the public appeared to rely entirely on this process, and another semi-scientific section were apt to place no reliance whatever on it. It had been stated, over and over again, that filtration could not remove matters in solution, but only those in suspension; but to that statement he took objection, because during the last ten or fifteen years, in the process of testing a great number of filters-in fact, almost every kind which was presented to the public-he had found, that to a lesser or greater degree, nitrogenous matters in solution were removed. The manufacture of filters, and the scientific application of filtering media, had improved, but although he said this with great confidence that there were filters which would remove nine-tenths of the nitrogenous matters in solution, still, he was equally certain that nine-tenths of the filters before the public were perfectly worthless, because with