In the examination of water the microscope has also been of great sei-vice 

 of late years ; and here, again, whilst there is much to afford individual 

 microscopists interesting and useful work, still it is so absolutely necessary 

 that our water supplies should be systematically examined regularly by the 

 most refined methods known, that the use of these methods by sanitary 

 authorities should be far more general than it is at present. (Examples of 

 work done by Dr. Percy Frankland with London water and by Government 

 sanitary departments in America were given.) The examination of the 

 water of any locality shows at different times much variation in the character 

 of its micioscopic inhabitants, and, as has been shown by researches by 

 Sir T. Leone and others, important changes are induced in water by the 

 development of bacteria. Some investigations have been made on the 

 vitality and multiplication of pathogenic organisms present in or purposely 

 inti-oduced into various waters, but the results are not sufficiently concordant 

 to draw conclusions from, and these very important investigations require 

 much further careful study and work. Amongst other results recently 

 reported are some bearing upon the turbidity of some waters owing to the 

 presence of micro-organisms, and a very interesting case is mentioned by 

 Dr. C. O. Harz, who, in examining the waters of the Schliersee, in Bavaria, 

 when it was covered with ice, noted a dense turbidity, at first of a green or 

 blue tinge, but becoming yellowish-red or a peach colour before finally 

 disappearing, and this was chiefly due to enormous quantities of a palmetta, 

 which was attacked and finally completely destroyed by a peach-coloured 

 micrococcus. 



Another practical purpose to which the microscope may be put is in the 

 examination of foods, and especially in connection with the preparation, 

 transit and storage of preserved and other foodstuffs now so largely imported 

 from abroad. Also, it is serviceable in detecting sophistications of foods 

 and drinks, and continually is the microscope adding new means of detecting 

 adulteration. (Some new results in detection of mixed fats in butter, &c. 

 were shown). 



Microscopy is again useful in noting the characters of fibres used in 

 textile manufactures, and for cordage, paper-making, &c. and so important 

 has this been considered in America that there was formed there in 1885 a 

 National Textile Microscopical Association. Not only can the microscope 

 give useful information respecting the natural characters of fibres and the 

 changes they undergo during treatment, but it can also give much valuable 

 aid in connection with the dyeing and colouring operations they are 

 subjected to. 



In agriculture, also, the microscope is of great use. Even as regards the 

 soil it has, by studying micro-organisms, taught much respecting the 



