Warnek's work produced a new page in embryology, 

 directing the investigations of the history of individual 

 development towards the study of subsequent changes of the 

 fertilized ovum and the forming from it of blastomeres, and 

 towards a study of the fate of the separate blastomeres and 

 their descendants during the subsequent formation of the 

 embryo. In this sense Warnek's investigation foreshadowed 

 the works of A. 0. Kovalevsky and his countless followers 

 who were studying either descriptively or experimentally the 

 transformation of the elementary organs of the dividing ovum 

 the blastomeres into systems of organs of the forming organism 



N. A. Warnek was for a long time undeservedly forgotten. 

 His classical work is rarely cited and not always mentioned 

 even in the embryological summaries and textbooks, although 

 he unquestionably deserved a place of honor in the history 

 of Russian and world embryology. 



The investigations of Grube, Nordmann and Warnek were 

 monographical descriptions of the embryological development 

 of certain representatives of the invertebrates. These works, 

 with all their significance, did not answer, however, the 

 requirements of comparison of the phenomena of development 

 in different types of animals. The first attempt to include a 

 wide number of invertebrates in embryological investigations 

 was done by A. Krohn, whose services in this sphere are much 

 undervalued. Krohn was so thoroughly forgotten that his 

 name was not mentioned either in the encyclopaedias or in 

 the biographical reference books. 30 The following circumstance 

 is sufficient to attract the attention of historians of Russian 

 science to Krohn. 



During the first committee discussion of Baer's prize of 

 the Russian Academy of Science in 1867, considering possible 



30. For help given in researching biographical and biblio- 

 graphical data about Krohn, the author thanks the 

 biological section of Saltykov-Sedrin Gos. Publichnaya 

 library in Leningrad, especially librarian V. L. Levin 



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