834 KARL ERNST VON BAER. 



patliies of the minister of public instruction and of the professors of 

 the university. But the very modest allowance he received from the 

 university, spite of occasional aid from outside, forced upon him a dis- 

 couraging economy in the administration of the museum. 



In the midst of all these professional duties, he found time for his spe- 

 cial studies in geology, anthropology, and anatomy, and continued his 

 systematic observations in embryology. As early as 1818, he had laid 

 the foundation of his great generalization on the distinct modes of de- 

 velopment for the four great branches of the animal kingdom, and in 

 182G he published, in Burdach's ''Physiology," his embryology of the 

 chick and frog. Chiefly attracted by the development of Vertebrates, 

 he first showed the identity of the mammalian egg, including that of man, 

 with the (^gg of fishes. These results first appeared in the memorable 

 treatise entitled " De Ovi Mammalium et Hominis Genesi," in 1827. 

 It was in advance of the time, and, with the exception of a sneering 

 comment on the egg found by a great man in the ovary of a woman, 

 was hardly mentioned in the annual scientific reports of the day. 

 The light thrown upon this paper by the writnigs of a later set of 

 embryologists, Rathke, Bischoff", and Kolliker, first made known the 

 vast importance of the theory of embryonic layers announced by Von 

 Baer. It was followed in 1828 by the first volume of his " Entwicke- 

 lungsgeschichte ; " but it was only in 1831 that Von Baer was 

 rewarded by the French Academy with one of its prizes. The Eng- 

 lish were even slower to recognize his merit, and the first English 

 translation of the most important biological work of the century, the 

 " Entwickelungsgeschichte " appeared only in 1855. 



In 1829, Von Baer was invited to take charge of the zoological 

 department in the Academy of St. Petersburg. He had, however, a 

 certain distrust of the position from the long-continued delay in the 

 publication of the great work of Pallas. On this account, although 

 they were inclined to grant all he asked, he decided to remain at 

 Konigsberg, making it a condition, however, that he should have cer- 

 tain facilities for his embryological investigations. He now devoted 

 himself especially to his investigations on the special modes of devel- 

 opment characterizing the principal types of the animal kingdom, the 

 results of which were embodied in the second volume of his " Ent- 

 wickelungsgeschichte." During the second period of his Konigsberg 

 life, the social and ^wlitical circumstances became less favorable to his 

 aims, and in 1832 he renewed his negotiations with St. Petersburg; 

 this time with a different result, for in 1834 we find him established 

 there. He now entered on a life of greater activity and variety than 



