Many researchers scattered in different countries collect thousands of observations, discover new signs of diseases and study the effects of new and old remedies. This movement of medical thought was facilitated by the arrangement of clinics. Straten in Utrecht and Otton Gurn in Leiden introduced clinical teaching, which was especially developed in the hands of Selvius le Boe. 40 years later, Burghav gave his lectures a practical character, perfectly arranged the hospital. Following the example of Burgava and other professors began to establish clinics in Rome and other Italian. cities, Vienna, Würzburg, Copenhagen, etc. Of the practical doctors who were hostile to all kinds of theories, Sydenham should be mentioned first of all. His ability to observe accurately is found in the description of epidemics during which he tried to discover a certain legitimacy and consistency. Stoll was in the same direction, giving accurate descriptions of chronic diseases and epidemics. Of the other epidemiologists who have presented more or less remarkable works, let us name: Dimerbrök, Rivin, Morley, Shakht, Shrök, Kanodda, Lange, Valkarengi, and others. Many people were engaged in the study of diseases inherent in known areas. Bontius described the diseases of India, Kaempfer - Persia, Japan and Siam, Piso - Brazil, etc. Separate descriptions of the distribution of diseases inspired the idea to present an image of morbidity depending on the climate. The first attempt of this kind was made by Falconer; later similar works were presented by Finke, Wilson, and Karteiser. Collections of observations, which were published in separate editions or published in journals, are very instructive.