Abstract
Seven unknown letters from 1823 to 1831 are published. The famous discoverer of the mammal's egg and founder of the modern embryology Karl Ernst von Baer (1792â1876), born as a German in Estonia and then anatomist and zoologist at Königsberg University, wrote them to his publisher Ludwig F. Froriep in Weimar and his son and successor. Robert F. Baer offered his co-work with a dictionary of natural history (which he criticized), he proposed a map of all research voyages everywhere in the world, and he sent a few small papers about local birds. To Robert F. Baer gave some recommendations concerning his career; he asked for details of a death elephant, and he told that they were awaiting the cholera