The hundreth anniversary of the birth of Mendel was celebrated in Brunn on September 23 last. The Government of Czecho-Slovakia placed generous funds at the disposal of a local committee, which arranged the centenary celebrations with the liberality and efficiency that we have learnt to expect from the new Czecho-Slovakian state. Credit is especially due to the committee for having made the centenary an occasion for bringing together, for the first time since the war, geneticists of all lands, the visitors comprising representatives of America, Austria, Denmark, England, Finland, Germany, Holland, India, Japan, Jugoslavia, Norway, Poland, Sweden, and Switzerland. The official proceedings opened with a visit to the monastery in which Mendel had lived, and to the adjoining garden in which he made his experiments. Wreaths were laid before the monument of Mendel which was erected in 1910, and speeches were made by the chairman of the local Naturwissen-schaftlicher Verein, by the official representative of the Government, by the Burgomeister, by Prof. Erwin Baur (Berlin), Prof. Chodat (Geneva), Prof. NSmec (Prague), Mr. S. Pease (Cambridge), and Prof, litis (Brunn). At the luncheon which followed, the principal speaker was Prof. Wettstein (Vienna), who emphasised particularly the international significance of the event. Prof. C. B. Davenport (Washington) replied, and the official proceedings terminated with a speech by Prof. Richard Hertwig (Munich). In the evening, a special performance was given at the opera, to which the guests were invited: it was the first occasion in Brunn on which the works of Czech and German composers had appeared on the same programme, a matter locally of much comment and great importance. The next day an expedition to recently discovered and very remarkable caves in the Moravian Karst was arranged. It is to be hoped that the success of this gathering will encourage others to organise congresses that are international and not merely inter-allied, in order that the friendships and intercourse which the war destroyed may be once more built up.