and teaching responsibilities did not hinder Baer from his 

 unparalleled capability to study the development of different 

 vertebrates, and also to perform a number of special 

 investigations in zoology, comparative anatomy, and anthropology 

 (84) . In 1826 Baer, during the course of his embryological 

 investigations, made a wonderful discovery by observing the 

 ovum in the ovary of mammals. This discovery he reported the 

 following year in an extensive letter to the Petersburg Academy 

 of Science, 10 which in answer selected Baer as corresponding 

 member. 



In 1827 the Petersburg academician, botanist (Karl Bernhard) 

 Trinius, suggested to Baer that he occupies Pander's position as 

 an academician, since Pander had left his post. In 1828 Baer's 

 election as a member of the Petersburg Academy of Science occurred, 

 and by the end of the next year he arrived in Petersburg. 

 Apparently, once there Baer could not satisfy what he considered 

 the necessary conditions for work, and he returned to Konigsberg, 

 apologizing for his refusal of the academic post. In the 

 following three to four years, Baer continued with his highly 

 intensive study of embryology, and as a result the first 

 volume of his classical work, UBER ENTWICKLUNGSGESCHICHTE 

 DER TH I ERE, came to light in 1828. In order to accomplish this 

 work Baer had to overcome considerable organizational and 

 material difficulties created by the unfriendly attitudes of the 

 Ministry of Education towards him. This strengthened his desire 

 to return to Russia. Travel to the mother country and his 

 family estate in Estonia corresponded with the second selection 

 of Baer to the Petersburg Academy of Science, and from 1834 he 

 remained permanently in Russia. 



In Petersburg Baer was involved in various studies, which to 

 a considerable extent drew him away from his embryological 

 investigations. At this time he accomplished and published 

 only some special work in embryology; his attention was 

 particularly drawn to mutations, which he considered as interest- 

 ing with the normal course of development. The study of 

 mutations he considered important for promoting understanding 



10. Baer, DE OVI MAMMALIUM ET HOMINIS GENESI 

 EPISTOLA AD ACAD. IMP. SCIENTIARIUM 

 PETROPOLITANAM. Leipzig, 1827. 



280 



