sanitarian has learnt that it is possible to mitigate the severity of the visit; and that, whether these evils arise from the occult causes to which I have alluded, or from other causes, pure air and pure water afford almost absolute safeguards against most forms of zymotic diseases. In speaking of the pure-water question, he remarked: Although there are many theories as to how far water which has once been contaminated by sewage may again after a time become fit to drink, I am disposed to think that there has never been a well-proved case of an outbreak of disease resulting from the use of drinking water where the chemist would not unhesitatingly on analysis have condemned the water as an impure source; and it appears probable that, whatever may be the actual causes of certain diseases--i.e., whether germs or chemical poisons, the _materies morbi_ which finds its way into the river at the sewage outfall is destroyed, together with the organic impurity, after a certain length of flow. He pressed that there should be no further delay in bringing the Act for the Prevention of Pollution of Rivers into operation, and in enforcing the provisions of the Acts. In regard to the pollution of the air, he called attention to the fact that nearly fifty years ago Mr. Edwin Chadwick impressed upon the community the evils which were caused by the impure condition of the air in our towns owing to the retention of refuse around houses. The speaker remarked that the gases, which were the result of putrefaction, were offensive to the smell, and some of them, such as sulphureted hydrogen, when present in undue proportions in the air, would kill persons outright, or when those gases were in smaller proportions in the air breathed by people, there would be a lowered tone of health in the individuals exposed to them. Continued exposure might lead to the development of other conditions, which, in their turn, might lead to disease or death. From this point the President proceeded to speak of the increased toxical power of volatile compounds given off by neglected decomposed matter, and was thence led to dwell upon the dangers arising from decomposed substances in cesspools and in badly constructed drains. There was no doubt, he said, that in the sewering of towns want of experience in the construction of works had in some cases led to deposits in the sewers, and evil consequences had ensued; but it might be accepted as certain that in every case where the sewerage had been devised on sound principles, and where the works had been carried on under intelligent supervision, a largely reduced death-rate had invariably followed.