In 1777, Pallas was appointed a member of topographic division Russian Empire in 1782 - Advisor to the board in 1786 - Historiography, the Admiralty Board. He continues to pursue research in various fields.

   In 1781 he published the work "Remarks on cestoid in humans and animals", to which Pallas, described in detail 21 species of parasitic cestode, suggested measures to combat worms.

   In 1780-ies, he worked intensively on the preparation of a common set of plant Russia - "The flora of Russia". Due to lack of funds managed to publish only two issues of this extensive work (1784 and 1788), describing some 300 species of plants and stunning illustrations.

   In 1784 Catherine II became interested in the idea of Cours de Zhebelena of the unity of all world languages, engaged in comparative linguistics, and then provided the material of his study of Hartwicht-Ludwig-Christian Bacmeister. In April 1785 Catherine II brought to the work of Pallas, which were compiled by the program and application form to collect the material and the comparative analysis of the languages of the peoples of Russia and all over the world. The questionnaire was sent not only to administrators of Russian provinces, but also in Europe, China, Brazil and North America, where President George Washington authorized the governors of the United States to gather material for scholars Occupation Russian Empress. It was anticipated that the study could "lead to the solution of the existence of a primitive language". In doing so, particular attention should be given to the speaker of "inner Asia" - the area of the Pallas considered a hotbed of origin of the human race.

   Finished the study, Pallas issued on behalf of Catherine II comparative dictionary in two parts (1787-1789), which were submitted more than 200 languages and dialects of peoples of Asia and Europe, including 142 Asian languages, 51 European languages and 50 languages of the peoples of the North. The first volume includes 273 concepts - kinship terms, names of animals, pets, birds, natural phenomena, etc., in a special "vocabulary" was presented to 149 languages. The second volume contains the names of simple numerals to 222 languages. In 1790-1791 years the dictionary was reprinted in the amended and corrected. The new edition of the four were presented to 272 languages and dialects, among which also includes 30 languages and 23 African American language. According to the proposal of Catherine II, the structure of the dictionary was changed. As can be seen from a new name - "A comparative dictionary of all languages and dialects, for order", the words of various languages of the world placed in it in alphabetical order. In compiling the dictionary Pallas also used materials Bakmeystera.

   Despite the unprecedented idea, linguistic project of Catherine II and Pallas had a number of flaws and was rated by some contemporaries (for example, Professor Kraus of Konigsberg), as a quick and ill-essay. Questioned was the accuracy of reproduction of words, taken from people without written language, the drafters did not foresee any geographical position, language or origin. All foreign-language words were written by Russian letters, it is about reflecting the real pronunciation. Data collection was conducted in haste and often a layperson, resulting in a dictionary, it was allowed a lot of errors and distortions in the transmission of sound words. However, the criticism has contributed to the development of the method has not yet been born science of philology.

   As a manifestation of the special esteem in which Catherine II during this period has been a scientist, can be interpreted by the fact that she had instructed Pallas science teaching her grandson Constantine and Alexander.

   For no obvious reasons Pallas was dismissed from the cases in 1792. In 1793-1794 years he has committed funds for personal travel to the southern provinces of Russia - from St. Petersburg to Volga river, Astrakhan, the Caspian lowland, in the North Caucasus, the Crimea and Ukraine. Here he studied climatology in southern Russia and Ukraine, shortly before the annexation by Russia. In the expedition was a young artist from Leipzig Christian Geissler. In 1796 Pallas was sent to Simferopol, where the Empress granted him an estate Shulyu - vast estates and home. On the way to the Crimea, he visited Tula, Kursk, and Ekaterinoslav (Dnipropetrovsk). Settled in the Crimea, Pallas examined nearly the entire southern coast of the peninsula.

   In recent years, among other things, Pallas was preparing the three basic labor fauna Russia "Russian-Asian Zoology", which were submitted more than 900 species of vertebrates, including 151 species of mammals, of which about 50 new species. According to the vastness and thoroughness of the material, describe the diversity of animals it was not long equal. Until the beginning of XX century, the book has remained the main source of knowledge about the fauna of Russia. The first volume was ready already in 1806, but printing and production of light was delayed by a quarter-century because of the artist Geyslera, who went to Germany. An effort to expedite the preparation of drawings, Pallas in 1810 returned to Berlin, but he did not see his main work published. Two weeks before the 70 th anniversary, Sept. 8, 1811, the scientist died.

   An effort to expedite the preparation of drawings, Pallas in 1810, selling the name back to Berlin, but he did not see his main work published. Two weeks before the 70 th anniversary, Sept. 8, 1811, the scientist died.