The International Congress on Tuberculosis was a series of major congresses held between 1899 and 1912 in which scientists and physicians exchanged information on tuberculosis, a significant cause of death at the time. 1899 congress (Berlin) The first International Congress on Tuberculosis () was held at Berlin on the 24–27 May 1899. The congress was opened by Victor II, Duke of Ratibor in the presence of the Empress of Germany. The congress was held in the Chamber of the Reichstag. Various papers were read on the nature of tuberculosis in man and animals, its diagnosis, pathology, and preventative and curative treatment. Most of the speakers were German. There was no general discussion, but the published proceedings were expected to be valuable. About 180 delegates represented different governments, universities and other public bodies. About 2,000 members attended the sessions, whose purpose was mainly to instruct doctors, officials and the general public. The speakers explained aspects of the subject and the actions that should be taken to prevent the spread of the disease and to treat it when present. It was known by this time that tuberculosis was caused by a bacillus discovered by Professor Robert Koch of Berlin. Infection was thought to usually be passed by phlegm coughed up by a sick person, dried into dust and then inhaled by a healthy person. It was thought that tuberculosis "is not 'catching', in the popular sense of the word. The disease is not conveyed by the breath, nor even by coughing, except as a rare exception." Milk was known to be an important means of infection, and eating poorly cooked contaminated meat could also cause infection, although rarely. Means of prevention included free ventilation of houses and wholesome and abundant food. Milk should be boiled, and meat should be carefully inspected, or else the cattle tested for infection. Cures for the disease included abundant food, particularly of a fatty nature, and life in the open air. 1901 congress (London) The British Congress on Tuberculosis was held in London on 22–27 July 1901. About 2,500 British and foreign delegates were invited, including many eminent pathologists and physicians. The Duke of Cambridge opened the congress on behalf of the king. Great stress was placed on the importance of early treatment, but it was also noted that the patient's dependents must often receive aid. Better sanitary arrangements were also seen as important, and improved housing