Twelfth Congress of the International Association of Limnologists.

THE Twelfth Congress of the International Association of Liinnology, of which Dr. Gunnar Alm' of Sweden is president, will be held in Cambridge, England, at the Windermere Laboratory of the Freshwater Biological Association. The Congress will open late in the afternoon of August 20 and continue through August 30. Preparations have been in the hands of the Organising Cominittee, with Professor F. E. Fritsch as Secretary. The scientific sessions, which will be held at Cambridge, are each divided into two or more groups, dealing respectively with the theoretical and applied sides of limnological science. To a considerable extent the papers to be read, of which approximately 100 have been offered, are grouped as symposia relating to such main topics as exchange and circulation in lakes, productivity in fresh waters, ecological and historical aspects of distribution, freshwater plankton problems, problems relating to freshwater algae, introduction of foreign species, pollution and its effects, especially in relation to fish, waterworks problems, and problems arising in connection with the treatment of sewage. There will be two evening discourses. On August 21, Professor d'Ancona (Padua) will deliver the first Edgardo Baldi Memiiorial Lecture on "The Stability of Lake Planktonic Communities," and on August 25, Lt.-Col. Mackenzie, Director of Water Examinations, Metropolitan Water Board, London, will speak on "The Reservoirs of the Metropolitan Water Board and Their Influence upon the Character of the Stored Water." On the evenings of August 22 and 24, there will be displays of relevant scientific films. On the first evening at Cambridge there will be a reception at Trinity College, and on the afternoon of August 25, a garden party at Christ's College. The journey from Cambridge to Windermere is to be made by coach and will occupy three days (August 26-28). The theoretical and applied groups of members will follow different routes, and each will visit a number of institutions or localities of special interest on the way. At Windermere one day will be occupied by an inspection of the laboratory and a visit to the experimental hatchery and fish ponds of the Freshwater Biological Association, as well as by demonstrations of work on the lake itself, while the other will be devoted to one or another of a number of alternative tours of the Lake District. The final session of the Congress will take place on the evening of August 30. A considerable number of excursions have been arranged. A small group of members will visit various localities of limnological interest in the south of England prior to the opening of the Congress. At Cambridge there will be excursions to Wicken Fen, the Norfolk Broads, and, for the applied section, visits to a sewage disposal works and the Water Pollution Research Laboratory. After the termination of the Congress, there will be a four-day excursion in Scotland and, subsequent to that, a week's tour in Ireland.